5. Appraisal of Adverse Effects on Integrity

5.1. Introduction

57. This section provides some background information and explanation for the approach taken to assessing the potential impacts of the Proposed Development on European sites designated for ornithological features and presents the Stage Two assessments for the site features for which LSE has been identified ( Table 3.1   Open ▸ ), with the Stage Two assessments  for the sites identified in Table 3.1   Open ▸ are presented in sections 5.7 to 5.9 (including consideration of both the project alone and in-combination effects).
58. The assessments for each European site in this section are structured such that they are presented in their entirety for each of the relevant qualifying features in turn (including consideration of all relevant effect pathways and of both the project alone and in-combination scenarios). A cross-referencing approach has been adopted to aide readability and reduce repetition where relevant, but that this has been carefully carried out to ensure that all information required for a robust HRA of each site is presented. 
59. Furthermore, for the ornithological features of breeding seabird colony SPAs, a dual assessment approach has been adopted (see section 5.4), with the outputs from both approaches presented within the assessment section for each relevant qualifying feature. This enables the outputs and conclusions of the different assessment approaches for each qualifying feature to be more readily examined and compared.
60. A summary of all Appropriate Assessments undertaken within this report is provided in the concluding section of this report (see section 6).
61. Integrity matrices are not provided for this Part of the RIAA given that these are a requirement of the Planning Inspectorate of England and Wales (PINS 2022), rather than Scottish Ministers. Integrity matrices have not been requested in the Scoping Opinion or during the Roadmap Process (Offshore EIA Report, volume 3, appendix 11.8. annex A).

5.2. Relevant Effect Pathways

5.2.1.    Construction and Decommissioning

Direct habitat loss

62. The potential for LSE as a result of this effect pathway during construction and decommissioning is identified in relation to the Outer Firth of Forth and St Andrews Bay Complex SPA only. This potential arises because the Proposed Development export cable corridor will pass through this SPA (HRA Stage One Screening Report; SSER, 2021b). Direct habitat loss associated with the Proposed Development export cable corridor during either construction or decommissioning will be temporary and of trivial extent relative to the foraging ranges used by qualifying features from the breeding seabird colony SPAs (e.g. Woodward et al., 2019) (as opposed to the Outer Firth of Forth and St Andrews Bay Complex SPA) whilst qualifying features of the migratory waterbird SPAs are not expected to forage or roost within or in the vicinity of the Proposed Development.  
63. Effects during decommissioning of the Proposed Development export cable corridor are assumed to be as for construction (see Table 4.1   Open ▸ ), whilst indirect loss of habitats used by ornithological features is assessed as displacement.
64. There is considered to be potential for LSE from direct habitat loss during construction and decommissioning for all of the qualifying features of the Outer Firth of Forth and St Andrews Bay Complex SPA (Table 3.1).

Disturbance

65. For the purposes of determining LSE, disturbance and displacement were considered together but they are treated as separate effect pathways in the current assessment, as advised in the Scoping Opinion (Offshore EIA Report, volume 3, appendix 6.2). As detailed in the HRA Stage One Screening Report (SSER, 2021b), disturbance during construction and decommissioning is relevant to all of the qualifying features of the Outer Firth of Forth and St Andrews Bay Complex SPA, certain of the qualifying features of the breeding seabird colony SPAs (dependent on species’ sensitivities to disturbance and as detailed in the HRA Stage One Screening Report) and the non-breeding red-throated diver feature of the Firth of Forth SPA (and Ramsar site). For the latter, the potential for LSE is identified due to the high sensitivity of this species to disturbance (Furness et al. 2013; Jarrett et al. 2018; Fliessbach et al. 2019; Goodship and Furness 2022). Disturbance during construction and decommissioning is screened out for other qualifying features of the migratory waterbird SPAs because they are not expected to forage or roost within or in the vicinity of the Proposed Development and there is no potential for effects on such species when passing through (or over) the Proposed Development on migration.
66. During construction, increased levels of vessel traffic and other activities associated with the installation of the wind turbine foundations and other infrastructure may cause disturbance to seabirds which use the Proposed Development array area and surrounding waters for purposes such as foraging and roosting. Potential effects from these sources of disturbance are relevant to qualifying features of the breeding seabird colony SPAs as well as to the seabird qualifying features of the Outer Firth of Forth and St Andrews Bay Complex SPA which may use those parts of the SPA that are in closest proximity to the Proposed Development array area. Vessel activity associated with cable laying along the route of the Proposed Development export cable corridor, which transits the Outer Firth of Forth and St Andrews Bay Complex SPA, also has the potential to result in disturbance to the qualifying features of this SPA, as well as to qualifying features of the breeding seabird colony SPAs and to the non-breeding red-throated diver feature of the Firth of Forth SPA (and Ramsar site). Similar activities during the decommissioning phase mean that there is the potential for such disturbance effects to occur on the same range of SPAs (and Ramsar site) and qualifying features during this later phase.
67. Such temporary disturbance may cause changes in behaviour and could potentially lead to a reduction in foraging opportunities or increased energy expenditure, resulting in decreased survival rates or productivity in affected populations.
68. The European sites and qualifying features for which disturbance during construction and decommissioning is considered to have the potential to result in an adverse effect are detailed in Table 3.1   Open ▸ .

Displacement

69. As stated above, disturbance and displacement were considered together in the HRA Stage One Screening Report (SSER, 2021b), but are treated as separate effect pathways in the current assessment, as advised in the Scoping Opinion (Offshore EIA Report, volume 3, appendix 6.2). Displacement during the construction and decommissioning phases could arise as a consequence of disturbance, with the potential for effects to occur on the same range of SPAs (and Ramsar site) and qualifying features as identified in relation to disturbance during construction and decommissioning (see above and as detailed in the HRA Stage One Screening Report.
70. Displacement may cause birds to be excluded from areas of preferred habitat and (where this affects foraging habitat) could potentially lead to a reduction in foraging opportunities, increased competition or increased energy expenditure, resulting in decreased survival rates or productivity in affected populations. As with disturbance, it is assumed that the potential for displacement during decommissioning is similar to that for the construction phase, with the potential for effects expected to extend over a period of similar, or shorter, duration.
71. The European sites and qualifying features for which displacement during construction and decommissioning is considered to have the potential to result in an adverse effect are detailed in Table 3.1   Open ▸ .

Changes to prey availability

72. This effect pathway is relevant to the qualifying features of the Outer Firth of Forth and St Andrews Bay Complex SPA and the breeding seabird colony SPAs, but not of the migratory waterbird SPAs (and Ramsar sites). Indirect effects on seabirds may occur as a result of changes in prey distribution, availability or abundance. Reduction or disruption to prey availability for seabirds may cause displacement from foraging grounds in the area or reduced energy intake, affecting survival rates or productivity in the population in the short-term. Waterbird qualifying features of the Outer Firth of Forth and St Andrews Bay Complex SPA could be similarly affected, given the Proposed Development export cable corridor passes through the SPA.
73. During construction there are several ways in which effects on prey availability may manifest, notably via underwater noise from piling affecting fish abundance and distribution, increases in suspended sediment concentrations (SSC) reducing the abundance and distribution of fish or the efficacy of foraging by seabirds and disturbance to prey species affecting their abundance and availability. Similar effects could occur during decommissioning but with the additional possibility that prey abundance could decline from the levels present during the operation and maintenance period. This could occur if the sub-surface structures associated with the Project lead to increases in fish abundance within the Proposed Development array area and export cable corridor via the provision of artificial reef habitats (Smyth et al., 2015 and references therein).
74. The European sites and qualifying features for which changes to prey availability during construction and decommissioning is considered to have the potential to result in an adverse effect are detailed in Table 3.1   Open ▸ .

5.2.2.    Operation and Maintenance

Direct habitat loss

75. The potential for LSE as a result of this effect pathway during operation and maintenance is identified in relation to the Outer Firth of Forth and St Andrews Bay Complex SPA only. This potential arises because the Proposed Development export cable corridor will pass through this SPA (HRA Stage One Screening Report; SSER, 2021b). Direct habitat loss associated with the Proposed Development during operation and maintenance will be of trivial extent relative to the foraging ranges used by qualifying features from the breeding seabird colony SPAs and the extent of marine habitats available for other functions e.g. roosting (e.g. Woodward et al. 2019). The qualifying features of the migratory waterbird SPAs are not expected to forage or roost within and around the vicinity of the Proposed Development, so that there is no LSE from this pathway in relation to the migratory waterbird SPAs (HRA Stage One Screening Report; SSER, 2021b).
76. The indirect loss of habitats used by ornithological features is assessed as displacement.
77. There is considered to be potential for LSE from direct habitat loss during operation and maintenance for all of the qualifying features of the Outer Firth of Forth and St Andrews Bay Complex SPA (Table 3.1).

Disturbance

78. As for construction and decommissioning, disturbance and displacement during the operation and maintenance phase were considered together for the purposes of determining LSE but are treated as separate effect pathways in the current assessment (Offshore EIA Report, volume 3, appendix 11.8; SSER, 2021b). During operation and maintenance, levels of vessel traffic associated with the Proposed Development array area will be substantially lower than during construction and decommissioning, whilst there will also be an absence of activities analogous to those associated with the installation of infrastructure during construction (Table 4.1). The presence of the operational wind turbines in the Proposed Development array area has the potential to result in disturbance to seabirds foraging, roosting or commuting within the vicinity of this area. The offshore export cables are immobile structures on the seabed with minimal maintenance requirements, so that there will be little associated vessel activity during operation and maintenance (Table 4.1). As such, there is considered to be no potential for LSE due to disturbance associated with the Proposed Development export cable corridor during operation and maintenance.
79. As detailed in the HRA Stage One Screening Report (SSER, 2021b), disturbance during operation and maintenance is relevant to certain of the qualifying features of the Outer Firth of Forth and St Andrews Bay Complex SPA and of the qualifying features of the breeding seabird colony SPAs. This is dependent on species’ sensitivities to disturbance, whilst for the Outer Firth of Forth and St Andrews Bay Complex SPA LSE is also excluded for those features which are unlikely to occur within the vicinity of the Proposed Development array area (i.e. the waterbirds and those seabird species with relatively restricted breeding season foraging ranges or which predominantly use inshore habitats). No LSE from disturbance during operation and maintenance is identified in relation to the qualifying features of the migratory waterbird SPAs because they are not expected to forage or roost within and in the vicinity of the Proposed Development and there is no potential for effects on such species when passing through (or over) the Proposed Development on migration (noting that the absence of effects associated with the Proposed Development export cable corridor means that there is no LSE in relation to the non-breeding red-throated diver feature of the Firth of Forth SPA and Ramsar site.
80. Disturbance effects during operation and maintenance may cause changes in behaviour and could potentially lead to a reduction in foraging opportunities or increased energy expenditure, resulting in decreased survival rates or productivity in affected populations.
81. The European sites and qualifying features for which disturbance during operation and maintenance is considered to have the potential to result in an adverse effect are detailed in Table 3.1   Open ▸ .

Displacement

82. As stated above, disturbance and displacement were considered together in the HRA Stage One Screening Report (SSER, 2021b) but are treated as separate effect pathways in the current assessment, as advised in the Scoping Opinion (Offshore EIA Report, volume 3, appendix 6.2). Displacement during the operation and maintenance phase could arise as a consequence of disturbance, with the potential for effects to occur on the same range of SPAs (and Ramsar sites) and qualifying features as identified in relation to disturbance during operation and maintenance (see above and as detailed in the HRA Stage One Screening Report).
83. Displacement effects during operation and maintenance may cause birds to be excluded from areas of preferred habitat and (where this affects foraging habitat) could potentially lead to a reduction in foraging opportunities, increased competition or increased energy expenditure, resulting in decreased survival rates or productivity in affected populations.
84. The European sites and qualifying features for which displacement during operation and maintenance is considered to have the potential to result in an adverse effect are detailed in Table 3.1   Open ▸ .

Barrier effects

85. As detailed in the HRA Stage One Screening Report (SSER, 2021b) and in Table 3.1, the potential for LSE as a result of this effect pathway is identified in relation to the migratory waterbird qualifying features of the Outer Firth of Forth and St Andrews Bay Complex SPA, certain of the features from the breeding seabird colony SPAs (dependent on species’ known susceptibility to barrier effects and as detailed in the HRA Stage One Screening Report) and the qualifying features of the migratory waterbird SPAs and Ramsar sites. Although the Scoping Opinion advised that a LSE as a result of barrier effects should also be considered for the breeding gannet qualifying feature of the Outer Firth of Forth and St Andrews Bay Complex SPA, further consultation determined that the original conclusions of the HRA Stage One Screening Report were valid and that LSE could be excluded for this feature (see Table 3.1 and volume 3, appendix 6.2 of the Offshore EIA Report).
86. Barrier effects may arise if offshore wind farms act as a barrier to the movement of birds due to the presence of the wind turbines, so that flight routes would deviate around or over the Proposed Development array area. This could impose additional flight time and energetic costs resulting in decreases in annual rates of survival and / or breeding productivity amongst affected populations (Masden et al., 2010, Searle et al., 2018). For the purposes of the current assessment, predicted impacts from barrier effects are incorporated with those of displacement, based on the application of the SNCB matrix approach (SNCBs 2022; Offshore EIA Report, volume 3, appendix 11.4). This follows the standard approaches used in the prediction of these effects in assessments for UK offshore wind farms, with outputs from SeabORD (Searle et al., 2018) provided in the Offshore EIA Report, volume 3, appendix 11.4, annex D for context (noting the conclusions of the SeabORD sensitivity analysis presented in the Offshore EIA Report, volume 3, appendix 11.4, annex H).
87. The European sites and qualifying features for which barrier effects during operation and maintenance is considered to have the potential to result in an adverse effect are detailed in Table 3.1   Open ▸ .

Collision risk

88. As detailed in the HRA Stage One Screening Report (SSER, 2021b) and in Table 3.1, the potential for LSE as a result of this effect pathway is identified in relation to the migratory waterbird qualifying features of the Outer Firth of Forth and St Andrews Bay Complex SPA, certain of the qualifying features of the breeding seabird colony SPAs and the qualifying features of the migratory waterbird SPAs (and Ramsar sites). The qualifying features of the breeding seabird colony SPAs for which LSE are concluded are those deemed to have potential sensitivity to collision risk which is, in part, based upon their typical flight heights (Garthe and Hüppop 2004, Furness et al., 2013, Johnston et al., 2014a, b).
89. Collision risk is associated with the Proposed Development array area and, specifically, with the potential for seabirds and/or migratory waterbirds to collide with the rotating blades of the wind turbines as they fly through this area (Skov et al., 2018). Collisions may result in direct mortality, which may be additive to existing (i.e. baseline) mortality within the population and could cause population declines or, in some situations, prevent population recovery. Therefore, seabird species which forage within, or commute through, the Proposed Development array area may be vulnerable to such effects, as is also the case for migratory waterbirds which transit this area during the passage periods. Given the offshore location of the Proposed Development array area, it is extremely unlikely that any of the migratory waterbird species associated with the SPAs (and Ramsar sites) screened in for LSE would make more frequent movements across the Proposed Development array area (e.g. when commuting between foraging and roosting sites) and, for these species, it is considered that the potential for collisions is limited to their migration periods.
90. The European sites and qualifying features for which collision during operation and maintenance is considered to have the potential to result in an adverse effect are detailed in Table 3.1   Open ▸ .

Changes to prey availability

91. As for the construction and decommissioning phases, this effect pathway is relevant to the qualifying features of the Outer Firth of Forth and St Andrews Bay Complex SPA and the breeding seabird colony SPAs, but not of the migratory waterbird SPAs (and Ramsar sites), during operation and maintenance. Reduction or disruption to prey availability through temporary and long-term subtidal habitat loss/disturbance, increased SSC and deposition, electromagnetic fields (EMF) from subsea electrical cabling, and colonisation of subsea structures could affect ornithological features foraging within and in the vicinity of the Proposed Development array area and export cable corridor.
92. The European sites and qualifying features for which changes to prey availability during operation and maintenance is considered to have the potential to result in an adverse effect are detailed in Table 3.1   Open ▸

5.3. Plans and Projects for the In-Combination Assessments

93. The plans and projects set out in Table 5.1   Open ▸ have been considered within the in-combination assessment for European sites designated for ornithological features.
94. The plans and projects included in this in-combination assessment have been derived in part, from the CEA longlist presented in volume 3, appendix 6.4 of the Offshore EIA Report. Further detail on the plans and projects comprising the in-combination assessment is provided in volume 3, appendix 11.6, annex E of the Offshore EIA Report.

Table 5.1:  List of Other Developments with Potential for In-Combination Effects on Ornithological Features

5.4. The Dual Approach to Assessment

95. The Applicant has for the most part adopted the advice on ornithological assessment parameters advised in the Scoping Opinion (volume 3, appendix 6.2 of the Offshore EIA Report). Nevertheless, the Applicant considers elements of the Scoping Opinion to be over-precautionary and a departure from standard advice/practice. As such, the Applicant has presented a dual assessment of potential displacement/barrier effects and collision effect pathways during operation based on:

• The ‘Scoping Approach’; and
• The ‘Developer Approach’.
  96. With respect to assessing potential displacement/barrier effects, Scoping Opinion contained advice on the displacement rates and displacement mortality rates to be applied to the SNCB matrix approach (SNCBs 2022; volume 3, appendix 11.4 of the Offshore EIA Report). These rates have been used for the purposes of assessment under the Scoping Approach.
  97. Under the Developer Approach, these rates differed in some cases, based upon available evidence for displacement, the extent of a features ranging behaviour (particularly in the non-breeding periods), previous precedent and a need to incorporate precaution within the assessment (Table 5.2; volume 3, appendix 11.4 of the Offshore EIA Report).
  98. Evidence and justification for the rates used under the Developer Approach is presented in volume 3, appendix 11.4, annex G of the Offshore EIA Report, with a summary of the rates taken forward for assessment purposes presented in Table 5.2   Open ▸ .

Table 5.2: Displacement and Mortality Rates Used for the Scoping and Developer Approaches.

99. With respect to estimating collision risk, the Developer Approach is largely in accordance with the Scoping Opinion, as the two approaches differ only in their use of input monthly density estimates of flying birds of the assessed species within the Proposed Development. Justification for this difference is presented in volume 3, appendix 11.3 of the Offshore EIA Report.

5.5. Highly Pathogenic Avian Influenza (HPAI)

100. In October 2021, a new strain of Highly Pathogenic Avian Influenza (HPAI) was identified in the UK (H5N1). Since then, 120 further locations of infection in captive birds and poultry have been identified across the UK, and 354 separate locations of infection across wild birds of 63 species have been identified across 76 countries worldwide (DEFRA, 2022). The greatest proportion of infection to date has been observed in swans, geese and ducks, and these species may form a natural reservoir of the virus (DEFRA, 2022).
101. There have also been HPAI (H5N1) infections recorded in several seabird species, including gannet at Bass Rock and Hermaness, Shetland (Martin, 2022) and Isle of Noss (Philip and Tyler, 2022), guillemot at St Abb’s Head (Hall, 2022), great skua at St Kilda, Fair Isle, Isle of Noss and Foula (Banyard et al., 2022; NatureScot, 2022a; Philip and Tyler, 2022) and kittiwake, great black-backed gull and terns at the Isle of May (Steel pers comm. 19 July 2022; NatureScot, 2022a). As of August 2022, there had been no mass mortalities observed in Scottish tern, razorbill or puffin colonies (Philip and Tyler, 2022). However, the full magnitude of impact is currently highly uncertain and a task force has been established to coordinate a national response to tackling the outbreak.
102. In response to the outbreak in the Forth and Tay region, the Applicant, in collaboration with other Forth and Tay developers, is currently co-funding a monitoring study of the Bass Rock gannet colony to examine the impacts of HPAI on gannet survival and to explore levels of immunity within the population which will be key to understanding the long-term implications of the outbreak.
103. Given the current uncertainty regarding the short, medium and long-term effects of the 2022 HPAI outbreak on seabird colony abundance and vital rates (productivity and survival), this Part of the RIAA has been compiled following the most recent advice received from MS-LOT and NatureScot, where the Applicant was advised to progress with assessment based on the advice received both prior to, and following the HPAI outbreak as outlined in the Offshore EIA Report Table 2.1, volume 3, appendix 5.1, the EIA Audit document (teleconference between the Applicant, NatureScot and MS-LOT on 28/07/2022). As such, no amendments or assumptions have been made to the assessment in light of the HPAI outbreak.

5.6. Appropriate Assessments: Marine SPA

5.6.1.    Outer Firth of Forth and St Andrews Bay Complex SPA

European Site Information and Conservation Objectives

104. The Outer Firth of Forth and St Andrews Bay Complex SPA provides supporting habitat for a range of breeding and non-breeding seabird and waterbird species.
105. The Outer Firth of Forth and St Andrews Bay Complex SPA stretches from Arbroath to St. Abb’s Head encompassing the Firth of Forth, the outer Firth of Tay and St. Andrews Bay and comprises an area of 2,720.68 km2. The site extends beyond the 12 nautical miles (nm) boundary of territorial and offshore waters to encompass key seabird feeding areas.
106. The Outer Firth of Forth and St Andrews Bay Complex SPA attracts one of the largest and most diverse concentrations of marine birds in Scotland. During the non-breeding season, it provides important wintering grounds used for feeding, moulting and roosting by a variety of waterfowl including the largest aggregations of red-throated diver and common eider in Scotland. The Firth of Forth is also notable for its concentrations of wintering gulls, including little gull, kittiwake, black-headed gull, common gull and herring gull. Together with guillemot, shag and razorbill these species contribute to an assemblage of over 40,000 seabirds using the site during the non-breeding season.
107. The site also encompasses feeding grounds for breeding common tern, Arctic tern and shag nesting colonies. During the breeding season, kittiwake, gannet, herring gull, guillemot, puffin, and Manx shearwater also contribute to the SPA assemblage of over 100,000 seabirds.
108. The nearshore boundary of the Outer Firth of Forth and St Andrews Bay Complex SPA follows the Mean Low Water Springs (MLWS) mark. 
109. The Proposed Development offshore export cable corridor runs through this SPA, whilst the Proposed Development array area is 2 km from the SPA boundary at its closest point (Figure 3.1).
110. There are 21 Annex I qualifying features and the site qualifies under Article 4.2 by regularly supporting breeding seabirds, non-breeding seabirds and waterfowl assemblages ( Table 5.3   Open ▸ ). The potential for LSE has been identified in relation to all 21 species ( Table 5.3   Open ▸ ), with the effect pathways associated with LSE for each of these detailed in Table 3.1   Open ▸ and set out in the assessment below.
111. The conservation objectives of this SPA (as determined from NatureScot’s SiteLink (NatureScot 2022) are:

1. To ensure that the qualifying features of the Outer Firth of Forth and St Andrews Bay Complex SPA are in favourable condition and make an appropriate contribution to achieving Favourable Conservation Status.

2. To ensure that the integrity of the Outer Firth of Forth and St Andrews Bay Complex SPA is restored in the context of environmental changes by meeting objectives 2a, 2b and 2c for each qualifying feature:

2a The populations of the qualifying features are viable components of the Outer Firth of Forth and St Andrews Bay Complex SPA.

2b. The distribution of the qualifying features is maintained throughout the site by avoiding significant disturbance of the species.

2c. The supporting habitats and processes relevant to qualifying features and their prey resources are maintained, or where appropriate restored, at the Outer Firth of Forth and St Andrews Bay Complex SPA.

112. On the basis that shag, kittiwake, common tern and herring gull are considered to be in unfavourable condition the overarching objective for this site is a restore objective (NatureScot and JNCC 2021)
113. Further information on this European site is presented in Appendix 3A.
114. The citation population size and site condition status for each qualifying feature are detailed in Table 5.3   Open ▸ , along with whether the potential for LSE has been determined for the qualifying feature (as detailed in Table 3.1   Open ▸ ).

Table 5.3: Details on the qualifying features of the Outer Firth of Forth and St Andrews Complex SPA

Assessment for the Eider Population

115. Eider occur in coastal waters throughout northern Britain, particularly in shallow water of usually less than 3 m where suitable prey of molluscs and crustaceans. Breeding colonies are often large and flocks of many thousands of birds can occur in suitable nearshore areas. It is the commonest breeding seaduck in the UK with a breeding population of around 31,000 pairs of which approximately 20,000 pairs occur in Scotland (Forrester et al. 2007).
116. Following breeding, eiders may congregate into large moulting flocks in specific areas with main areas in eastern Scotland being Firth of Forth, Shetland, Ythan, Aberdeen Bay and Montrose Basin (Cork Ecology 2004).
117. Although eiders in the UK are largely non-migratory there is some winter dispersal away from the breeding areas with a proportion of birds from North-east Scotland wintering in the Tay Estuary. The east coast of Scotland holds a substantial proportion of the UK wintering population with approximately 59,000 birds. The major wintering areas along the east coast of Scotland are the Tay Estuary, Firth of Forth, Montrose Basin, Orkney, Ythan and the Moray Firth (Forrester et al. 2007).
118. The site reference population of 22,000 individuals has been calculated on multi-year programme of aerial, boat-based and land-based surveys (Lawson et al. 2015). Based on Wetland Bird Survey (WeBS) data the peak mean population size has fluctuated annually but has remained relatively stable (Figure 5.1).

Figure 51: Eider population trend at the Outer Firth of Forth and St Andrews Bay Complex SPA for the period 2001 - 2020. The orange line shows the site reference population size for the SPA (2001/02 – 2004/05 peak mean 22,000 individuals). Data are from the Wetland Bird Survey Database (BTO 2022)

119. Site specific advice relating to eider is to:

• Maintain the population of non-breeding eiders at a stable or increasing trend relative to the site reference population.
• Ensure eider can move safely between the site and important areas of functionally linked land outwith the site.

The Potential for Impacts on the Eider Population

120. Potential impacts on the Outer Firth of Forth and St Andrews Bay Complex SPA eider population screened in for assessment are outlined in section 3.1 and in the HRA Stage One Screening Report (SSE Renewables, 2021). The assessment of potential barrier and collision impacts on eider with the Firth of Forth SPA are addressed in the Migratory Bird Assessment (Section 5.8)
121. Potential impacts from the Proposed Development could arise during construction, operation and maintenance and decommissioning and could cause direct habitat loss, changes in prey availability and disturbance and displacement. Consequently, the focus of the assessment for this SPA population is concerned with all the conservation objectives
122. No eider were recorded during any of the site specific surveys undertaken across the Offshore Ornithology Study Area. Intertidal and nearshore monthly surveys undertaken at the Skateraw landfall between July 2020 and June 2021 recorded eider in each month with a maximum count of 111 birds in February.

Project Alone: Construction and Decommissioning

Disturbance and Displacement

123. Direct disturbance and displacement to eider during the construction phase may arise within the Proposed Development export cable corridor (and its immediate vicinity) as a result of increased vessel movements, as well as from other activities directly associated with the installation of the export cable. The Proposed Development array area lies outwith the SPA and no impacts on common eider are predicted to arise within the Proposed Development array area on the basis that no eider were recorded within the area during surveys and the known distribution of eider within the SPA is predominantly coastal (Lawson et al. 2015, SNH 2015, SNH and JNCC 2016).
124. Eider are considered to have a moderate to high sensitivity to such sources of direct disturbance (Goodship and Furness 2022). Reviews of the sensitivity of different seabird species to disturbance from vessels and helicopter traffic assign eider as ‘3’ on a five-scale ranking system (Garthe and Hüppop 2004, Furness et al. 2013, Fliessbach et al. 2019).
125. Studies undertaken indicate that eider may be displaced by vessel traffic with one study reporting eider being flushed by approaching vessels at distances up to 1,000 m and the median distance at which eider did take flight being 208 m (Schwemmer et al. 2011). A similar study reported the maximum distance at which initial disturbance was first recorded amongst flocks of moulting eider was 700 m. with birds taking flight on average at 177 m from a vessel (Dehnhard et al. 2020). Individuals may be more susceptible to disturbance than flocks, with mean disturbance distances reported for individuals as being between 277 21 m and for flocks of 255  195 m (Fliessbach et al. 2019). Goodship and Furness (2022) present buffer zones that indicate the potential range of distances aimed to protect the majority of birds from human disturbance. For common eider during the breeding period the buffer zone is 100 – 200 m and during the non-breeding period 200 – 500 m.
126. Consequently, the area of impact from a single vessel at any one time (based on the maximum non-breeding period buffer zone of 500 m) is 0.78 km2, equivalent to 0.03% of the SPA. During construction there is potential for up to 12 vessels to occur in the area. On this basis a theoretical maximum area of disturbance of up to 9.36 km2 could occur, equivalent to 0.34% of the SPA. However, during construction vessel activity will be clustered around the area of cable laying and therefore the areas of potential disturbance from each vessel will overlap and the overall area of disturbance will be smaller.
127. Not all birds that are disturbed by a vessel necessarily take flight with between 29% and 45% of all observed instance of disturbance not resulting in flight behaviour (Dehnhard et al. 2020, Fliessbach et al. 2019).
128. Eider that are displaced could return to the area following the departure of the vessel. Studies indicate that birds that are displaced will relocate in the wider vicinity with one study reporting a mean distance of 770 m from a vessel (Dehnhard et al. 2020). The number of eider present in an area where displacement has occurred return to the pre-disturbance total within two hours of a vessel departing (Schwemmer et al. 2011). Common eider that are disturbed will return to their pre-disturbance behaviour relatively quickly with reports of 75% of eider returning to previous behaviour within 10 minutes and a maximum of 45 minutes (Dehnhard et al. 2020)
129. Consequently, it is predicted that any disturbance or displacement impacts arising from the construction activities within the SPA will be localised, and temporary with recovery within two hours of the cessation of the activity causing disturbance.
130. The potential for disturbance effects during decommissioning is assumed to be the same (or less) as for construction, noting that the duration of the decommissioning phase will not exceed that of construction, and may be shorter.
131. Recognising the moderate to high sensitivity of eider to disturbance and displacement effects, the relatively small areas that will be subject to activities with the potential to result in disturbance at any given time during the construction period and the fact that these potential effects will be temporary, it is considered that there is no potential for construction or decommissioning related disturbance or displacement to lead to an adverse effect on the Outer Firth of Forth and St Andrews Bay Complex SPA eider population.

Changes to Prey Availability

132. Seaduck (eider, goldeneye, common scoter, velvet scoter and long-tailed duck) feed on a range of prey species but often specialise on one or two prey items (often bivalves or other molluscs) in any one location (e.g. Leopold et al. 2001). However, seaduck are also opportunistic and capable of adjusting diet in response to changes in prey availability or composition (e.g. Forni et al. 2022).
133. During construction there are a number of ways in which effects on key prey species may occur. The installation of infrastructure within the Proposed Development may lead to temporary subtidal habitat loss/disturbance as a result of a range of activities including installation of offshore export cables and associated seabed preparation. Activities will occur intermittently during the construction phase, with only a small proportion of the total footprint affected at any one time. Recovery of seabed habitats will commence immediately following installation of infrastructure allowing key prey species to repopulate the areas of previous disturbance (see volume 2, chapter 9 of the Offshore EIA Report). Furthermore, in intertidal and nearshore subtidal zone the impacts will be limited as the export cables will be buried without trenching out to at least 488 m from the Mean High Water Springs (MHWS). Consequently, there will be no habitat loss or impacts on the availability of prey within this area.
134. Increases in suspended sediment concentrations (SSC) and associated sediment deposition may also reduce the abundance and distribution of prey species. The installation of offshore export cables may result in short-term avoidance of affected areas by fish. Modelling of SSC for installation of inter-array and offshore export cables indicated concentrations of up to 500 mg/l and between 50 mg/l and 500 mg/l, respectively. Most bivalves are known to be tolerant to sediment deposition due to the nature of re-suspension and deposition within their natural high energy environment, and it is therefore very likely that any effect from increased SSC during construction will be limited (volume 2, chapter 9 of the Offshore EIA Report). Furthermore, deposited sediments are expected to be removed quickly by the currents resulting in small amount of sediment being deposited. Given the small amount of predicted deposition, local spatial extent and relatively short duration of predicted SSC increases, no effect on survival of key prey species is predicted (volume 2, chapter 9 of the Offshore EIA Report).
135. Increases in SSC and associated reductions in water clarity may also affect the ability of foraging seaduck to locate prey, reducing the availability of key prey species. However SSC concentrations are likely to be within the range of natural variability (generally <5 mg/l but can increase to over 100 mg/l during storm events/increased wave heights) and will reduce to background concentrations within a very short period (approximately two tidal cycles).
136. Such localised impacts on prey could cause the temporary relocation of eider to unaffected areas, with birds predicted to return once prey abundance recovers to pre-construction levels.
137. Surveys indicate that the export cable route does not occur in an area which is recognised to be significantly important for eider. Therefore any impacts on prey species will only affect a localised area and birds will be able to relocate to areas of suitable habitat and prey availability within the SPA
138. During decommissioning, the effects from changes in prey availability are considered to be the same (or less) as for construction. It is currently unclear as to how the presence, and subsequent removal of, subsea structures may affect prey species (Peschko et al. 2020, BOWL 2021a, BOWL 2021b, Scott, 2022). It is possible that prey abundance could decline from the levels present during the operation and maintenance period. This could occur if the sub-surface structures associated with the Proposed Development in the marine environment lead to an increase in key prey abundance within the Proposed Development array area and export cable corridor via the provision of artificial reef habitats. However, some infrastructure (such as cable protection) is assumed to be left in situ with the impact of colonisation of infrastructure continuing in perpetuity following decommissioning. Thus, any reduction in prey abundance through removal of foundations is likely to be very small relative to foraging areas.
139. It is therefore concluded that any impacts will be temporary and localised during construction and decommissioning and not lead to an adverse effect on the Outer Firth of Forth and St Andrews Bay Complex SPA populations of eider.

Direct Habitat Loss

140. Up to eight export cables will be trenched and buried, each a maximum of 109 km long. It is estimated that impacts from trenching and burying the cable will impact a 15 m wide corridor of seabed and therefore a total of 12.43 km2 of seabed could be disturbed during the trenching and burying of the export cables. It is estimated that approximately 15% of the cable route may need protection, which would be a long-term habitat loss. If this is the case, then an estimated 2.616 km2 of seabed could be lost due to cable protection; equivalent to 0.09% of the total area of the SPA.
141. Export cables will be trenched and buried using either mechanical ploughs or cutters or by high pressure jets depending on the ground conditions. If cable protection is not required, the trenches will be back-filled or backfill naturally over time. The length of time it takes for the trenches to backfill will be dependent on the local seabed conditions and currents.
142. In nearshore intertidal and subtidal waters the export cables will be buried without trenching out at least 488 m from the MHWS mark. Consequently there will be minimal, if any impact, on habitat nearshore.
143. In areas of soft mud or sand, natural infill is predicted to occur rapidly and studies have indicated that infill of trenches can occur at a rate of between 0.2 and 0.5 m every six months, with sediment communities returning to the area of disturbed sediment within 12 months of the cable laying having been undertaken (BERR, 2008). Consequently, the potential impacts from trenching cables within the SPA will be localised and temporary and will not have a long-term impact on the habitat.
144. It is concluded that the very small area of seabed habitat lost within the SPA as a result of cable protection will not cause a significant reduction in the extent, distribution or quality of habitats that support the qualifying species or their prey. The trenching of cables will cause a localised and temporary impact on the habitats within the SPA.
145. Construction activities within the Outer Firth of Forth and St Andrews Bay Complex SPA could cause the loss of habitat which could impact on eider.
146. Eider typically feed in water depths of less than 12 m and therefore their distribution is limited to relatively shallow nearshore water and due to their restricted habitat preferences common eider are considered to have a relatively high sensitivity to loss of habitat. Reviews of the sensitivity of different seabird species to habitat use flexibility assigned eider as ‘4’ on a five-scale ranking system. (Garthe and Hüppop 2004, Furness et al. 2013). Suggesting that eider are sensitive to the loss of habitat.
147. The distribution of eider within the Outer Firth of Forth and St Andrews Bay Complex SPA is predominantly in coastal waters with highest densities occurring in the Tay and inner Firth of Forth. Relatively low densities occur in waters along the export cable corridor (SNH 2015, SNH and JNCC 2016).
148. The potential loss of 0.09% of the SPA due to cable protection and the potential temporary habitat loss caused by trenching and burying the cables will impact on a small proportion of the SPA eider population, which will be able to relocate to other suitable areas until the habitat and associated prey, return to pre-construction levels. The impact will not lead to an adverse effect on the Outer Firth of Forth and St Andrews Bay Complex SPA populations of eider.

Project Alone: Operation and Maintenance

Disturbance and Displacement

149. Direct disturbance and displacement to eider during the operation and maintenance phase may arise within the Proposed Development export cable corridor (and its immediate vicinity) as a result of increased vessel movements.
150. The disturbance and displacement impacts arising from operational and maintenance vessel activity will be similar to or less than that arising during the construction and decommissioning phases. Consequently, it is considered that there is no potential for operational or maintenance related disturbance or displacement to lead to an adverse effect on the Outer Firth of Forth and St Andrews Bay Complex SPA eider population.

Changes to Prey Availability

151. Reduction or disruption to prey availability through temporary and long-term subtidal habitat loss/disturbance, increased SSC and deposition, electromagnetic fields (EMF) from subsea electrical cabling, and colonisation of subsea structures, could affect eider survival and productivity.
152. However, there will be no increase in the potential for temporary changes in prey availability caused by impacts during operating and maintenance phases. Consequently, it is considered that there is no potential for operational or maintenance related changes in prey availability to lead to an adverse effect on the Outer Firth of Forth and St Andrews Bay Complex SPA eider population.

Direct Habitat Loss

153. There will be no increase in direct habitat loss over and above that arising during the construction phase unless unplanned additional cable protection is required over and above the 15% of export cable that is already recognised as might requiring protection under the worst case. If additional protection is required then it is predicted to be a relatively small increase in habitat loss. This will not be required where the cables will be buried without trenching. Consequently, there will be minimal, if any, additional impact on eider through the loss of habitat during the operation and maintenance phase.
154. On this basis it is concluded that the loss of habitat will not lead to an adverse effect on the Outer Firth of Forth and St Andrews Bay Complex SPA populations of eider

Project Alone: Conclusion

155. The potential effects from the Proposed Development alone on the Outer Firth and Forth and St Andrews Bay Complex SPA eider population are predicted to be small and temporary, impacting on a small proportion of the site population. Given this, it is concluded that the effects from the Proposed Development alone would not result in an adverse effect on this SPA population.

Effects In-Combination: Construction, Operation, Maintenance and Decommissioning

Disturbance and Displacement

156. During construction, operation and decommissioning phases there is potential for existing marine traffic activity, including fishing and commercial vessels to cause disturbance and displacement impacts on eider and therefore capable of causing an in-combination impact. Marine traffic occurs widely throughout the region, including within the SPA (see Offshore EIA Report, volume 2, chapter 13) and the additional vessel activity arising during construction, operation and decommissioning will not make any material difference to the level of disturbance and displacement currently present within the SPA. It is predicted that the potential increase in disturbance and displacement would not be detectable against current levels and therefore would not cause an in-combination impact that would lead to an adverse effect on Outer Firth of Forth and St Andrews Bay Complex SPA common eider population.

Changes to Prey Availability

157. There is limited potential for in-combination impacts to affect prey availability within the Outer Firth and Forth and St Andrews Bay Complex SPA. Any impacts will be temporary with recovery following completion of the construction, operation and decommissioning activities. There is limited, if any, potential for in-combination impacts that will cause a measurable effect on the prey of eider and no in-combination impacts that would limit their ability to relocate temporarily to other locations within the SPA where eider are known to occur. Consequently, there will be no in-combination impacts relating to changes in prey availability that would cause an adverse effect on the Outer Firth of Forth and St Andrews Bay Complex SPA eider population.

Direct Habitat Loss

158. Existing and planned offshore wind farms: Inch Cape, Neart na Gaoithe, Seagreen 1 and Seagreen 1A could all have potential to cause in-combination impacts within the SPA (see Offshore EIA Report, volume 2, chapter 8). During construction and decommissioning these impacts will be temporary and in-combination impacts would only occur if activities were undertaken within the SPA simultaneously or overlapping the recovery period. It is predicted that all construction activities for other offshore wind farms that could cause an in-combination impact will be completed prior to the commencement of construction for the proposed Development. There will be in-combination impacts during the operation and maintenance phases of the projects.
159. Potential impacts on habitat from the Proposed Development alone has been identified as being temporary during construction and decommissioning and there is little potential for in-combination impacts to arise with other offshore wind farms due to their construction having been completed before construction commences at the Proposed Development and similarly decommissioning may have been completed by the other projects prior to the start of decommissioning by the proposed Development. There is potential long-term habitat loss throughout the period of operation and maintenance when a potential loss of 0.09% of the SPA could be impacted due to cable protection. The potential long-term loss of habitat associated with the other projects is unknown. However, the long-term loss of habitat from cable protection does not equate to loss of habitat to eider as they do not occur in the area where the majority of impacts on habitat from cable protection are predicted to occur. Furthermore the nearshore trenchless cabling will not impact on the habitats and it is the nearshore areas where eider are known to most frequently occur.
160. The potential impacts on eider will likely be undetectable and will not cause an in-combination impact that would lead to an adverse effect on Outer Firth of Forth and St Andrews Bay Complex SPA eider population.

In-combination: Conclusion

161. The potential effects from the Proposed Development in-combination with other plans or programmes on the Outer Firth and Forth and St Andrews Bay Complex SPA eider population are predicted to be small and temporary, impacting on a small proportion of the site population. Given this, it is concluded that the effects from the Proposed Development in-combination would not result in an adverse effect on this population.

Assessment for the Velvet Scoter Population

162. In Europe velvet scoter breed in Scandinavia, Estonia and Russia and are a winter visitor to the UK.  The UK wintering population is estimated to be approximately 3,350 individuals, with over 2,500 wintering in Scottish coastal waters (Robinson 2005, Forrester et al. 2007). Their distribution in Scottish waters is predominantly along the east coast, with in the Moray Firth, Firth of Tay, St Andrews Bay and the Firth of Forth.
163. The site reference population of 780 individuals has been calculated on multi-year programme of aerial, boat-based and land-based surveys (Lawson et al. 2015). Based on WeBS data the peak mean population size has fluctuated annually but remains largely above the site reference population (Figure 5.2).

Figure 52: Velvet scoter population trend at the Outer Firth of Forth and St Andrews Bay Complex SPA for the period 2001 - 2020. The orange line shows the site reference population size for the SPA (2006/07-2010/11 peak mean of 780 individuals).  Data are from the Wetland Bird Survey Database (BTO 2022).

164. Species specific advice for velvet scoter is:

• Maintain the population of non-breeding velvet scoter at a stable or increasing trend relative to the site reference population.

The Potential for Impacts on the Velvet Scoter Population

165. Potential impacts on the Outer Firth of Forth and St Andrews Bay Complex SPA velvet scoter population screened in for assessment are outlined in section 3 and in the HRA Stage One Screening Report (SSE Renewables, 2021). The assessment of potential barrier and collision impacts on velvet scoter the Firth of Forth SPA are addressed in the Migratory Bird Assessment (Section 5.8).
166. There is potential for temporary changes in prey availability caused by impacts on the habitat arising from construction, operation and decommissioning activities. However, in intertidal and nearshore subtidal zone the impacts will be limited as the export cables will be buried without trenching out to at least 488 m from the MHWS mark. Consequently, there will be no habitat loss or impacts on the availability of prey within this area.
167. No velvet scoter were recorded during any of the site specific surveys undertaken across the Offshore Ornithology Study Area. No velvet scoter were recorded during intertidal and nearshore monthly surveys undertaken at the Skateraw landfall between July 2020 and June 2021.

Project Alone: Construction and Decommissioning

Disturbance and Displacement

168. Direct disturbance and displacement to velvet scoter during the construction phase may arise within the Proposed Development export cable corridor (and its immediate vicinity) as a result of increased vessel movements, as well as from other activities directly associated with the installation of the export cable. The Proposed Development array area lies outwith the SPA and no impacts on velvet scoter are predicted to arise within the Proposed Development array area on the basis that no velvet scoter were recorded within the area during surveys and the known distribution of velvet scoter within the SPA is predominantly coastal (Lawson et al. 2015, SNH 2015, SNH and JNCC 2016).
169. Velvet scoter were not considered in the review of bird sensitivities to disturbance undertaken by Goodship and Furness (2022). Reviews of the sensitivity of different seabird species to disturbance from vessels and helicopter traffic have assessed velvet scoter as having a relative high sensitivity from disturbance arising from vessels (Garthe and Hüppop 2004, Furness et al. 2013, Fliessbach et al. 2019).
170. The Proposed Development offshore export cable encompasses 168 km2 and the total area of Outer Firth of Forth and St Andrews Complex SPA is 2,720.68 km2. Consequently, no more than 6.2% of the SPA will be affected by disturbance over the whole construction phase. Construction activities will not occur simultaneously across the entirety of the Proposed Development export cable corridor but will be undertaken within discrete areas along the cable route corridor.
171. Studies undertaken indicate that velvet scoter may be displaced by vessel traffic with one study reporting velvet scoter being flushed by approaching vessels at distances from between 30 m and 2,000 m (Fliessbach et al. 2019). Consequently, the area of impact from a single vessel at any one time could vary from between 0.002 km2 to 12.56 km2 (based on the minimum and maximum reported disturbance distances), equivalent to between <0.0001% of the SPA and 0.46% of the SPA. During construction there is potential for up to 12 vessels to occur in the area. On this basis a theoretical maximum area of disturbance of up to 150.7 km2 could occur, equivalent to 5.54% of the SPA. However, during construction vessel activity will be clustered around the area of cable laying and therefore the areas of potential disturbance from each vessel will overlap and the overall area of disturbance will be considerably smaller.
172. Velvet scoter that are displaced could return to the area following the departure of the vessel.  Studies indicate that the similar common scoter will return to the area following the departure of the vessel.  However, studies indicate that common scoter that are flushed from an area by a vessel return relatively slowly compared to other seaduck species, with 13% returning within 180 minutes of being disturbed (Schwemmer et al. 2011).
173. Consequently, it is predicted that any disturbance or displacement impacts arising from the construction activities within the SPA will be relatively localised and temporary.
174. The potential for disturbance effects during decommissioning is assumed to be the same (or less) as for construction, noting that the duration of the decommissioning phase will not exceed that of construction, and may be shorter.
175. Recognising that no velvet scoter were recorded during any surveys, the relatively localised areas that will be subject to activities with the potential to result in disturbance at any given time during the construction period and the fact that these potential effects will be temporary, it is considered that there is no potential for construction or decommissioning related disturbance or displacement to lead to an adverse effect on the Outer Firth of Forth and St Andrews Bay Complex SPA velvet scoter population.

Changes to Prey Availability

176. Seaduck (eider, goldeneye, common scoter, velvet scoter and long-tailed duck) feed on a range of prey species but often specialise on one or two prey items (often bivalves or other molluscs) in any one location (e.g. Leopold et al. 2001). However, seaduck are also opportunistic and capable of adjusting diet in response to changes in prey availability or composition (e.g. Forni et al. 2022). 
177. As outlined in the section on project alone: construction and decommissioning – changes to prey availability for eider, there is potential for temporary changes in prey availability caused by impacts on the habitat arising from construction and decommissioning activities. However, in intertidal and nearshore subtidal zone the impacts will be limited as the export cables will be buried without trenching out to at least 488 m from the MHWS. Consequently, there will be no habitat loss or impacts on the availability of prey within this area
178. Any localised impacts on prey could cause the temporary relocation of velvet scoter to unaffected areas, with birds predicted to return once prey abundance recovers to pre-construction levels.
179. Surveys indicate that the export cable route does not occur in an area which is recognised to be significantly important for velvet scoter. Therefore any impacts on prey species will only affect a localised area and birds will be able to relocate to areas of suitable habitat and prey availability within the SPA. Any impacts will be temporary and localised and not lead to an adverse effect on the Outer Firth of Forth and St Andrews Bay Complex SPA populations of velvet scoter.

Direct Habitat Loss

180. Construction activities within the Outer Firth of Forth and St Andrews Bay Complex SPA could cause the loss of habitat which could impact on velvet scoter.
181. Velvet scoter typically feed in water depths of less than 20 m and therefore their distribution is limited to relatively shallow nearshore water (Fox 2003). Reviews of the sensitivity of different seabird species to habitat use flexibility assigned velvet scoter as ‘3’ on a five-scale ranking system. (Furness et al. 2013), suggesting that velvet scoter are moderately sensitive to the loss of habitat.
182. The distribution of velvet scoter within the Outer Firth of Forth and St Andrews Bay Complex SPA is predominantly in coastal waters with highest densities occurring in the Tay and inner Firth of Forth. Relatively low densities occur in waters along the export cable corridor (SNH 2015, SNH and JNCC 2016).
183. The potential loss of 0.09% of the SPA due to cable protection and the potential temporary habitat loss caused by trenching and burying the cables will impact on a small proportion of the SPA velvet scoter population which will be able to relocate to other suitable areas until the habitat and associated prey, return to pre-construction levels. The impact will not lead to an adverse effect on the Outer Firth of Forth and St Andrews Bay Complex SPA populations of velvet scoter.

Project Alone: Operation and Maintenance

Disturbance and Displacement

184. Direct disturbance and displacement to velvet scoter during the operation and maintenance phase may arise within the Proposed Development export cable corridor (and its immediate vicinity) as a result of increased vessel movements.
185. The disturbance and displacement impacts arising from operational and maintenance vessel activity will be similar to or less than that arising during the construction and decommissioning phases. Consequently, it is considered that there is no potential for operational or maintenance related disturbance or displacement to lead to an adverse effect on the Outer Firth of Forth and St Andrews Bay Complex SPA velvet scoter population.

Changes to Prey Availability

186. As outlined in the section on project alone: operation and maintenance – changes to prey availability for eider, there will be no increase in the potential for temporary changes in prey availability caused by impacts during operating and maintenance phases. Consequently, it is considered that there is no potential for operational or maintenance related changes in prey availability to lead to an adverse effect on the Outer Firth of Forth and St Andrews Bay Complex SPA velvet scoter population.

Direct Habitat Loss

187. There will be no increase in direct habitat loss over and above that arising during the construction phase unless un-planned additional cable protection is required over and above the 15% of export cable that is already recognised as might requiring protection. If additional protection is required then it is predicted to be a relatively small increase in habitat loss. This will not be required where the cables will be buried without trenching. Consequently, there will be minimal, if any, additional impact on velvet scoter through the loss of habitat during the operation and maintenance phase.
188. On this basis it is concluded that the loss of habitat during operation and maintenance phase will not lead to an adverse effect on the Outer Firth of Forth and St Andrews Bay Complex SPA populations of velvet scoter.

Project Alone: Conclusion

189. The potential effects from the Proposed Development alone on the Outer Firth and Forth and St Andrews Bay Complex SPA velvet scoter population are predicted to be small and temporary, impacting on a small proportion of the site population. Given this, it is concluded that the effects from the Proposed Development alone would not result in an adverse effect on this population.

Effects In-Combination: Construction, Operation, Maintenance and Decommissioning

Disturbance and Displacement

190. During construction, operation and decommissioning phases there is potential for existing marine traffic activity, including fishing and commercial vessels to cause disturbance and displacement impacts on velvet scoter and therefore capable of causing an in-combination impact. Marine traffic occurs widely throughout the region, including within the SPA (see Offshore EIA report volume 2, chapter 13) and the additional vessel activity arising during construction, operation and decommissioning will not make any material difference to the level of disturbance and displacement currently present within the SPA. It is predicted that the potential increase in disturbance and displacement will not be detectable against current levels and therefore will not cause an in-combination impact that would lead to an adverse effect on Outer Firth of Forth and St Andrews Bay Complex SPA velvet scoter population.

Changes to Prey Availability

191. There is limited potential for in-combination impacts to affect prey availability within the Outer Firth and Forth and St Andrews Bay Complex SPA. Any impacts will be temporary with recovery following completion of the construction, operation and decommissioning activities. There is limited, if any, potential for in-combination impacts that will cause a measurable effect on the prey of velvet scoter and no in-combination impacts that would limit their ability to relocate temporarily to other locations within the SPA where velvet scoter are known to occur. Consequently, there will be no in-combination impacts relating to changes in prey availability that would cause an adverse effect on the Outer Firth of Forth and St Andrews Bay Complex SPA velvet scoter population.

Direct Habitat Loss

192. Existing and planned offshore wind farms: Inch Cape, Neart na Gaoithe, Seagreen 1 and Seagreen 1A could all have potential to cause in-combination impacts within the SPA (see Offshore EIA Report, volume 2, chapter 8). During construction and decommissioning these impacts will be temporary and in-combination impacts would only occur if activities were undertaken within the SPA simultaneously or overlapping the recovery period. It is predicted that all construction activities for other offshore wind farms that could cause an in-combination impact will be completed prior to the commencement of construction for the Proposed Development. There will be in-combination impacts during the operation and maintenance phases of the projects.
193. Potential impacts on habitat from the Proposed Development alone has been identified as being temporary during construction and decommissioning and there is little potential for in-combination impacts to arise with other offshore wind farms due to their construction having been completed before construction commences at the Proposed Development and similarly decommissioning may have been completed by the other projects prior to the start of decommissioning by the proposed Development. There is potential long-term habitat loss throughout the period of operation and maintenance when a potential loss of 0.09% of the SPA could be impacted due to cable protection.  The potential long-term loss of habitat associated with the other projects is unknown. However, the long-term loss of habitat from cable protection does not equate to loss of habitat to velvet scoter as they do not occur in the area where the majority of impacts on habitat from cable protection are predicted to occur. Furthermore the nearshore trenchless cabling will not impact on the habitats and it is the nearshore areas where velvet scoter are known to most frequently occur.
194. The potential impacts on velvet scoter will likely be undetectable and will not cause an in-combination impact that would lead to an adverse effect on Outer Firth of Forth and St Andrews Bay Complex SPA velvet scoter population.

In-combination: Conclusion

195. The potential effects from the Proposed Development in-combination with other plans or programmes on the Outer Firth and Forth and St Andrews Bay Complex SPA velvet scoter population are predicted to be small and temporary, impacting on a small proportion of the site population. Given this, it is concluded that the effects from the Proposed Development in-combination would not result in an adverse effect on this population.

Assessment for the Common Scoter Population

196. Common scoter is a rare breeding bird in the UK, with between 16 and 47 pairs nesting in 2019 (Eaton 2021). The Scottish wintering population is estimated to be between 25,000 and 30,000 individuals (Forrester et al. 2007). Their distribution in Scottish waters is predominantly along the east coast, with in the concentrations occurring Moray Firth, Aberdeenshire, Firth of Tay, St Andrews Bay and the Firth of Forth.
197. The site reference population of 4,700 individuals has been calculated based on a multi-year programme of aerial, boat-based and land-based surveys (Lawson et al. 2015). WeBS data indicates that the peak mean population size has increased above the site reference population since 2016/17 (Figure 5.3).

Figure 53: Common scoter population trend at the Outer Firth of Forth and St Andrews Bay Complex SPA for the period 2001 – 2020. The orange line shows the site reference population size for the SPA (2001/02 – 2004/05 peak mean of 4,700 individuals). Data are from the Wetland Bird Survey Database (BTO 2022).

198. Site specific advice for common scoter is to:

• Maintain the population of non-breeding common scoter at a stable or increasing trend relative to the site reference population.

The Potential for Impacts on the Common Scoter Population

199. Potential impacts on the Outer Firth of Forth and St Andrews Bay Complex SPA common scoter population screened in for assessment are outlined in section 3.1 and in the HRA Stage One Screening Report (SSE Renewables, 2021). The assessment of potential barrier and collision impacts on common scoter the Firth of Forth SPA are addressed in the Migratory Bird Assessment (Section 5.8).
200. Potential impacts from the Proposed Development could arise during construction, operation and maintenance and decommissioning and could cause direct habitat loss, changes in prey availability and disturbance and displacement. Consequently, the focus of the assessment for this SPA population is concerned with all the Conservation Objectives.
201. Three common scoter were recorded within the Proposed Development array area with two in June and one in January. During intertidal and nearshore surveys common scoters were recorded infrequently with typically counts of fewer than 30 individuals. Peak counts of 40 in August 2020 and 47 May 2021 were recorded with all records between 500m and 1 km from shore.

Project Alone: Construction and Decommissioning

Disturbance and Displacement

202. Direct disturbance and displacement to common scoter during the construction phase may arise within the Proposed Development export cable corridor (and its immediate vicinity) as a result of increased vessel movements, as well as from other activities directly associated with the installation of the export cable.
203. Common scoter are considered to be highly sensitive to disturbance from vessels (Goodship and Furness 2022). Reviews of the sensitivity of different seabird species to disturbance from vessels and helicopter traffic have assessed common scoter as having a relative high sensitivity from disturbance arising from vessels (Garthe and Hüppop 2004, Furness et al. 2013, Fliessbach et al. 2019).
204. The Proposed Development offshore export cable encompasses 168 km2 and the total area of Outer Firth of Forth and St Andrews Complex SPA is 2,720.68 km2. Consequently, no more than 6.2% of the SPA will be affected by disturbance over the whole construction phase. Construction activities will not occur simultaneously across the entirety of the Proposed Development export cable corridor but will be undertaken within discrete areas along the cable route corridor.
205. Studies undertaken indicate that common scoter may be displaced by vessel traffic with one study reporting common scoter being flushed by approaching vessels at distances from between 30 m and 2,000 m and for flocks a median distance of 800 m (Fliessbach et al. 2019).
206. Consequently, the area of impact from a single vessel at any one time could vary from between 0.003 km2 to 32.17 km2 (based on the minimum and maximum reported disturbance distances), equivalent to between <0.0001% of the SPA and 1.2% of the SPA. During construction there is potential for up to 12 vessels to occur in the area. On this basis a theoretical maximum area of disturbance of up to 384 km2 could occur, equivalent to 14.1% of the SPA. However, during construction vessel activity will be clustered around the area of cable laying and therefore the areas of potential disturbance from each vessel will overlap and the overall area of disturbance will be considerably smaller.
207. Common scoter that are displaced could return to the area following the departure of the vessel.  However, studies indicate that common scoter that are flushed from an area by a vessel return relatively slowly compared to other seaduck species, with 13% returning within 180 minutes of being disturbed (Schwemmer et al. 2011).
208. Consequently, it is predicted that any disturbance or displacement impacts arising from the construction activities within the SPA could occur over a relatively wide area and although temporary common scoter will return more slowly compared with other species of seaduck.
209. The potential for disturbance effects during decommissioning is assumed to be the same (or less) as for construction, noting that the duration of the decommissioning phase will not exceed that of construction, and may be shorter.
210. The maximum count of 47 common scoter in nearshore and intertidal surveys is 0.77% of the SPA population (based on latest 5 year peak mean) and therefore less than 1% of the SPA population could be temporarily disturbed by vessel activity at any given time during the construction period.  On the basis that the impacts will be temporary, it is considered that there is no potential for construction or decommissioning related disturbance or displacement to lead to an adverse effect on the Outer Firth of Forth and St Andrews Bay Complex SPA common scoter population.

Changes to Prey Availability

211. Seaduck (eider, goldeneye, common scoter, velvet scoter and long-tailed duck) feed on a range of prey species but often specialise on one or two prey items (often bivalves or other molluscs) in any one location (e.g. Leopold et al. 2001). However, seaduck are also opportunistic and capable of adjusting diet in response to changes in prey availability or composition (e.g. Forni et al. 2022).
212. As outlined in the section on project alone: construction and decommissioning – changes to prey availability for eider, there is potential for temporary changes in prey availability caused by impacts on the habitat arising from construction and decommissioning activities. However, in intertidal and nearshore subtidal zone the impacts will be limited as the export cables will be buried without trenching out to at least 488 m from the MHWS. Consequently, there will be no habitat loss or impacts on the availability of prey within this area.
213. Any localised impacts on prey could cause the temporary relocation of common scoter to unaffected areas, with birds predicted to return once prey abundance recovers to pre-construction levels.
214. Surveys indicate that the export cable route does not occur in an area which is recognised to be significantly important for common scoter. Therefore any impacts on prey species will only affect a localised area and birds will be able to relocate to areas of suitable habitat and prey availability within the SPA. Any impacts will be temporary and localised and not lead to an adverse effect on the Outer Firth of Forth and St Andrews Bay Complex SPA populations of common scoter.

Direct Habitat Loss

215. Construction activities within the Outer Firth of Forth and St Andrews Bay Complex SPA could cause the loss of habitat which could impact on common scoter.
216. Common scoter typically feed in water depths of less than 20 m and therefore their distribution is limited to relatively shallow nearshore water (Kaiser et al. 2006). Reviews of the sensitivity of different seabird species to habitat use flexibility assigned common scoter as ‘4’ on a five-scale ranking system. (Furness et al. 2013, Fliessbach et al. 2019). Suggesting that common scoter are moderately to highly sensitive to the loss of habitat.
217. The distribution of common scoter within the Outer Firth of Forth and St Andrews Bay Complex SPA is predominantly in coastal waters with highest densities occurring in the Tay, St Andrews Bay and inner Firth of Forth. Relatively low densities occur in waters along the export cable corridor (SNH 2015, SNH and JNCC 2016).
218. The potential loss of 0.09% of the SPA due to cable protection and the potential temporary habitat loss caused by trenching and burying the cables will impact on a small proportion of the SPA common scoter population which will be able to relocate to other suitable areas until the habitat and associated prey, return to pre-construction levels. The impact will not lead to an adverse effect on the Outer Firth of Forth and St Andrews Bay Complex SPA populations of common scoter.

Project Alone: Operation and Maintenance

Disturbance and Displacement

219. Direct disturbance and displacement to common scoter during the operation and maintenance phase may arise within the Proposed Development export cable corridor (and its immediate vicinity) as a result of increased vessel movements.
220. The disturbance and displacement impacts arising from operational and maintenance vessel activity will be similar to, or less than, that arising during the construction and decommissioning phases. Consequently, it is considered that there is no potential for operational or maintenance related disturbance or displacement to lead to an adverse effect on the Outer Firth of Forth and St Andrews Bay Complex SPA common scoter population.

Changes to Prey Availability

221. There will be no increase in the potential for temporary changes in prey availability caused by impacts during operating and maintenance phases. Consequently, it is considered that there is no potential for operational or maintenance related changes in prey availability to lead to an adverse effect on the Outer Firth of Forth and St Andrews Bay Complex SPA common scoter population.

Direct Habitat Loss

222. There will be no increase in direct habitat loss over and above that arising during the construction phase unless un-planned additional cable protection is required over and above the 15% of export cable that is already recognised as might requiring protection.  If additional protection is required then it is predicted to be a relatively small increase in habitat loss.  This will not be required where the cables will be buried without trenching.  Consequently, there will be minimal, if any, additional impact on common scoter through the loss of habitat during the operation and maintenance phase.
223. On this basis it is concluded that the loss of habitat during operation and maintenance phase will not lead to an adverse effect on the Outer Firth of Forth and St Andrews Bay Complex SPA populations of common scoter.

Project Alone: Conclusion

224. The potential effects from the Proposed Development alone on the Outer Firth and Forth and St Andrews Bay Complex SPA common scoter population are predicted to be small and temporary, impacting on a small proportion of the site population.  Given this, it is concluded that the effects from the Proposed Development alone would not result in an adverse effect on this population.

Effects In-Combination: Construction, Operation, Maintenance and Decommissioning

Disturbance and Displacement

225. During construction, operation and decommissioning phases there is potential for existing marine traffic activity, including fishing and commercial vessels to cause disturbance and displacement impacts on common scoter and therefore capable of causing an in-combination impact.  Marine traffic occurs widely throughout the region, including within the SPA (see Offshore EIA report, volume 2, chapter 13) and the additional vessel activity arising during construction, operation and decommissioning will not make any material difference to the level of disturbance and displacement currently present within the SPA. It is predicted that the potential increase in disturbance and displacement will not be detectable against current levels and therefore will not cause an in-combination impact that would lead to an adverse effect on Outer Firth of Forth and St Andrews Bay Complex SPA common scoter population.

Changes to Prey Availability

226. As outlined in the section on project alone: operation and maintenance – changes to prey availability for eider, there is limited potential for in-combination impacts to affect prey availability within the Outer Firth and Forth and St Andrews Bay Complex SPA. Any impacts will be temporary with recovery following completion of the construction, operation and decommissioning activities.  There is limited, if any, potential for in-combination impacts that will cause a measurable effect on the prey of common scoter and no in-combination impacts that would limit their ability to relocate temporarily to other locations within the SPA where common scoter are known to occur. Consequently, there will be no in-combination impacts relating to changes in prey availability that would cause an adverse effect on the Outer Firth of Forth and St Andrews Bay Complex SPA common scoter population.

Direct Habitat Loss

227. Existing and planned offshore wind farms: Inch Cape, Neart na Gaoithe, Seagreen 1 and Seagreen 1A could all have potential to cause in-combination impacts within the SPA (See Offshore EIA Report, volume 2, chapter 8).  During construction and decommissioning these impacts will be temporary and in-combination impacts would only occur if activities were undertaken within the SPA simultaneously or overlapping the recovery period.  It is predicted that all construction activities for other offshore wind farms that could cause an in-combination impact will be completed prior to the commencement of construction for the proposed Development.  There will be in-combination impacts during the operation and maintenance phases of the projects.
228. Potential impacts on habitat from the Project Alone has been identified as being temporary during construction and decommissioning and there is little potential for in-combination impacts to arise with other offshore wind farms due to their construction having been completed before construction commences at the Proposed Development and similarly decommissioning may have been completed by the other projects prior to the start of decommissioning by the proposed Development.  There is potential long-term habitat loss throughout the period of operation and maintenance when a potential loss of 0.09% of the SPA could be impacted due to cable protection.  The potential long-term loss of habitat associated with the other projects is unknown.  However, the long-term loss of habitat from cable protection does not equate to loss of habitat to common scoter as they do not occur in the area where the majority of impacts on habitat from cable protection are predicted to occur. Furthermore the nearshore trenchless cabling will not impact on the habitats and it is the nearshore areas where common scoter are known to most frequently occur.
229. The potential impacts on common scoter will likely be undetectable and will not cause an in-combination impact that would lead to an adverse effect on Outer Firth of Forth and St Andrews Bay Complex SPA common scoter population.

In-combination: Conclusion

230. The potential effects from the Proposed Development in-combination with other plans or programmes on the Outer Firth and Forth and St Andrews Bay Complex SPA common scoter population are predicted to be small and temporary, impacting on a small proportion of the site population.  Given this, it is concluded that the effects from the Proposed Development in-combination would not result in an adverse effect on this population.

Assessment for the Long-tailed Duck Population

231. Long-tailed duck is a winter visitor to the UK with the first birds returning in September and the winter population peaking between December and February.  The Scottish wintering population estimated to be about 15,000 individuals (Forrester et al. 2007).  They are widely distributed in waters around Scotland with the highest population estimated to occur in the Moray Firth.
232. The site reference population of 1,950 individuals has been calculated based on a multi-year programme of aerial, boat-based and land-based surveys (Lawson et al. 2015).  WeBS data indicates that the peak mean population size has increased above the site reference population since 2016/17 (Figure 5.4).
233. The five year peak mean population size decreased between 2001 and 2010 but has since remained relatively stable (Figure 5.4).

Figure 54: Long-tailed duck population trend at the Outer Firth of Forth and St Andrews Bay Complex SPA for the period 2001 - 2020. The orange line shows the site reference population size for the SPA (2001/02 – 2004/05 peak mean of 1,950 individuals). Data are from the Wetland Bird Survey Database (BTO 2022).

234. Species specifc advice in relation to long-tailed duck is to:

• Maintain the population of non-breeding long-tailed ducks at a stable or increasing trend relative to the site reference population.
• Maintain the variety and abundance of food resources and the condition of supporting habitats and associated processes.
• Existing water quality should be maintained and any increase in nutrients, turbidity or contaminants where this could reduce supporting habitats and/or prey, should be avoided.

The Potential for Impacts on the Long-tailed Duck Population

235. Potential impacts on the Outer Firth of Forth and St Andrews Bay Complex SPA long-tailed duck population screened in for assessment are outlined in section 3.1 and in the HRA Stage One Screening Report (SSE Renewables, 2021). The assessment of potential barrier and collision impacts on long-tailed duck the Firth of Forth SPA are addressed in the Migratory Bird Assessment (Section 5.8).
236. Potential impacts from the Proposed Development could arise during construction, operation and maintenance and decommissioning and could cause direct habitat loss, changes in prey availability and disturbance and displacement.  Consequently, the focus of the assessment for this SPA population is concerned with all the Conservation Objectives.
237. No long-tailed duck were recorded within the Proposed Development array area.  During intertidal and nearshore surveys single long-tailed ducks were recorded on three occasions between December 2020 and March 2021.

Project Alone: Construction and Decommissioning

Disturbance and Displacement

238. Direct disturbance and displacement to long-tailed duck during the construction phase may arise within the Proposed Development export cable corridor (and its immediate vicinity) as a result of increased vessel movements and helicopter activity, as well as from other activities directly associated with the installation of the export cable. The Proposed Development array area lies outwith the SPA and no impacts on long-tailed duck are predicted to arise within the Proposed Development array area on the basis that no long-tailed duck were recorded within the area during surveys and the known distribution of long-tailed duck within the SPA is predominantly coastal (Lawson et al. 2015, SNH 2015, SNH and JNCC 2016).
239. Reviews of the sensitivity of different seabird species to disturbance from vessels have assessed long-tailed duck as having a moderate sensitivity from disturbance arising from vessels and the lowest sensitivity of all the seaduck species considered within the reviews (Furness et al. 2013, Fliessbach et al. 2019). However, studies undertaken in Orkney reported long-tailed duck to be sensitive to vessel disturbance with a high propensity to fly away from marine vessels (Jarrett et al. 2018, 2022).
240. The Proposed Development offshore export cable encompasses 168 km2 and the total area of Outer Firth of Forth and St Andrews Complex SPA is 2,720.68 km2. Consequently, no more than 6.2% of the SPA will be affected by disturbance over the whole construction phase.  Construction activities will not occur simultaneously across the entirety of the Proposed Development export cable corridor but will be undertaken within discrete areas along the cable route corridor.
241. Studies undertaken indicate that long-tailed duck may be displaced by vessel traffic with one study reporting long-tailed duck being flushed by approaching vessels at distances from between 10 m and 1,500 m and for flocks a median distance of 250 m (Fliessbach et al. 2019).  Flight distances of at least 400 m were reported for long-tailed ducks disturbed by vessel activity in Orkney (Jarrett et al. 2018, 2022).
242. Consequently, the area of impact from a single vessel at any one time could vary from between 0.0003 km2 to 7.07 km2 (based on the minimum and maximum reported disturbance distances), equivalent to between <0.0001% of the SPA and 0.26% of the SPA. During construction there is potential for up to 12 vessels to occur in the area.  On this basis a theoretical maximum area of disturbance of up to 84.8 km2 could occur, equivalent to 3.11% of the SPA.  However, during construction vessel activity will be clustered around the area of cable laying and therefore the areas of potential disturbance from each vessel will overlap and the overall area of disturbance will be considerably smaller.
243. Long-tailed duck that are displaced could return to the area following the departure of the vessel.  with, studies reporting numbers returning to pre-disturbance levels within 180 minutes of the vessel disturbance occurring (Schwemmer et al. 2011).
244. Consequently, it is predicted that any disturbance or displacement impacts arising from the construction activities within the SPA would occur over a relatively localised area and be temporary with long-tailed duck returning to the area within relatively short period of time.
245. The potential for disturbance effects during decommissioning is assumed to be the same (or less) as for construction, noting that the duration of the decommissioning phase will not exceed that of construction, and may be shorter.
246. The maximum count of 3 long-tailed duck in nearshore and intertidal surveys is 1.1% of the SPA population (based on latest 5 year peak mean). However, the impacts from disturbance or displacement caused by vessel activity will be temporary and localised and it is considered that there is no potential for construction or decommissioning related disturbance or displacement that would lead to an adverse effect on the Outer Firth of Forth and St Andrews Bay Complex SPA long-tailed duck population.

Changes to Prey Availability

247. Long-tailed duck feed a wide range of prey items including bivalves, gastropods and crustaceans and habitats capable of supporting suitable prey items occur widely across the SPA (NatureScot and JNCC 2022). Although construction and decommissioning activities could cause a localised impact on prey within the SPA. The impacts are predicted to be temporary with benthic communities predicted to recover following cessation of activities. 
248. As outlined in the section on project alone: construction and decommissioning – changes to prey availability for eider, there is potential for temporary changes in prey availability caused by impacts on the habitat arising from construction and decommissioning activities. However, in intertidal and nearshore subtidal zone the impacts will be limited as the export cables will be buried without trenching out to at least 488 m from the MHWS. Consequently, there will be no habitat loss or impacts on the availability of prey within this area.
249. Any localised impacts on prey could cause the temporary relocation of long-tailed duck to unaffected areas, with birds predicted to return once prey abundance recovers to pre-construction levels.
250. Surveys indicate that the export cable route does not occur in an area which is recognised to be significantly important for long-tailed duck. Therefore any impacts on prey species will only affect a localised area and birds will be able to relocate to areas of suitable habitat and prey availability within the SPA.  Any impacts will be temporary and localised and not lead to an adverse effect on the Outer Firth of Forth and St Andrews Bay Complex SPA populations of Long-tailed duck.

Direct Habitat Loss

251. Construction activities within the Outer Firth of Forth and St Andrews Bay Complex SPA could cause the loss of habitat which could impact on long-tailed duck.
252. Reviews of the sensitivity of different seabird species to habitat use flexibility assigned long-tailed duck as ‘4’ on a five-scale ranking system. (Furness et al. 2013, Fliessbach et al. 2019). Suggesting that long-tailed duck are moderately to highly sensitive to the loss of habitat.
253. The distribution of long-tailed duck within the Outer Firth of Forth and St Andrews Bay Complex SPA have their highest concentrations in the Firth of Tay and the northern and central sections of the Firth of Forth. Relatively low densities occur in waters along the export cable corridor (NatureScot and JNCC 2022, SNH 2015, SNH and JNCC 2016).
254. The potential loss of 0.09% of the SPA due to cable protection and the potential temporary habitat loss caused by trenching and burying the cables will impact on a small proportion of the SPA long-tailed duck population which will be able to relocate to other suitable areas until the habitat and associated prey, return to pre-construction levels. The impact will not lead to an adverse effect on the Outer Firth of Forth and St Andrews Bay Complex SPA populations of long-tailed duck.

Project Alone: Operation and Maintenance

Disturbance and Displacement

255. Direct disturbance and displacement to long-tailed duck during the operation and maintenance phase may arise within the Proposed Development export cable corridor (and its immediate vicinity) as a result of increased vessel movements.
256. The disturbance and displacement impacts arising from operational and maintenance vessel activity will be similar to, or less than, that arising during the construction and decommissioning phases.  Consequently, it is considered that there is no potential for operational or maintenance related disturbance or displacement to lead to an adverse effect on the Outer Firth of Forth and St Andrews Bay Complex SPA long-tailed duck population.

Changes to Prey Availability

257. As outlined in the section on project alone: operation and maintenance – changes to prey availability for eider, there will be no increase in the potential for temporary changes in prey availability caused by impacts during operating and maintenance phases. Consequently, it is considered that there is no potential for operational or maintenance related changes in prey availability to lead to an adverse effect on the Outer Firth of Forth and St Andrews Bay Complex SPA long-tailed duck population.

Direct Habitat Loss

258. There will be no increase in direct habitat loss over and above that arising during the construction phase unless un-planned additional cable protection is required over and above the 15% of export cable that is already recognised as might requiring protection.  If additional protection is required then it is predicted to be a relatively small increase in habitat loss.  This will not be required where the cables will be buried without trenching.  Consequently, there will be minimal, if any, additional impact on long-tailed duck through the loss of habitat during the operation and maintenance phase.
259. On this basis it is concluded that the loss of habitat during operation and maintenance phase will not lead to an adverse effect on the Outer Firth of Forth and St Andrews Bay Complex SPA populations of long-tailed duck.

Project Alone: Conclusion

260. The potential effects from the Proposed Development alone on the Outer Firth and Forth and St Andrews Bay Complex SPA long-tailed duck population are predicted to be small and temporary, impacting on a small proportion of the site population.  Given this, it is concluded that the effects from the Proposed Development alone would not result in an adverse effect on this population.

Effects In-Combination: Construction, Operation, Maintenance and Decommissioning

Disturbance and Displacement

261. During construction, operation and decommissioning phases there is potential for existing marine traffic activity, including fishing and commercial vessels to cause disturbance and displacement impacts on long-tailed duck and therefore capable of causing an in-combination impact.  Marine traffic occurs widely throughout the region, including within the SPA (see Offshore EIA report volume 2, chapter 13) and the additional vessel activity arising during construction, operation and decommissioning will not make any material difference to the level of disturbance and displacement currently present within the SPA. It is predicted that the potential increase in disturbance and displacement will not be detectable against current levels and therefore will not cause an in-combination impact that would lead to an adverse effect on Outer Firth of Forth and St Andrews Bay Complex SPA long-tailed duck population.

Changes to Prey Availability

262. There is limited potential for in-combination impacts to affect prey availability within the Outer Firth and Forth and St Andrews Bay Complex SPA. Any impacts will be temporary with recovery following completion of the construction, operation and decommissioning activities.  There is limited, if any, potential for in-combination impacts that will cause a measurable effect on the prey of long-tailed duck and no in-combination impacts that would limit their ability to relocate temporarily to other locations within the SPA where long-tailed duck are known to occur. Consequently, there will be no in-combination impacts relating to changes in prey availability that would cause an adverse effect on the Outer Firth of Forth and St Andrews Bay Complex SPA long-tailed duck population.

Direct Habitat Loss

263. Existing and planned offshore wind farms: Inch Cape, Neart na Gaoithe, Seagreen 1 and Seagreen 1A could all have potential to cause in-combination impacts within the SPA (See Offshore EIA Report, volume 2, chapter 8).  During construction and decommissioning these impacts will be temporary and in-combination impacts would only occur if activities were undertaken within the SPA simultaneously or overlapping the recovery period.  It is predicted that all construction activities for other offshore wind farms that could cause an in-combination impact will be completed prior to the commencement of construction for the Proposed Development.  There will be in-combination impacts during the operation and maintenance phases of the projects.
264. Potential impacts on habitat from the project alone has been identified as being temporary during construction and decommissioning and there is little potential for in-combination impacts to arise with other offshore wind farms due to their construction having been completed before construction commences at the Proposed Development and similarly decommissioning may have been completed by the other projects prior to the start of decommissioning by the proposed Development.  There is potential long-term habitat loss throughout the period of operation and maintenance when a potential loss of 0.09% of the SPA could be impacted due to cable protection.  The potential long-term loss of habitat associated with the other projects is unknown.  However, the long-term loss of habitat from cable protection does not equate to loss of habitat to long-tailed duck as they do not occur in the area where the majority of impacts on habitat from cable protection are predicted to occur. Furthermore the nearshore trenchless cabling will not impact on the habitats and it is the nearshore areas where long-tailed duck are known to most frequently occur.
265. The potential impacts on long-tailed duck will likely be undetectable and will not cause an in-combination impact that would lead to an adverse effect on Outer Firth of Forth and St Andrews Bay Complex SPA long-tailed duck population.

In-combination: Conclusion

266. The potential effects from the Proposed Development in-combination with other plans or programmes on the Outer Firth and Forth and St Andrews Bay Complex SPA long-tailed duck population are predicted to be small and temporary, impacting on a small proportion of the site population.  Given this, it is concluded that the effects from the Proposed Development in-combination would not result in an adverse effect on this population.

Assessment for the Goldeneye Population

267. Goldeneye is a rare breeding bird in the UK with an estimated breeding population of less than 200 pairs, of which approximately 150 pairs breed in Scotland (Woodward et al. 2020, Forrester et al. 2007).  The Scottish wintering population is estimated to be between 10,000 and 12,000 individuals (Forrester et al. 2007).  They are widely distributed in waters around Scotland with the highest wintering population occurring in the Firth of Forth with over 1,300 individuals counted in winter 2019/2020 (BTO 2022). Goldeneye winter in the SPA from between September and mid-April (NatureScot and JNCC 2022).
268. The site reference population of 590 individuals has been calculated based on a multi-year programme of aerial, boat-based and land-based surveys (Lawson et al. 2015).  WeBS data indicates that the peak mean population size has remained above the site reference population since at least 2001 (Figure 5.5).

Figure 55: Goldeneye population trend at the Outer Firth of Forth and St Andrews Bay Complex SPA for the period 2001 - 2020. The orange line shows the site reference population size for the SPA (2006/07-2010/11 peak mean of 590 individuals). Data are from the Wetland Bird Survey Database (BTO 2022).

269. Species specifc advice for goldeneye is to:

• Maintain the population of non-breeding goldeneye at a stable or increasing trend relative to the site reference population.

Potential Impacts on the Goldeneye Population

270. Potential impacts on the Outer Firth of Forth and St Andrews Bay Complex SPA goldeneye population screened in for assessment are outlined in section 3.1 and in the HRA Stage One Screening Report (SSE Renewables, 2021). The assessment of potential barrier and collision impacts on goldeneye in the Firth of Tay and Eden estuary SPA and the Firth of Forth SPA are addressed in the Migratory Bird Assessment (Section 5.8).
271. Potential impacts from the Proposed Development could arise during construction, operation and maintenance and decommissioning and could cause direct habitat loss, changes in prey availability and disturbance and displacement.  Consequently, the focus of the assessment for this SPA population is concerned with all the Conservation Objectives.
272. No goldeneye were recorded within the Proposed Development array area.  During intertidal and nearshore surveys goldeneye were recorded intermittently, predominantly during the winter and passage months in relatively low numbers of no more than seven in all surveyed sectors. The peak count of seven was recorded in February 2021. Almost all birds were recorded within 500 m of the shore.

Project Alone: Construction and Decommissioning

Disturbance and Displacement

273. Direct disturbance and displacement to goldeneye during the construction phase may arise within the Proposed Development export cable corridor (and its immediate vicinity) as a result of increased vessel movements, as well as from other activities directly associated with the installation of the export cable. The Proposed Development array area lies outwith the SPA and no impacts on goldeneye are predicted to arise within the Proposed Development array area as none were recorded there during surveys.
274. Reviews of the sensitivity of different seabird species to disturbance from vessels have assessed goldeneye as having a moderate to high sensitivity from disturbance arising from vessels (Furness et al. 2013) and a high sensitivity from more general disturbance (Goodship and Furness 2022).
275. The Proposed Development offshore export cable encompasses 168 km2 and the total area of Outer Firth of Forth and St Andrews Complex SPA is 2,720.68 km2. Consequently, no more than 6.2% of the SPA will be affected by disturbance over the whole construction phase.  Construction activities will not occur simultaneously across the entirety of the Proposed Development export cable corridor but will be undertaken within discrete areas along the cable route corridor.
276. There are limited studies on the impacts from marine vessel traffic on goldeneye.  Goodship and Furness (2022) suggest a disturbance buffer of between 150 m and 800 m.
277. Consequently, the area of impact from a single vessel at any one time could vary from between 0.07 km2 to 2.01 km2 (based on the minimum and maximum suggested buffer distances), equivalent to between <0.002% of the SPA and 0.07% of the SPA. During construction there is potential for up to 12 vessels to occur in the area.  On this basis a theoretical maximum area of disturbance of up to 24 km2 could occur, equivalent to 0.88% of the SPA.  However, during construction vessel activity will be clustered around the area of cable laying and therefore the areas of potential disturbance from each vessel will overlap and the overall area of disturbance will be considerably smaller.
278. Goldeneye that are displaced could return to the area following the departure of the vessel, although the duration that the displacement caused by a marine vessel is unknown for all other seaduck species for which there are data, it is shown that displacement effects caused by marine vessel traffic are always temporary.  Consequently, it is predicted that any disturbance or displacement impacts arising from the construction activities within the SPA would occur over a relatively localised area and be temporary with goldeneye returning to the area once activities have ceased.
279. The potential for disturbance effects during decommissioning is assumed to be the same (or less) as for construction, noting that the duration of the decommissioning phase will not exceed that of construction, and may be shorter.
280. The maximum count of seven goldeneye in nearshore and intertidal surveys is 0.4% of the SPA population (based on latest 5 year peak mean). Any disturbance impacts will be temporary and localised and it is considered that there is no potential for construction or decommissioning related disturbance or displacement to lead to an adverse effect on the Outer Firth of Forth and St Andrews Bay Complex SPA goldeneye population.

Changes to Prey Availability

281. Seaduck (eider, goldeneye, common scoter, velvet scoter and long-tailed duck) feed on a range of prey species but often specialise on one or two prey items (often bivalves or other molluscs) in any one location (e.g. Leopold et al. 2001). However, seaduck are also opportunistic and capable of adjusting diet in response to changes in prey availability or composition (e.g. Forni et al. 2022).
282. As outlined in the section on project alone: construction and decommissioning – changes to prey availability for eider, there is potential for temporary changes in prey availability caused by impacts on the habitat arising from construction and decommissioning activities. However, in intertidal and nearshore subtidal zone the impacts will be limited as the export cables will be buried without trenching out to at least 488 m from the MHWS. Consequently, there will be no habitat loss or impacts on the availability of prey within this area.
283. Any localised impacts on prey could cause the temporary relocation of goldeneye to unaffected areas, with birds predicted to return once prey abundance recovers to pre-construction levels.
284. Surveys indicate that the export cable route does not occur in an area which is recognised to be significantly important for goldeneye. Therefore any impacts on prey species will only affect a localised area and birds will be able to relocate to areas of suitable habitat and prey availability within the SPA.  Any impacts will be temporary and localised and not lead to an adverse effect on the Outer Firth of Forth and St Andrews Bay Complex SPA populations of goldeneye.

Direct Habitat Loss

285. Construction activities within the Outer Firth of Forth and St Andrews Bay Complex SPA could cause the loss of habitat which could impact on goldeneye.
286. Reviews of the sensitivity of different seabird species to habitat use flexibility assigned goldeneye as ‘4’ on a five-scale ranking system. (Furness et al. 2013). Suggesting that goldeneye are moderately to highly sensitive to the loss of habitat.
287. The distribution of goldeneye within the Outer Firth of Forth and St Andrews Bay Complex SPA is almost exclusively in nearshore waters within the Firth of Forth, with low numbers elsewhere (NatureScot and JNCC 2022, SNH 2015, SNH and JNCC 2016). 
288. The potential loss of 0.09% of the SPA due to cable protection and the potential temporary habitat loss caused by trenching and burying the cables will impact on a small proportion of the SPA goldeneye population which will be able to relocate to other suitable areas until the habitat and associated prey, return to pre-construction levels. The impact will not lead to an adverse effect on the Outer Firth of Forth and St Andrews Bay Complex SPA populations of long-tailed duck.

Project Alone: Operation and Maintenance

Disturbance and Displacement

289. Direct disturbance and displacement to goldeneye during the operation and maintenance phase may arise within the Proposed Development export cable corridor (and its immediate vicinity) as a result of increased vessel movements and helicopter activity.
290. The disturbance and displacement impacts arising from operational and maintenance vessel activity will be similar to, or less than, that arising during the construction and decommissioning phases.  Consequently, it is considered that there is no potential for operational or maintenance related disturbance or displacement to lead to an adverse effect on the Outer Firth of Forth and St Andrews Bay Complex SPA goldeneye population.

Changes to Prey Availability

291. As outlined in the section on project alone: operation and maintenance – changes to prey availability for eider, there will be no increase in the potential for temporary changes in prey availability caused by impacts during operating and maintenance phases. Consequently, it is considered that there is no potential for operational or maintenance related changes in prey availability to lead to an adverse effect on the Outer Firth of Forth and St Andrews Bay Complex SPA goldeneye population.

Direct Habitat Loss

292. There will be no increase in direct habitat loss over and above that arising during the construction phase unless un-planned additional cable protection is required over and above the 15% of export cable that is already recognised as might requiring protection.  If additional protection is required then it is predicted to be a relatively small increase in habitat loss.  This will not be required where the cables will be buried without trenching.  Consequently, there will be minimal, if any, additional impact on goldeneye through the loss of habitat during the operation and maintenance phase.
293. On this basis it is concluded that the loss of habitat during operation and maintenance phase will not lead to an adverse effect on the Outer Firth of Forth and St Andrews Bay Complex SPA populations of goldeneye.

Project Alone: Conclusion

294. The potential effects from the Proposed Development alone on the Outer Firth and Forth and St Andrews Bay Complex SPA goldeneye population are predicted to be small and temporary, impacting on a small proportion of the site population.  Given this, it is concluded that the effects from the Proposed Development alone would not result in an adverse effect on this population.

Effects In-Combination: Construction, Operation, Maintenance and Decommissioning

Disturbance and Displacement

295. During construction, operation and decommissioning phases there is potential for existing marine traffic activity, including fishing and commercial vessels to cause disturbance and displacement impacts on goldeneye and therefore capable of causing an in-combination impact.  Marine traffic occurs widely throughout the region, including within the SPA (see Offshore EIA report, volume 2, chapter 13) and the additional vessel activity arising during construction, operation and decommissioning will not make any material difference to the level of disturbance and displacement currently present within the SPA. It is predicted that the potential increase in disturbance and displacement will not be detectable against current levels and therefore will not cause an in-combination impact that would lead to an adverse effect on Outer Firth of Forth and St Andrews Bay Complex SPA goldeneye population.

Changes to Prey Availability

296. There is limited potential for in-combination impacts to affect prey availability within the Outer Firth and Forth and St Andrews Bay Complex SPA. Any impacts will be temporary with recovery following completion of the construction, operation and decommissioning activities.  There is limited, if any, potential for in-combination impacts that will cause a measurable effect on the prey of goldeneye and no in-combination impacts that would limit their ability to relocate temporarily to other locations within the SPA where goldeneye are known to occur. Consequently, there will be no in-combination impacts relating to changes in prey availability that would cause an adverse effect on the Outer Firth of Forth and St Andrews Bay Complex SPA goldeneye population.

Direct Habitat Loss

297. Existing and planned offshore wind farms: Inch Cape, Neart na Gaoithe, Seagreen 1 and Seagreen 1A could all have potential to cause in-combination impacts within the SPA (See Offshore EIA Report, volume 2, chapter 8).  During construction and decommissioning these impacts will be temporary and in-combination impacts would only occur if activities were undertaken within the SPA simultaneously or overlapping the recovery period.  It is predicted that all construction activities for other offshore wind farms that could cause an in-combination impact will be completed prior to the commencement of construction for the proposed Development.  There will be in-combination impacts during the operation and maintenance phases of the projects.
298. Potential impacts on habitat from the Project Alone has been identified as being temporary during construction and decommissioning and there is little potential for in-combination impacts to arise with other offshore wind farms due to their construction having been completed before construction commences at the Proposed Development and similarly decommissioning may have been completed by the other projects prior to the start of decommissioning by the proposed Development.  There is potential long-term habitat loss throughout the period of operation and maintenance when a potential loss of 0.09% of the SPA could be impacted due to cable protection.  The potential long-term loss of habitat associated with the other projects is unknown.  However, the long-term loss of habitat from cable protection does not equate to loss of habitat to goldeneye as they do not occur in the area where the majority of impacts on habitat from cable protection are predicted to occur. Furthermore the nearshore trenchless cabling will not impact on the habitats and it is the nearshore areas where goldeneye are known to most frequently occur.
299. The potential impacts on goldeneye will likely be undetectable and will not cause an in-combination impact that would lead to an adverse effect on Outer Firth of Forth and St Andrews Bay Complex SPA goldeneye population.

In-combination: Conclusion

300. The potential effects from the Proposed Development in-combination with other plans or programmes on the Outer Firth and Forth and St Andrews Bay Complex SPA goldeneye population are predicted to be small and temporary, impacting on a small proportion of the site population.  Given this, it is concluded that the effects from the Proposed Development in-combination would not result in an adverse effect on this population.

Assessment for the Red-breasted Merganser Population

301. Potential impacts on the Outer Firth of Forth and St Andrews Bay Complex SPA red-breasted merganser population screened in for assessment are outlined in section 3.1 and in the HRA Stage One Screening Report (SSE Renewables, 2021). The assessment of potential barrier and collision impacts on red-breasted merganser  in the Firth of Tay and Eden estuary SPA and the Firth of Forth SPA are addressed in the Migratory Bird Assessment (Section 5.8).
302. Red-breasted merganser is a rare breeding bird in the UK, with between 16 and 47 pairs nesting in 2019 (Eaton 2021).  The Scottish wintering population is estimated to be between 25,000 and 30,000 individuals (Forrester et al. 2007).  Their distribution in Scottish waters is widespread occurring across both east and west coasts.  Along the east coast highest numbers in recent years have occurred in the Firth of Forth, Inner Moray and Beauly Firths and the Montrose Basin.
303. The site reference population of 430 individuals has been calculated based on a multi-year programme of aerial, boat-based and land-based surveys (Lawson et al. 2015).  WeBS data indicates that the peak mean population size has fluctuated but remained above the site reference population since at least 2001 (Figure 5.6).

Figure 56: Red-breasted merganser population trend at the Outer Firth of Forth and St Andrews Bay Complex SPA for the period 2001 - 2020. The orange line shows the citation population size for the SPA (2006/07-2010/11 peak mean of 430 individuals). Data are from the Wetland Bird Survey Database (BTO 2022).

304. Species specific advice in relation to red-breasted merganser is to:

• Maintain the population of non-breeding red-breasted mergansers at a stable or increasing trend relative to the site reference population
• Ensure red-breasted mergansers can move safely between the site and important areas of functionally linked land outwith the site.

Potential Impacts on the Red-breasted Merganser Population

305. Potential impacts from the Proposed Development could arise during construction, operation and maintenance and decommissioning and could cause direct habitat loss, changes in prey availability and disturbance and displacement.  Consequently, the focus of the assessment for this SPA population is concerned with all the Conservation Objectives.
306. No red-breasted merganser were recorded within the Proposed Development array area.  During intertidal and nearshore surveys no more than five individuals were recorded during any month.  Almost all birds were recorded within 500 m of the shore. 

Project Alone: Construction and Decommissioning

Disturbance and Displacement

307. Direct disturbance and displacement to red-breasted merganser during the construction phase may arise within the Proposed Development export cable corridor (and its immediate vicinity) as a result of increased vessel movements, as well as from other activities directly associated with the installation of the export cable.
308. Reviews of the sensitivity of different seabird species to disturbance from vessels have assessed red-breasted merganser as having a relative high sensitivity from disturbance arising from vessels (Fliessbach et al. 2019).
309. The Proposed Development offshore export cable encompasses 168 km2 and the total area of Outer Firth of Forth and St Andrews Complex SPA is 2,720.68 km2. Consequently, no more than 6.2% of the SPA will be affected by disturbance over the whole construction phase.  Construction activities will not occur simultaneously across the entirety of the Proposed Development export cable corridor but will be undertaken within discrete areas along the cable route corridor.
310. Studies undertaken indicate that red-breasted merganser may be displaced by vessel traffic with one study reporting individuals being flushed by approaching vessels at distances from between 120 m and 2,000 m and for flocks a median distance of 500 m (Fliessbach et al. 2019).
311. Consequently, the area of impact from a single vessel at anyone time could vary from between 0.07 km2 to 32.17 km2 (based on the minimum and maximum reported disturbance distances), equivalent to between <0.002% of the SPA and 1.2% of the SPA. During construction there is potential for up to 12 vessels to occur in the area.  On this basis a theoretical maximum area of disturbance of up to 386 km2 could occur, equivalent to 14.2% of the SPA.  However, during construction vessel activity will be clustered around the area of cable laying and therefore the areas of potential disturbance from each vessel will overlap and the overall area of disturbance will be considerably smaller.
312. Red-breasted merganser that are displaced could return to the area following the departure of the vessel.  With studies reporting no significant changes in the numbers of birds present within 30 minutes of disturbance occurring (Jarrett et al. 2018).
313. Consequently, it is predicted that any disturbance or displacement impacts arising from the construction activities within the SPA could occur over a relatively wide area but will be temporary and localised with no significant changes in the numbers present.
314. The potential for disturbance effects during decommissioning is assumed to be the same (or less) as for construction, noting that the duration of the decommissioning phase will not exceed that of construction, and may be shorter.
315. The maximum count of five red-breasted mergansers in nearshore and intertidal surveys is 1.0% of the SPA population (based on latest five year peak mean) and therefore an estimated 1% of the SPA red-breasted merganser population could be temporarily disturbed by vessel activity at any given time during the construction period. However, on the basis that the impacts will be temporary and localised and will not cause change in the abundance within the SPA, it is considered that there is no potential for construction or decommissioning related disturbance or displacement to lead to an adverse effect on the Outer Firth of Forth and St Andrews Bay Complex SPA red-breasted merganser population.

Changes to Prey Availability

316. Red-breasted merganser, feed primarily on a range of small fish species which occur widely throughout the SPA. Any localised impacts on prey could cause the temporary relocation of red-breasted merganser to unaffected areas, with birds predicted to return once prey abundance recovers to pre-construction levels.
317. As outlined in the section on project alone: construction and decommissioning – changes to prey availability for eider, there is potential for temporary changes in prey availability caused by impacts on the habitat arising from construction and decommissioning activities. However, in intertidal and nearshore subtidal zone the impacts will be limited as the export cables will be buried without trenching out to at least 488 m from the MHWS. Consequently, there will be no habitat loss or impacts on the availability of prey within this area.
318. Surveys indicate that the export cable route does not occur in an area which is recognised to be significantly important for red-breasted merganser. Therefore any impacts on prey species will only affect a localised area and birds will be able to relocate to areas of suitable habitat and prey availability within the SPA.  Any impacts will be temporary and localised and not lead to an adverse effect on the Outer Firth of Forth and St Andrews Bay Complex SPA populations of red-breasted merganser.

Direct Habitat Loss

319. Construction activities within the Outer Firth of Forth and St Andrews Bay Complex SPA could cause the loss of habitat which could impact on red-breasted merganser.
320. Red-breasted merganser typically occur in relatively shallow nearshore water.  The distribution of red-throated diver within the Outer Firth of Forth and St Andrews Bay Complex SPA is predominantly in coastal waters with highest densities or numbers occurring in the Tay Estuary and inner Firth of Forth (SNH and JNCC 2016).
321. The potential loss of 0.09% of the SPA due to cable protection and the potential temporary habitat loss caused by trenching and burying the cables will impact on a small proportion of the SPA red-breasted merganser population which will be able to relocate to other suitable areas until the habitat and associated prey, return to pre-construction levels. The impact will not lead to an adverse effect on the Outer Firth of Forth and St Andrews Bay Complex SPA populations of red-breasted merganser.

Project Alone: Operation and Maintenance

Disturbance and Displacement

322. Direct disturbance and displacement to red-breasted merganser during the operation and maintenance phase may arise within the Proposed Development export cable corridor (and its immediate vicinity) as a result of increased vessel movements and helicopter activity.
323. The disturbance and displacement impacts arising from operational and maintenance vessel activity will be similar to, or less than, that arising during the construction and decommissioning phases.  Consequently, it is considered that there is no potential for operational or maintenance related disturbance or displacement to lead to an adverse effect on the Outer Firth of Forth and St Andrews Bay Complex SPA red-breasted merganser population.

Changes to Prey Availability

324. As outlined in the section on project alone: operation and maintenance – changes to prey availability for eider, there will be no increase in the potential for temporary changes in prey availability caused by impacts during operating and maintenance phases. Consequently, it is considered that there is no potential for operational or maintenance related changes in prey availability to lead to an adverse effect on the Outer Firth of Forth and St Andrews Bay Complex SPA red-breasted merganser population.

Direct Habitat Loss

325. There will be no increase in direct habitat loss over and above that arising during the construction phase unless un-planned additional cable protection is required over and above the 15% of export cable that is already recognised as might requiring protection.  If additional protection is required then it is predicted to be a relatively small increase in habitat loss.  This will not be required where the cables will be buried without trenching.  Consequently, there will be minimal, if any, additional impact on red-breasted merganser through the loss of habitat during the operation and maintenance phase.
326. On this basis it is concluded that the loss of habitat during operation and maintenance phase will not lead to an adverse effect on the Outer Firth of Forth and St Andrews Bay Complex SPA populations of Red-breasted merganser.

Project Alone: Conclusion

327. The potential effects from the Proposed Development alone on the Outer Firth and Forth and St Andrews Bay Complex SPA red-breasted merganser population are predicted to be small and temporary, impacting on a small proportion of the site population.  Given this, it is concluded that the effects from the Proposed Development alone would not result in an adverse effect on this population.

Effects In-Combination: Construction, Operation, Maintenance and Decommissioning

Disturbance and Displacement

328. During construction, operation and decommissioning phases there is potential for existing marine traffic activity, including fishing and commercial vessels to cause disturbance and displacement impacts on red-breasted merganser and therefore capable of causing an in-combination impact.  Marine traffic occurs widely throughout the region, including within the SPA (see Offshore EIA report volume 3, chapter 13) and the additional vessel activity arising during construction, operation and decommissioning will not make any material difference to the level of disturbance and displacement currently present within the SPA. It is predicted that the potential increase in disturbance and displacement will not be detectable against current levels and therefore will not cause an in-combination impact that would lead to an adverse effect on Outer Firth of Forth and St Andrews Bay Complex SPA red-breasted merganser population.

Changes to Prey Availability

329. There is limited potential for in-combination impacts to affect prey availability within the Outer Firth and Forth and St Andrews Bay Complex SPA. Any impacts will be temporary with recovery following completion of the construction, operation and decommissioning activities.  There is limited, if any, potential for in-combination impacts that will cause a measurable effect on the prey of red-breasted merganser and no in-combination impacts that would limit their ability to relocate temporarily to other locations within the SPA where red-breasted merganser are known to occur. Consequently, there will be no in-combination impacts relating to changes in prey availability that would cause an adverse effect on the Outer Firth of Forth and St Andrews Bay Complex SPA red-breasted merganser population.

Direct Habitat Loss

330. Existing and planned offshore wind farms: Inch Cape, Neart na Gaoithe, Seagreen 1 and Seagreen 1A could all have potential to cause in-combination impacts within the SPA (See Offshore EIA Report, volume 2, chapter 8).  During construction and decommissioning these impacts will be temporary and in-combination impacts would only occur if activities were undertaken within the SPA simultaneously or overlapping the recovery period.  It is predicted that all construction activities for other offshore wind farms that could cause an in-combination impact will be completed prior to the commencement of construction for the proposed Development.  There will be in-combination impacts during the operation and maintenance phases of the projects.
331. Potential impacts on habitat from the Project Alone has been identified as being temporary during construction and decommissioning and there is little potential for in-combination impacts to arise with other offshore wind farms due to their construction having been completed before construction commences at the Proposed Development and similarly decommissioning may have been completed by the other projects prior to the start of decommissioning by the proposed Development.  There is potential long-term habitat loss throughout the period of operation and maintenance when a potential loss of 0.09% of the SPA could be impacted due to cable protection.  The potential long-term loss of habitat associated with the other projects is unknown.  However, the long-term loss of habitat from cable protection does not equate to loss of habitat to red-breasted merganser as they do not occur in the area where the majority of impacts on habitat from cable protection are predicted to occur. Furthermore the nearshore trenchless cabling will not impact on the habitats and it is the nearshore areas where red-breasted merganser are known to most frequently occur.
332. The potential impacts on red-breasted merganser will likely be undetectable and will not cause an in-combination impact that would lead to an adverse effect on Outer Firth of Forth and St Andrews Bay Complex SPA red-breasted merganser population.

In-combination: Conclusion

333. The potential effects from the Proposed Development in-combination with other plans or programmes on the Outer Firth and Forth and St Andrews Bay Complex SPA red-breasted merganser population are predicted to be small and temporary, impacting on a small proportion of the site population.  Given this, it is concluded that the effects from the Proposed Development in-combination would not result in an adverse effect on this population.

Assessment for the Red-throated Diver Population

334. Red-throated diver is a scarce breeding bird in the UK, with an estimated 1,255 breeding pairs, all of which breeding in northern and north-west Scotland (Woodward et al. 2020, Forrester et al. 2007).  The Scottish wintering population is estimated to be 2,270 individuals (Forrester et al. 2007).  They are widely distributed in waters around Scotland with the highest wintering population occurring along the east coast, including the Firth of Firth.
335. The site reference population of 850 individuals has been calculated based on a multi-year programme of aerial, boat-based and land-based surveys (Lawson et al. 2015).  WeBS data indicates that the peak mean population size has remained relatively stable since 2001, although there may have been a slight decrease over the years (Figure 5.7).

Figure 57: Red-throated diver population trend at the Outer Firth of Forth and St Andrews Bay Complex SPA for the period 2001 - 2020. The orange line shows the site reference population size for the SPA (2001/02 -2004/05 peak mean of 850 individuals). Data are from the Wetland Bird Survey Database (BTO 2022).

336. Site specific advice for red-throated diver is to:

• Maintain the population of non-breeding red-throated divers at a stable or increasing trend relative to the site reference population.

Potential Impacts on the Red-throated Diver Population

337. Potential impacts on the Outer Firth of Forth and St Andrews Bay Complex SPA red-throated diver population screened in for assessment are outlined in section 3.1 and in the HRA Stage One Screening Report (SSE Renewables, 2021).
338. Potential impacts from the Proposed Development could arise during construction, operation and maintenance and decommissioning and could cause direct habitat loss, changes in prey availability and disturbance and displacement.  Consequently, the focus of the assessment for this SPA population is concerned with all the Conservation Objectives.
339. Red-throated diver were occasionally recorded within the Proposed Development array area in late spring and early winter, with peak density of 0.05 birds/km2 (95%CI 0.02 – 0.09) occurring in November 2020 and equating to an estimated 200 birds (95%CI 72 – 375).  Spring peaks in abundance can be attributed to the presence of pre-breeding congregations of the species, which have previously been observed off the east coast of Scotland in late May. Birds occurring during passage could originate from any of the wintering areas located in the North Sea.
340. During intertidal and nearshore surveys red-throated divers were recorded frequently throughout the Survey Area during the autumn passage and early winter months.  Although numbers were low, with an overall peak count of just nine individuals (December 2020), this species does not typically occur in large aggregations during the non-breeding season.  Birds were generally recorded between 0-1 km from the shore.

Project Alone: Construction and Decommissioning

Disturbance and Displacement

341. Direct disturbance and displacement to red-throated diver during the construction phase may arise within the Proposed Development export cable corridor (and its immediate vicinity) as a result of increased vessel movements, as well as from other activities directly associated with the installation of the export cable.
342. Red-throated diver are recognised to be sensitive to disturbance from vessels (Goodship and Furness 2022).  Reviews of the sensitivity of different seabird species to disturbance from vessels and helicopter traffic have assessed red-throated diver as having a relatively very high sensitivity from disturbance arising from vessels (Furness et al. 2013, Fliessbach et al. 2019).
343. The Proposed Development offshore export cable encompasses 168km2 and the total area of Outer Firth of Forth and St Andrews Complex SPA is 2,720.68 km2. Consequently, no more than 6.2% of the SPA will be affected by disturbance over the whole construction phase.  Construction activities will not occur simultaneously across the entirety of the Proposed Development export cable corridor but will be undertaken within discrete areas along the cable route corridor.
344. Studies undertaken indicate that red-throated diver may be displaced by vessel traffic with studies reporting red-throated diver being flushed by approaching vessels at distances from between 250 m and 1,750 m and for flocks a median distance of 600 m (Fliessbach et al. 2019).  Similar studies have reported up to 5% of individual red-throated divers and 15% of flocks were disturbed by vessels from between 800 and 1,000 m away, the majority of remained to within 600 m of a moving vessel.  Up to 67% of all individual red-throated divers were not disturbed (i.e. fly away) until the vessel was within 200 m of them.  The study also indicated that flocks of red-throated divers were more sensitive than individuals (Norman and Ellis 2005).
345. Consequently, the area of impact from a single vessel at any one time could vary from between 0.19 km2 to 9.62 km2 (based on the minimum and maximum reported disturbance distances), equivalent to between <0.04% of the SPA and 0.35% of the SPA. During construction there is potential for up to 12 vessels to occur in the area.  On this basis a theoretical maximum area of disturbance of up to 115.4 km2 could occur, equivalent to 4.24% of the SPA.  However, during construction vessel activity will be clustered around the area of cable laying and therefore the areas of potential disturbance from each vessel will overlap and the overall area of disturbance will be considerably smaller.
346. Not all red-throated divers fly in response to vessel disturbance with 67% either swimming or diving in response to a slow moving vessel (Jarrett et al. 2018, Norman and Ellis 2005).  Red-throated diver that are displaced could return to the area following the departure of the vessel.  Studies indicate that red-throated divers are largely absent in areas where there is regular vessel traffic, e.g. shipping lanes.  However, where there is occasional or temporary disturbances at least one study reported no significant changes in abundance within 30 minutes of the vessels departure (Jarrett et al. 2018).
347. Consequently, it is predicted that any disturbance or displacement impacts arising from the construction activities within the SPA could occur over a relatively wide area but will be temporary, with red-throated diver abundance returning to pre-construction levels once the temporary disturbance caused by the vessels stops.
348. The potential for disturbance effects during decommissioning is assumed to be the same (or less) as for construction, noting that the duration of the decommissioning phase will not exceed that of construction, and may be shorter.
349. The maximum count of nine red-throated diver in nearshore and intertidal surveys is 7.9% of the SPA population (based on latest 5 year peak mean).  These will be disturbed and displaced by the presence of vessel activity within the SPA.  However, evidence shows that displacement is temporary and that birds that are displaced will be able to relocate to other locations within the SPA and return shortly after vessel activities cease.  On this basis it is considered that there is no potential for construction or decommissioning related disturbance or displacement to lead to an adverse effect on the Outer Firth of Forth and St Andrews Bay Complex SPA red-throated diver population.

Changes to Prey Availability

350. Red-throated divers appear capable of utilising a range of marine habitats and prey. They are generalist opportunistic feeders favouring pelagic schooling fish (Dierschke et al. 2017, Kleinschmidt et al. 2019). Red-throated divers wintering in the North Sea and Baltic Sea are thought to feed predominantly on small fish such as herring (Clupea harengus), sprats (Sprattus sprattus) and sandeels (Ammodytes marinus). However, they are believed to switch to alternative small prey, depending on the species of fish (Dierschke et al. 2017).
351. As outlined in the section on project alone: construction and decommissioning – changes to prey availability for eider, there is potential for temporary changes in prey availability caused by impacts on the habitat arising from construction and decommissioning activities. However, in intertidal and nearshore subtidal zone the impacts will be limited as the export cables will be buried without trenching out to at least 488 m from the MHWS. Consequently, there will be no habitat loss or impacts on the availability of prey within this area.
352. Red-throated divers appear capable of utilising a range of marine habitats and prey. They are generalist opportunistic feeders favouring pelagic schooling fish (Dierschke et al. 2017, Kleinschmidt et al. 2019).  Red-throated divers wintering in the North Sea and Baltic Sea are thought to feed predominantly on small fish such as herring (Clupea harengus), sprats (Sprattus sprattus) and sandeels (Ammodytes marinus). However, they are believed to switch to alternative small prey, depending on the species of fish (Dierschke et al. 2017).
353. Surveys indicate that the export cable route does not occur in an area which is recognised to be significantly important for red-throated diver. Therefore any impacts on prey species will only affect a localised area and birds will be able to relocate to areas of suitable habitat and prey availability within the SPA.  Any impacts will be temporary and localised and not lead to an adverse effect on the Outer Firth of Forth and St Andrews Bay Complex SPA populations of red-throated diver.

Direct Habitat Loss

354. Construction activities within the Outer Firth of Forth and St Andrews Bay Complex SPA could cause the loss of habitat which could impact on red-throated diver.
355. Red-throated diver typically feed in water depths of less than 10 m and therefore their distribution is limited to relatively shallow nearshore water (NatureScot and JNCC 2022).  Reviews of the sensitivity of different seabird species to habitat use flexibility assigned red-throated diver as ‘4’ on a five-scale ranking system. (Furness et al. 2013). Suggesting that red-throated diver are moderately to highly sensitive to the loss of habitat.  However, it is also recognised that they are capable of using a range of marine habitats (Dierschke et al. 2017).
356. The distribution of red-throated diver within the Outer Firth of Forth and St Andrews Bay Complex SPA is predominantly in coastal waters with high concentrations recorded by St Andrews Bay and the Firth of Tay area. Relatively low densities occur in waters along the export cable corridor (SNH 2015, SNH and JNCC 2016).
357. The potential loss of 0.09% of the SPA due to cable protection and the potential temporary habitat loss caused by trenching and burying the cables will impact on a small proportion of the SPA red-throated diver population which will be able to relocate to other suitable areas until the habitat and associated prey, return to pre-construction levels. The impact will not lead to an adverse effect on the Outer Firth of Forth and St Andrews Bay Complex SPA populations of red-throated diver.

Project Alone: Operation and Maintenance

Disturbance and Displacement

358. Direct disturbance and displacement to red-throated diver during the operation and maintenance phase may arise within the Proposed Development export cable corridor (and its immediate vicinity) as a result of increased vessel movements and helicopter activity.
359. The disturbance and displacement impacts arising from operational and maintenance vessel activity will be similar to, or less than, that arising during the construction and decommissioning phases.  Consequently, it is considered that there is no potential for operational or maintenance related disturbance or displacement to lead to an adverse effect on the Outer Firth of Forth and St Andrews Bay Complex SPA red-throated diver population.

Changes to Prey Availability

360. As outlined in the section on project alone: operation and maintenance – changes to prey availability for eider, there will be no increase in the potential for temporary changes in prey availability caused by impacts during operating and maintenance phases. Consequently, it is considered that there is no potential for operational or maintenance related changes in prey availability to lead to an adverse effect on the Outer Firth of Forth and St Andrews Bay Complex SPA red-throated diver population.

Direct Habitat Loss

361. There will be no increase in direct habitat loss over and above that arising during the construction phase unless un-planned additional cable protection is required over and above the 15% of export cable that is already recognised as might requiring protection.  If additional protection is required then it is predicted to be a relatively small increase in habitat loss.  This will not be required where the cables will be buried without trenching.  Consequently, there will be minimal, if any, additional impact on red-throated diver through the loss of habitat during the operation and maintenance phase.
362. On this basis it is concluded that the loss of habitat during operation and maintenance phase will not lead to an adverse effect on the Outer Firth of Forth and St Andrews Bay Complex SPA populations of Red-throated diver.

Project Alone: Conclusion

363. The potential effects from the Proposed Development alone on the Outer Firth and Forth and St Andrews Bay Complex SPA red-throated diver population are predicted to be small and temporary, impacting on a small proportion of the site population.  Given this, it is concluded that the effects from the Proposed Development alone would not result in an adverse effect on this population.

Effects In-Combination: Construction, Operation, Maintenance and Decommissioning

Disturbance and Displacement

364. During construction, operation and decommissioning phases there is potential for existing marine traffic activity, including fishing and commercial vessels to cause disturbance and displacement impacts on red-throated diver and therefore capable of causing an in-combination impact.  Marine traffic occurs widely throughout the region, including within the SPA (see Offshore EIA report volume 2, chapter 8) and the additional vessel activity arising during construction, operation and decommissioning will not make any material difference to the level of disturbance and displacement currently present within the SPA. It is predicted that the potential increase in disturbance and displacement will not be detectable against current levels and therefore will not cause an in-combination impact that would lead to an adverse effect on Outer Firth of Forth and St Andrews Bay Complex SPA red-throated diver population.

Changes to Prey Availability

27. There is limited potential for in-combination impacts to affect prey availability within the Outer Firth and Forth and St Andrews Bay Complex SPA. Any impacts will be temporary with recovery following completion of the construction, operation and decommissioning activities.  There is limited, if any, potential for in-combination impacts that will cause a measurable effect on the prey of red-throated diver and no in-combination impacts that would limit their ability to relocate temporarily to other locations within the SPA where red-throated diver are known to occur. Consequently, there will be no in-combination impacts relating to changes in prey availability that would cause an adverse effect on the Outer Firth of Forth and St Andrews Bay Complex SPA red-throated diver population.

Direct Habitat Loss

365. Existing and planned offshore wind farms: Inch Cape, Neart na Gaoithe, Seagreen 1 and Seagreen 1A could all have potential to cause in-combination impacts within the SPA (see Offshore EIA report, volume 2, chapter 8).  During construction and decommissioning these impacts will be temporary and in-combination impacts would only occur if activities were undertaken within the SPA simultaneously or overlapping the recovery period.  It is predicted that all construction activities for other offshore wind farms that could cause an in-combination impact will be completed prior to the commencement of construction for the proposed Development.  There will be in-combination impacts during the operation and maintenance phases of the projects.
366. Potential impacts on habitat from the Project Alone has been identified as being temporary during construction and decommissioning and there is little potential for in-combination impacts to arise with other offshore wind farms due to their construction having been completed before construction commences at the Proposed Development and similarly decommissioning may have been completed by the other projects prior to the start of decommissioning by the proposed Development.  There is potential long-term habitat loss throughout the period of operation and maintenance when a potential loss of 0.09% of the SPA could be impacted due to cable protection.  The potential long-term loss of habitat associated with the other projects is unknown.  However, the long-term loss of habitat from cable protection does not equate to loss of habitat to red-throated diver as they do not occur in the area where the majority of impacts on habitat from cable protection are predicted to occur. Furthermore the nearshore trenchless cabling will not impact on the habitats and it is the nearshore areas where red-throated diver are known to most frequently occur.
367. The potential impacts on red-throated diver will likely be undetectable and will not cause an in-combination impact that would lead to an adverse effect on Outer Firth of Forth and St Andrews Bay Complex SPA red-throated diver population.

In-combination: Conclusion

368. The potential effects from the Proposed Development in-combination with other plans or programmes on the Outer Firth and Forth and St Andrews Bay Complex SPA red-throated diver population are predicted to be small and temporary, impacting on a small proportion of the site population.  Given this, it is concluded that the effects from the Proposed Development in-combination would not result in an adverse effect on this population.

Assessment for the Slavonian Grebe Population

369. Slavonian grebe is a rare breeding bird in the UK, with less than 30 breeding pairs, all of which breed in Scotland (Woodward et al. 2020, Forrester et al. 2007).  The Scottish wintering population is estimated to be between 300 and 500 individuals (Forrester et al. 2007).  They are widely distributed in waters around Scotland with the highest wintering population occurring around the islands of Orkney, the Moray Firth and the Firth of Forth.
370. The site reference population of 30 individuals has been calculated based on a multi-year programme of aerial, boat-based and land-based surveys (Lawson et al. 2015).  WeBS data indicates that the peak mean population size has decreased since 2006 but has remained largely above the site reference populations.

Figure 58: Slavonian grebe population trend at the Outer Firth of Forth and St Andrews Bay Complex SPA for the period 2001 - 2020. The orange line shows the site reference population size for the SPA (2006/07 -2010/11 peak mean of 30 individuals). Data are from the Wetland Bird Survey Database (BTO 2022).

371. Site specific advice for Slavonian grebe is to:

• Maintain the population of non-breeding Slavonian grebes at a stable or increasing trend relative to the site reference population

The potential Impacts on the Slavonian grebe population

372. Potential impacts on the Outer Firth of Forth and St Andrews Bay Complex SPA Slavonian grebe population screened in for assessment are outlined in section 3.1 and in the HRA Stage One Screening Report (SSE Renewables, 2021). The assessment of potential barrier and collision impacts on Slavonian grebe in the Firth of Forth SPA are addressed in the Migratory Bird Assessment (Section 5.8).
373. Potential impacts from the Proposed Development could arise during construction, operation and maintenance and decommissioning and could cause direct habitat loss, changes in prey availability and disturbance and displacement.  Consequently, the focus of the assessment for this SPA population is concerned with all the Conservation Objectives.
374. Slavonian grebe were not recorded within the Proposed Development array area.  During intertidal and nearshore surveys one Slavonian grebe was recorded in March 2021.

Project Alone: Construction and Decommissioning

Disturbance and Displacement

375. Direct disturbance and displacement to Slavonian grebe during the construction phase may arise within the Proposed Development export cable corridor (and its immediate vicinity) as a result of increased vessel movements, as well as from other activities directly associated with the installation of the export cable.
376. Slavonian grebe are recognised to be moderately sensitive to disturbance from vessels (Goodship and Furness 2022).  Reviews of the sensitivity of different seabird species to disturbance from vessels have assessed Slavonian grebe as having medium sensitivity from disturbance arising from vessels (Furness et al. 2013, Fliessbach et al. 2019).  However, some studies have indicated that Slavonian grebe exhibit relatively high levels of behavioural and flight response to approaching vessels and therefore may be considered to be very highly sensitive to vessel disturbance (Jarrett et al. 2022).
377. The Proposed Development offshore export cable encompasses 168 km2 and the total area of Outer Firth of Forth and St Andrews Complex SPA is 2,720.68 km2. Consequently, no more than 6.2% of the SPA will be affected by disturbance over the whole construction phase.  Construction activities will not occur simultaneously across the entirety of the Proposed Development export cable corridor but will be undertaken within discrete areas along the cable route corridor.
378. Studies undertaken indicate that Slavonian grebe may be displaced by vessel traffic with studies reporting Slavonian grebe being flushed by approaching vessels at distances from between 30 m and 1,100 m and for flocks a median distance of 265 m (Fliessbach et al. 2019). 
379. Consequently, the area of impact from a single vessel at any one time could vary from between 0.003 km2 to 3.81 km2 (based on the minimum and maximum reported disturbance distances), equivalent to between <0.001% of the SPA and 0.14% of the SPA. During construction there is potential for up to 12 vessels to occur in the area.  On this basis a theoretical maximum area of disturbance of up to 45.7 km2 could occur, equivalent to 1.68% of the SPA.  However, during construction vessel activity will be clustered around the area of cable laying and therefore the areas of potential disturbance from each vessel will overlap and the overall area of disturbance will be considerably smaller.
380. Not all Slavonian grebe will take to flight in response to vessel disturbance with 59% either swimming or diving in response to a slow moving vessel (Jarrett et al. 2018).  Slavonian grebe that are displaced could return to the area following the departure of the vessel.  Studies indicate that where there is occasional or temporary disturbances there are no significant changes in abundance within 30 minutes of the vessels departure (Jarrett et al. 2018).
381. Consequently, it is predicted that any disturbance or displacement impacts arising from the construction activities within the SPA could occur over a relatively wide area but will be temporary, with Slavonian grebe abundance returning to pre-disturbance levels once the temporary disturbance caused by the vessels stops.
382. The potential for disturbance effects during decommissioning is assumed to be the same (or less) as for construction, noting that the duration of the decommissioning phase will not exceed that of construction, and may be shorter.
383. The maximum and only observation of Slavonian grebe during nearshore and intertidal surveys is of one bird, equivalent to 3.06% of the SPA population (based on latest 5 year peak mean).  Although birds present could be disturbed and displaced by the presence of vessel activity within the SPA, evidence shows that displacement is temporary and that birds that are displaced will be able to relocate to other locations within the SPA and return shortly after vessel activities cease.  On this basis it is considered that there is no potential for construction or decommissioning related disturbance or displacement to lead to an adverse effect on the Outer Firth of Forth and St Andrews Bay Complex SPA Slavonian grebe population.

Changes to Prey Availability

384. Slavonian grebe feed primarily on a range of small fish species.
385. As outlined in the section on project alone: construction and decommissioning – changes to prey availability for eider, there is potential for temporary changes in prey availability caused by impacts on the habitat arising from construction and decommissioning activities. However, in intertidal and nearshore subtidal zone the impacts will be limited as the export cables will be buried without trenching out to at least 488 m from the MHWS. Consequently, there will be no habitat loss or impacts on the availability of prey within this area.
386. Any localised impacts on prey could cause the temporary relocation of Slavonian grebe to unaffected areas, with birds predicted to return once prey abundance recovers to pre-construction levels.
387. Surveys indicate that the export cable route does not occur in an area which is recognised to be significantly important for Slavonian grebe, with only one bird recorded during surveys. Therefore any impacts on prey species will only affect a localised area and birds will be able to relocate to areas of suitable habitat and prey availability within the SPA.  Any impacts will be temporary and localised and not lead to an adverse effect on the Outer Firth of Forth and St Andrews Bay Complex SPA populations of Slavonian grebe.

Direct Habitat Loss

388. Construction activities within the Outer Firth of Forth and St Andrews Bay Complex SPA could cause the loss of habitat which could impact on Slavonian grebe.
389. Slavonian grebe typically feed on small in water depths of less than 14 m and therefore their distribution is limited to relatively shallow nearshore water (NatureScot and JNCC 2022).  Reviews of the sensitivity of different seabird species to habitat use flexibility assigned Slavonian grebe as ‘4’ on a five-scale ranking system. (Furness et al. 2013). Suggesting that they are moderately to highly sensitive to the loss of habitat.
390. The distribution of Slavonian grebe within the Outer Firth of Forth and St Andrews Bay Complex SPA is predominantly in coastal waters with highest concentrations recorded in the Firth of Forth and to a lesser extent St Andrews Bay area (SNH 2015, SNH and JNCC 2016).
391. The potential loss of 0.09% of the SPA due to cable protection and the potential temporary habitat loss caused by trenching and burying the cables will impact on a small proportion of the SPA Slavonian grebe population which will be able to relocate to other suitable areas until the habitat and associated prey, return to pre-construction levels. The impact will not lead to an adverse effect on the Outer Firth of Forth and St Andrews Bay Complex SPA populations of Slavonian grebe.

Project Alone: Operation and Maintenance

Disturbance and Displacement

392. Direct disturbance and displacement to Slavonian grebe during the operation and maintenance phase may arise within the Proposed Development export cable corridor (and its immediate vicinity) as a result of increased vessel movements.
393. The disturbance and displacement impacts arising from operational and maintenance vessel activity will be similar to, or less than, that arising during the construction and decommissioning phases.  Consequently, it is considered that there is no potential for operational or maintenance related disturbance or displacement to lead to an adverse effect on the Outer Firth of Forth and St Andrews Bay Complex SPA Slavonian grebe population.

Changes to Prey Availability

394. There will be no increase in the potential for temporary changes in prey availability caused by impacts during operating and maintenance phases. Consequently, it is considered that there is no potential for operational or maintenance related changes in prey availability to lead to an adverse effect on the Outer Firth of Forth and St Andrews Bay Complex SPA Slavonian grebe population.

Direct Habitat Loss

395. There will be no increase in direct habitat loss over and above that arising during the construction phase unless un-planned additional cable protection is required over and above the 15% of export cable that is already recognised as might requiring protection.  If additional protection is required then it is predicted to be a relatively small increase in habitat loss.  This will not be required where the cables will be buried without trenching.  Consequently, there will be minimal, if any, additional impact on Slavonian grebe through the loss of habitat during the operation and maintenance phase.
396. On this basis it is concluded that the loss of habitat during operation and maintenance phase will not lead to an adverse effect on the Outer Firth of Forth and St Andrews Bay Complex SPA populations of Slavonian grebe.

Project Alone: Conclusion

397. The potential effects from the Proposed Development alone on the Outer Firth and Forth and St Andrews Bay Complex SPA Slavonian grebe population are predicted to be small and temporary, impacting on a small proportion of the site population.  Given this, it is concluded that the effects from the Proposed Development alone would not result in an adverse effect on this population.

Effects In-Combination: Construction, Operation, Maintenance and Decommissioning

Disturbance and Displacement

398. During construction, operation and decommissioning phases there is potential for existing marine traffic activity, including fishing and commercial vessels to cause disturbance and displacement impacts on Slavonian grebe and therefore capable of causing an in-combination impact.  Marine traffic occurs widely throughout the region, including within the SPA (see Offshore EIA report volume 2, chapter 13) and the additional vessel activity arising during construction, operation and decommissioning will not make any material difference to the level of disturbance and displacement currently present within the SPA. It is predicted that the potential increase in disturbance and displacement will not be detectable against current levels and therefore will not cause an in-combination impact that would lead to an adverse effect on Outer Firth of Forth and St Andrews Bay Complex SPA Slavonian grebe population.

Changes to Prey Availability

399. There is limited potential for in-combination impacts to affect prey availability within the Outer Firth and Forth and St Andrews Bay Complex SPA. Any impacts will be temporary with recovery following completion of the construction, operation and decommissioning activities.  There is limited, if any, potential for in-combination impacts that will cause a measurable effect on the prey of Slavonian grebe and no in-combination impacts that would limit their ability to relocate temporarily to other locations within the SPA where Slavonian grebe are known to occur. Consequently, there will be no in-combination impacts relating to changes in prey availability that would cause an adverse effect on the Outer Firth of Forth and St Andrews Bay Complex SPA Slavonian grebe population.

Direct Habitat Loss

400. Existing and planned offshore wind farms: Inch Cape, Neart na Gaoithe, Seagreen 1 and Seagreen 1A could all have potential to cause in-combination impacts within the SPA (see Offshore EIA report, volume 2, chapter 8).  During construction and decommissioning these impacts will be temporary and in-combination impacts would only occur if activities were undertaken within the SPA simultaneously or overlapping the recovery period.  It is predicted that all construction activities for other offshore wind farms that could cause an in-combination impact will be completed prior to the commencement of construction for the proposed Development.  There will be in-combination impacts during the operation and maintenance phases of the projects.
401. Potential impacts on habitat from the Project Alone has been identified as being temporary during construction and decommissioning and there is little potential for in-combination impacts to arise with other offshore wind farms due to their construction having been completed before construction commences at the Proposed Development and similarly decommissioning may have been completed by the other projects prior to the start of decommissioning by the proposed Development.  There is potential long-term habitat loss throughout the period of operation and maintenance when a potential loss of 0.09% of the SPA could be impacted due to cable protection.  The potential long-term loss of habitat associated with the other projects is unknown.  However, the long-term loss of habitat from cable protection does not equate to loss of habitat to Slavonian grebe as they do not occur in the area where the majority of impacts on habitat from cable protection are predicted to occur. Furthermore the nearshore trenchless cabling will not impact on the habitats and it is the nearshore areas where Slavonian grebe are known to most frequently occur.
402. The potential impacts on Slavonian grebe will likely be undetectable and will not cause an in-combination impact that would lead to an adverse effect on Outer Firth of Forth and St Andrews Bay Complex SPA Slavonian grebe population.

In-combination: Conclusion

403. The potential effects from the Proposed Development in-combination with other plans or programmes on the Outer Firth and Forth and St Andrews Bay Complex SPA Slavonian grebe population are predicted to be small and temporary, impacting on a small proportion of the site population.  Given this, it is concluded that the effects from the Proposed Development in-combination would not result in an adverse effect on this population.

Assessment for the Kittiwake Population

404. Kittiwake occur widely across the east coast of Scotland both during the breeding and non-breeding periods.  Kittiwakes using the Outer Firth of Forth and St Andrews Bay Complex SPA include those breeding at the following SPAs:

• Forth Islands SPA;
• St Abb’s Head to Fast Castle SPA;
• Fowlsheugh SPA;
• Buchan Ness to Collieston Coast SPA; and
• Troup, Pennan and Lion’s Head SPA.
  405. Consequently, these SPA populations are considered functionally linked to the Outer Firth of Forth and St Andrews Bay Complex SPA.
  406. No site-reference population is set for kittiwake at the Outer Firth of Forth and St Andrews Bay Complex SPA due to the turnover of kittiwakes within the foraging area. For breeding kittiwake, when assessing plans or projects, the population impact should be considered in relation to the site reference populations for the above SPAs (NatureScot and JNCC 2022).
  407. Species specific advice in relation to kittiwake is to:
• Ensure breeding kittiwake have the ability to recover at the relevant SPA breeding colonies.
• Ensure kittiwake within Outer Firth of Forth and St Andrews Bay Complex SPA are not at significant risk from injury or mortality during the breeding and non-breeding seasons.
• Ensure kittiwake can move safely between the site and important areas of functionally linked land outwith the site.

The Potential Impacts on the Kittiwake Population

408. Potential impacts from the Proposed Development could arise during construction, operation and maintenance and decommissioning and could cause direct habitat loss, changes in prey availability and disturbance and displacement and collision impacts.  Consequently, the focus of the assessment for this SPA population is concerned with all the Conservation Objectives.
409. The potential impacts on kittiwake for each of the SPAs that are functionally linked to the Outer Firth of Forth and St Andrews Bay Complex SPA have been assessed under each relevant SPA.  The conclusions for each assessment for the Proposed Development alone are presented in Table 5.4   Open ▸ and apply to breeding and non-breeding populations during construction, operation and decommissioning phases.
410. The conclusions for each assessment for the Proposed Development in-combination with other plans or programmes are presented in Table 5.5   Open ▸ and apply to breeding and non-breeding populations during construction, operation and decommissioning phases.

Table 5.4:  Potential for adverse effects on kittiwake from SPAs functionally linked to the Outer Firth of Forth and St Andrews Bay Complex SPA.

Table 5.5:  Potential for in-combination adverse effects on kittiwake from SPAs functionally linked to the Outer Firth of Forth and St Andrews Bay Complex SPA. * Adverse effected concluded under the Scoping Approach only.

411. The following conclusions are supported by the assessments presented in sections 5.7.1 to 5.7.3 inclusive, and sections 5.7.5 to 5.7.6 inclusive.
412. For the Forth Islands SPA, whilst it is concluded that the effects from the Proposed Development alone would not result in an adverse effect on the kittiwake population, it is concluded that there is the potential for an adverse effect as a result of the predicted effects from (i) the Proposed Development in-combination with the other Forth and Tay wind farms and (ii) the Proposed Development in-combination with the other UK North Sea wind farms. This conclusion applies to the assessments undertaken according to both the Developer Approach and the Scoping Approach.
413. For the St. Abb’s Head to Fast Castle SPA kittiwake population, the potential effects from the Proposed Development alone and in-combination with either the other Forth and Tay wind farms or the other UK North Sea wind farms due to mortality from displacement, barrier effects and collisions during the operation and maintenance phase are predicted to have the potential to result in marked reductions in population size relative to the size in the absence of these effects. Therefore, there is considered to be the potential for an adverse effect on the St Abb’s Head to Fast Castle SPA kittiwake population as a result of the Proposed Development alone and in-combination according to both the Developer and Scoping Approaches.
414. It is considered that the predicted levels of impact from the Proposed Development alone on the Fowlsheugh SPA kittiwake population are of a small (for the Developer Approach) to, at most, moderate scale (for the upper range of the Scoping Approach). Thus, the effects from the Proposed Development alone would not result in an adverse effect on this SPA population, but it is concluded that there is the potential for an adverse effect on the Fowlsheugh kittiwake population as a result of the predicted effects from (i) the Proposed Development in-combination with the other Forth and Tay wind farms and (ii) the Proposed Development in-combination with the other UK North Sea wind farms. This conclusion applies to the assessments undertaken according to both the Developer and Scoping Approaches.
415. Similarly for the Buchan Ness to Collieston Coast SPA kittiwake population, it is concluded that the effects from the Proposed Development alone would not result in an adverse effect on this population, but it is concluded that there is the potential for an adverse effect as a result of the Proposed Development in-combination with the other UK North Sea wind farms, as determined by the Scoping Approach. However, when based upon the Developer Approach, it is concluded that there is no potential for an adverse effect on the SPA population as a result of the predicted effects from the Proposed Development in-combination with the other UK North Sea wind farms. It is considered that the level of effects on kittiwakes assumed by the Scoping Approach are overly precautionary and without any reasonable basis or support from the available evidence. Given this, it is considered that greater weight should be given to the conclusions as determined by the Developer Approach.
416. For Troup, Pennan and Lion’s Heads SPA, the predicted levels of impact for the Proposed Development in-combination with the other UK North Sea wind farms are inevitably greater for the Scoping Approach than as determined by the Developer Approach. It is considered that these may, potentially, be sufficient to result in an adverse effect on this SPA population. However, it is considered that the level of effects on kittiwakes assumed by the Scoping Approach are overly precautionary and without any reasonable basis or support from the available evidence. Given this, it is considered that greater weight should be given to the conclusions as determined by the Developer Approach.
417. On the basis that the potential for adverse effects arising have been identified on Forth Islands SPA, St Abb’s Head to Fast Castle SPA, Fowlsheugh SPA, Buchan Ness to Collieston Coast SPA and Troup Head, Pennan and Lion’s Heads SPA, kittiwake populations and these colonies are functionally linked to the Outer Firth of Forth and St Andrews Bay Complex SPA it is concluded that there is potential for an adverse effect on kittiwake at the Outer Firth of Forth and St Andrews Bay Complex SPA from the Proposed Development alone and in-combination.

Assessment for the Black-headed Gull Population

418. Black-headed gulls are distributed throughout Scotland, primarily on the east and south-west coasts (Forrester et al., 2007). As well as birds arriving from elsewhere in the UK, many black-headed gulls migrate from northern and eastern Europe. Relatively large flocks of wintering birds have been observed within the Firth of Forth, such as at Skinflats and the Isle of May, located to the west of the survey area (Forrester et al., 2007).
419. The citation population of 26,835 individuals is based on winter gull surveys undertaken between 2003/04 and 2005/06 (NatureScot 2020) and based on the WeBS counts data the population has remained relatively stable since the last survey was undertaken (BTO 2022).

Figure 59: Black-headed gull population trend at the Outer Firth of Forth and St Andrews Bay Complex SPA for the period 2001 - 2020. The orange line shows the population at the time of site designation peak mean of 26,835 individuals). Data are from the Wetland Bird Survey Database (BTO 2022)

420. Species specific advice for black-headed gull is to:

• Ensure black-headed gulls within Outer Firth of Forth and St Andrews Bay Complex SPA are not at significant risk from injury or mortality during the non-breeding season.
• Ensure black-headed gulls can move safely between the site and important areas of functionally linked land outwith the site.

The Potential for Impacts on the Black-headed Gull Population

421. Potential impacts from the Proposed Development could arise during construction, operation and maintenance and decommissioning and could cause direct habitat loss, changes in prey availability and disturbance and displacement and collision impacts.  Consequently, the focus of the assessment for this SPA population is concerned with all the Conservation Objectives.
422. Black-headed gulls were uncommon in Offshore Ornithology Study Area and were only recorded during the non-breeding season with a mean seasonal peak population estimated at nine birds (95%CI 1 – 24) and a density of <0.001 birds/km2.  During inter-tidal and nearshore surveys black-headed gulls were regularly present throughout the year with a peak count of 265 during October.  Birds were mostly recorded out to 1 km from the shore, although were mainly recorded in the shallow nearshore waters between 0-500 m.

Project Alone: Construction and Decommissioning

Disturbance and Displacement

423. Direct disturbance and displacement to black-headed gull during the construction phase may arise within the Proposed Development export cable corridor (and its immediate vicinity) as a result of increased vessel movements, as well as from other activities directly associated with the installation of the export cable.
424. Reviews of the sensitivity of different seabird species to disturbance from vessels and helicopter traffic have assessed Black-headed gull as having relatively low sensitivity from disturbance arising from vessels (Furness et al. 2013).  Consequently, it is predicted that any disturbance or displacement impacts arising from the construction activities within the SPA would be localised and, should it occur, be temporary.
425. The potential for disturbance effects during decommissioning is assumed to be the same (or less) as for construction, noting that the duration of the decommissioning phase will not exceed that of construction, and may be shorter.
426. The maximum count of 265 black-headed gulls recorded during nearshore and intertidal surveys is equivalent to 5.2% of the SPA population (based on latest 5 year peak mean) and 0.99% of the citation population.  Although birds present could be disturbed and displaced by the presence of vessel activity within the SPA, evidence shows that displacement is temporary and that birds that are displaced will be able to relocate to other locations within the SPA and return shortly after vessel activities cease.  On this basis it is considered that there is no potential for construction or decommissioning related disturbance or displacement to lead to an adverse effect on the Outer Firth of Forth and St Andrews Bay Complex SPA black-headed gull population.

Changes to Prey Availability

427. Black-headed gulls are opportunistic feeders and any changes in prey availability will be relatively localised and temporary.  Black-headed gull occur widely across the SPA and therefore not restricted by prey availability and will be able to forage elsewhere if needed to. On this basis it is considered that there is no potential for construction or decommissioning related changes in prey availability to lead to an adverse effect on the Outer Firth of Forth and St Andrews Bay Complex SPA black-headed gull population.

Direct Habitat Loss

428. Construction activities within the Outer Firth of Forth and St Andrews Bay Complex SPA could cause the loss of habitat which could impact on black-headed gull.
429. Black-headed gull feed on the sea surface and there will be no direct impact from the loss of habitat to black-headed gull. On this basis it is considered that there is no potential for construction or decommissioning related habitat loss to lead to an adverse effect on the Outer Firth of Forth and St Andrews Bay Complex SPA black-headed gull population.

Project Alone: Operation

Disturbance and Displacement

430. On-going routine maintenance could cause disturbance and displacement to black-headed gull during the operation phase within the Proposed Development export cable corridor (and its immediate vicinity) as a result of increased vessel movements and helicopter activity, as well as from other activities directly associated with the maintenance of the export cable.
431. Black-headed gull are recognised to have low sensitivity to disturbance and displacement and therefore any impacts will be temporary and birds will be able to relocate to undisturbed areas. On this basis it is considered that there is no potential for operational related disturbance or displacement to lead to an adverse effect on the Outer Firth of Forth and St Andrews Bay Complex SPA black-headed gull population.

Project Alone: Conclusion

432. The potential effects from the Proposed Development alone on the Outer Firth and Forth and St Andrews Bay Complex SPA black-headed gull population are predicted to be small and temporary, impacting on a small proportion of the site population.  Given this, it is concluded that the effects from the Proposed Development alone would not result in an adverse effect on this population.

Effects In-Combination: Construction, Operation, Maintenance and Decommissioning

Disturbance and Displacement

433. During construction, operation and decommissioning phases there is potential for existing marine traffic activity, including fishing and commercial vessels to cause disturbance and displacement impacts on black-headed gull and therefore capable of causing an in-combination impact.  Marine traffic occurs widely throughout the region, including within the SPA (see Offshore EIA report volume 2, chapter 13) and the additional vessel activity arising during construction, operation and decommissioning will not make any material difference to the level of disturbance and displacement currently present within the SPA. It is predicted that the potential increase in disturbance and displacement will not be detectable against current levels and therefore will not cause an in-combination impact that would lead to an adverse effect on Outer Firth of Forth and St Andrews Bay Complex SPA black-headed gull population.

Changes to Prey Availability

434. There is limited potential for in-combination impacts to affect prey availability within the Outer Firth and Forth and St Andrews Bay Complex SPA. Any impacts will be temporary with recovery following completion of the construction, operation and decommissioning activities.  There is limited, if any, potential for in-combination impacts that will cause a measurable effect on the prey of black-headed gull and no in-combination impacts that would limit their ability to relocate temporarily to other locations within the SPA where black-headed gull are known to occur. Consequently, there will be no in-combination impacts relating to changes in prey availability that would cause an adverse effect on the Outer Firth of Forth and St Andrews Bay Complex SPA black-headed gull population.

Direct Habitat Loss

435. Existing and planned offshore wind farms: Inch Cape, Neart na Gaoithe, Seagreen 1 and Seagreen 1A could all have potential to cause in-combination impacts within the SPA (see Offshore EIA report volume 2, chapter 8).  During construction and decommissioning these impacts will be temporary and in-combination impacts would only occur if activities were undertaken within the SPA simultaneously or overlapping the recovery period.  It is predicted that all construction activities for other offshore wind farms that could cause an in-combination impact will be completed prior to the commencement of construction for the proposed Development.  There will be in-combination impacts during the operation and maintenance phases of the projects.
436. Potential impacts on habitat from the Project Alone has been identified as being temporary during construction and decommissioning and there is little potential for in-combination impacts to arise with other offshore wind farms due to their construction having been completed before construction commences at the Proposed Development and similarly decommissioning may have been completed by the other projects prior to the start of decommissioning by the proposed Development.  There is potential long-term habitat loss throughout the period of operation and maintenance when a potential loss of 0.09% of the SPA could be impacted due to cable protection.  The potential long-term loss of habitat associated with the other projects is unknown.  However, the long-term loss of habitat from cable protection does not equate to loss of habitat to black-headed gull as they do not occur in the area where the majority of impacts on habitat from cable protection are predicted to occur. Furthermore the nearshore trenchless cabling will not impact on the habitats and it is the nearshore areas where black-headed gull are known to most frequently occur.
437. The potential impacts on black-headed gull will likely be undetectable and will not cause an in-combination impact that would lead to an adverse effect on Outer Firth of Forth and St Andrews Bay Complex SPA black-headed gull population.

In-combination: Conclusion

438. The potential effects from the Proposed Development in-combination with other plans or programmes on the Outer Firth and Forth and St Andrews Bay Complex SPA black-headed gull population are predicted to be small and temporary, impacting on a small proportion of the site population.  Given this, it is concluded that the effects from the Proposed Development in-combination would not result in an adverse effect on this population.

Assessment for the Little Gull Population

439. Little gull migrate to UK coastal environments for the non-breeding period. Post-breeding adult birds usually arrive in Scotland from Europe between late July and August, followed by juvenile birds, observed in the highest concentrations along the Angus and Dundee coast (Forrester et al., 2007). A secondary influx generally occurs between October and November, mainly consisting of adult and first-winter birds (Forrester et al., 2007).
440. The citation population of 126 individuals is based on winter gull surveys undertaken between 2001/02 and 2004/05 (NatureScot 2020) and based on WeBS counts data the population has fluctuated since 2001 (BTO 2022) (Figure 5.10).

Figure 510: Little gull population trend at the Outer Firth of Forth and St Andrews Bay Complex SPA for the period 2001 - 2020. The orange line shows the site reference population size for the SPA (2001/02 -2004/05 peak mean of 126 individuals). Data are from the Wetland Bird Survey Database (BTO 2022)

441. Species specific advice for little gull is to:

• Maintain the extent and distribution of the supporting habitats for little gulls within the site.
• Maintain the condition of supporting habitats and associated processes.
• Existing water quality should be maintained and any increase in nutrients, turbidity or contaminants where this could reduce supporting habitats should be avoided

Project Alone: Construction and Decommissioning

Disturbance and Displacement

442. Direct disturbance and displacement to little gull during the construction phase may arise within the Proposed Development export cable corridor (and its immediate vicinity) as a result of increased vessel movements, as well as from other activities directly associated with the installation of the export cable.
443. Reviews of the sensitivity of different seabird species to disturbance from vessels and helicopter traffic have not assessed little gull although generally Gulls are considered not to be sensitive to disturbance or displacement by the physical presence of vessels and that is predicted to be the case for little gull (Furness et al. 2013).  Consequently, it is predicted that any disturbance or displacement impacts arising from the construction activities within the SPA would be localised and, should it occur, be temporary.
444. The potential for disturbance effects during decommissioning is assumed to be the same (or less) as for construction, noting that the duration of the decommissioning phase will not exceed that of construction, and may be shorter.
445. Little gulls were regularly recorded in the Offshore Ornithology Study Area with peak population estimates occurring in August with up to 420 birds (95%CI 242 – 629) and a density of 0.11 birds/km2.  No little gulls were recorded during nearshore and intertidal surveys.  Although birds present could be disturbed and displaced by the presence of vessel activity within the SPA, displacement will be temporary and that birds that are displaced will be able to relocate to other locations within the SPA and return shortly after vessel activities cease. On this basis it is considered that there is no potential for construction or decommissioning related disturbance or displacement to lead to an adverse effect on the Outer Firth of Forth and St Andrews Bay Complex SPA black-headed gull population.

Changes to Prey Availability

446. Little gull are opportunistic feeders and any changes in prey availability will be relatively localised and temporary.  Little gull occur widely across the SPA and are therefore not restricted by prey availability and will be able to forage elsewhere if needed to. On this basis it is considered that there is no potential for construction or decommissioning related changes in prey availability to lead to an adverse effect on the Outer Firth of Forth and St Andrews Bay Complex SPA black-headed gull population.

Direct Habitat Loss

447. Construction activities within the Outer Firth of Forth and St Andrews Bay Complex SPA could cause the loss of habitat which could impact on little gull.
448. Little gull feed on the sea surface and there will be no direct impact from the loss of habitat to little gull. On this basis it is considered that there is no potential for construction or decommissioning related habitat loss to lead to an adverse effect on the Outer Firth of Forth and St Andrews Bay Complex SPA little gull population.

Project Alone: Operation

Disturbance and Displacement

449. On-going routine maintenance could cause disturbance and displacement to little gull during the operation phase within the Proposed Development export cable corridor (and its immediate vicinity) as a result of increased vessel movements and helicopter activity, as well as from other activities associated with the maintenance of the export cable.
450. Little gull are believed to have low sensitivity to disturbance and displacement and therefore any impacts will be temporary and birds will be able to relocate to undisturbed areas. On this basis it is considered that there is no potential for operational related disturbance or displacement to lead to an adverse effect on the Outer Firth of Forth and St Andrews Bay Complex SPA little gull population.

Collision Impacts

451. The Proposed Development array area lies outwith the Outer Firth of Forth and St Andrews Bay Complex SPA.  However, little gulls originating from the SPA could occur within the Proposed Development array area and be impacted by collision. 
452. Collision risk modelling estimate between two and four little gull collisions during the non-breeding period, based on either the Developers Approach or the Scoping Approach (Offshore EIA, volume 3, appendix 11.3).  No collisions are predicted to occur during the breeding period (Offshore EIA, volume 3, appendix 11.3).
453. The Outer Firth of Forth and St Andrews Bay Complex SPA citation population is 126 individuals and the regional baseline population is 3,000 adults.  Therefore, the SPA holds 4.2% of the regional little gull population. On this basis approximately 4.2% of the little gull collisions could be birds from the SPA.  Consequently between 0.08 and 0.17 little gull collisions per year could be from birds associated with the SPA. It is therefore predicted that the annual collision mortality will be very low and that there is no potential for operational related collision impacts to lead to an adverse effect on the Outer Firth of Forth and St Andrews Bay Complex SPA little gull population.

Project Alone: Conclusion

454. The potential effects from the Proposed Development alone on the Outer Firth and Forth and St Andrews Bay Complex SPA little gull population are predicted to be small and temporary, impacting on a small proportion of the site population.  Given this, it is concluded that the effects from the Proposed Development alone would not result in an adverse effect on this population.

Effects In-Combination: Construction, Operation, Maintenance and Decommissioning

Disturbance and Displacement

28. During construction, operation and decommissioning phases there is potential for existing marine traffic activity, including fishing and commercial vessels to cause disturbance and displacement impacts on little gull and therefore capable of causing an in-combination impact.  Marine traffic occurs widely throughout the region, including within the SPA (see Offshore EIA report volume 2, chapter 13) and the additional vessel activity arising during construction, operation and decommissioning will not make any material difference to the level of disturbance and displacement currently present within the SPA. It is predicted that the potential increase in disturbance and displacement will not be detectable against current levels and therefore will not cause an in-combination impact that would lead to an adverse effect on Outer Firth of Forth and St Andrews Bay Complex SPA little gull population.

Changes to Prey Availability

455. There is limited potential for in-combination impacts to affect prey availability within the Outer Firth and Forth and St Andrews Bay Complex SPA. Any impacts will be temporary with recovery following completion of the construction, operation and decommissioning activities.  There is limited, if any, potential for in-combination impacts that will cause a measurable effect on the prey of little gull and no in-combination impacts that would limit their ability to relocate temporarily to other locations within the SPA where little gull are known to occur. Consequently, there will be no in-combination impacts relating to changes in prey availability that would cause an adverse effect on the Outer Firth of Forth and St Andrews Bay Complex SPA little gull population.

Direct Habitat Loss

456. Existing and planned offshore wind farms: Inch Cape, Neart na Gaoithe, Seagreen 1 and Seagreen 1A could all have potential to cause in-combination impacts within the SPA (see Offshore EIA report volume 2, chapter 8). During construction and decommissioning these impacts will be temporary and in-combination impacts would only occur if activities were undertaken within the SPA simultaneously or overlapping the recovery period.  It is predicted that all construction activities for other offshore wind farms that could cause an in-combination impact will be completed prior to the commencement of construction for the proposed Development.  There will be in-combination impacts during the operation and maintenance phases of the projects.
457. Potential impacts on habitat from the Project Alone has been identified as being temporary during construction and decommissioning and there is little potential for in-combination impacts to arise with other offshore wind farms due to their construction having been completed before construction commences at the Proposed Development and similarly decommissioning may have been completed by the other projects prior to the start of decommissioning by the proposed Development.  There is potential long-term habitat loss throughout the period of operation and maintenance when a potential loss of 0.09% of the SPA could be impacted due to cable protection.  The potential long-term loss of habitat associated with the other projects is unknown. 
458. The potential impacts on little gull will likely be undetectable and will not cause an in-combination impact that would lead to an adverse effect on Outer Firth of Forth and St Andrews Bay Complex SPA little gull population.

Collision Impacts

459. There is potential for an in-combination collision impacts on little gull during the non-breeding period.  The estimated densities of little gull recorded at Inch Cape, Seagreen 1 and Seagreen 1a offshore wind farms were low and so few little gulls were recorded at rotor height at these wind farms collision risk modelling was not undertaken.  For Neart na Gaoithe offshore wind farm between four and six collisions were estimated per year, depending on the turbine scenarios, with all collisions predicted to occur in the non-breeding period.  Consequently, an in-combination collision scenario of approximately ten collision per year is predicted.  On the basis that 4.2% of the collisions could be birds from the SPA less than 0.5 collisions per year is predicted to impact on the Outer Firth of Forth and St Andrews Bay Complex SPA.
460. This is equivalent to 0.39% of the Outer Firth of Forth and St Andrews Bay Complex SPA citation population of 126 individuals.  This estimated level of impact is not predicted to lead to an adverse effect on Outer Firth of Forth and St Andrews Bay Complex SPA little gull population.

In-combination: Conclusion

461. The potential effects from the Proposed Development in-combination with other plans or programmes on the Outer Firth and Forth and St Andrews Bay Complex SPA little gull population are predicted to be small and temporary, impacting on a small proportion of the site population.  Given this, it is concluded that the effects from the Proposed Development in-combination would not result in an adverse effect on this population.

Assessment for the Common Gull Population

462. Common gull is both a breeding and winter visitor to Scottish coastal waters.  Generally, lower numbers of common gulls are present during the breeding period when they are breeding inland.  During the non-breeding period they occur largely within inshore and coastal waters and are infrequent further offshore (Forrester et al. 2007). 
463. The citation population of 14,647 individuals is based on winter gull surveys undertaken between 2003/04 and 2005/06 (NatureScot and JNCC 2022). Based on the WeBS counts data the population has remained relatively stable since 2001 (BTO 2022) (Figure 5.11).
464. Species specific advice in relation to common gull is to:

• Ensure common gull continue to have access to and can utilise all optimal habitats suitable for all relevant aspects of their life cycle associated with the site.
• Avoid significant disturbance to common gulls and ensure individuals can move safely between these areas within the site.

Figure 511: Common gull population trend at the Outer Firth of Forth and St Andrews Bay Complex SPA for the period 2001 - 2020. The orange line shows the population at the time of site designation peak mean of 14,647 individuals). Data are from the Wetland Bird Survey Database (BTO 2022).

The Potential for Impacts on the Common Gull Population

465. Potential impacts from the Proposed Development could arise during construction, operation and maintenance and decommissioning and could cause direct habitat loss, changes in prey availability and disturbance and displacement and collision impacts.  Consequently, the focus of the assessment for this SPA population is concerned with all the Conservation Objectives.
466. Common gulls were primarily recorded in the Offshore Ornithology Study Area during the non-breeding season in both years, with abundance peaking in December 2020 at 982 birds (95CI 232-1934). During inter-tidal and nearshore surveys common gulls were largely absent or recorded in low numbers throughout the year with an exception of 565 during December, the same period that the peak abundance occurred offshore.  Birds were mostly recorded out to 1 km from the shore, although were mainly recorded in the shallow nearshore waters between 0-500 m.

Project Alone: Construction and Decommissioning

Disturbance and Displacement

467. Direct disturbance and displacement to common gull during the construction phase may arise within the Proposed Development export cable corridor (and its immediate vicinity) as a result of increased vessel movements and helicopter activity, as well as from other activities directly associated with the installation of the export cable.
468. Reviews of the sensitivity of different seabird species to disturbance from vessels and helicopter traffic have assessed common gull as having relatively low sensitivity from disturbance arising from vessels (Furness et al. 2013).  Consequently, it is predicted that any disturbance or displacement impacts arising from the construction activities within the SPA would be localised and, should it occur, be temporary.
469. The potential for disturbance effects during decommissioning is assumed to be the same (or less) as for construction, noting that the duration of the decommissioning phase will not exceed that of construction, and may be shorter.
470. The maximum count of 565 common gulls recorded during nearshore and intertidal surveys is equivalent to 3.8% of the SPA population (based on winter gull survey population estimate).  Although birds present could be disturbed and displaced by the presence of vessel activity within the SPA, evidence shows that displacement is temporary and that birds that are displaced will be able to relocate to other locations within the SPA and return shortly after vessel activities cease.  On this basis it is considered that there is no potential for construction or decommissioning related disturbance or displacement to lead to an adverse effect on the Outer Firth of Forth and St Andrews Bay Complex SPA common gull population.

Changes to Prey Availability

471. Common gulls are opportunistic feeders and any changes in prey availability will be relatively localised and temporary.  Common gull occur widely in coastal waters across the SPA and therefore not restricted by prey availability and will be able to forage elsewhere if needed to. On this basis it is considered that there is no potential for construction or decommissioning related changes in prey availability to lead to an adverse effect on the Outer Firth of Forth and St Andrews Bay Complex SPA common gull population.

Direct Habitat Loss

472. Construction activities within the Outer Firth of Forth and St Andrews Bay Complex SPA could cause the loss of habitat which could impact on common gull.
473. Common gull feed on the sea surface and there will be no direct impact from the loss of habitat to common gull. On this basis it is considered that there is no potential for construction or decommissioning related habitat loss to lead to an adverse effect on the Outer Firth of Forth and St Andrews Bay Complex SPA common gull population.

Project Alone: Operation

Disturbance and Displacement

474. On-going routine maintenance could cause disturbance and displacement to common gull during the operation phase within the Proposed Development export cable corridor (and its immediate vicinity) as a result of increased vessel movements and helicopter activity, as well as from other activities directly associated with the maintenance of the export cable.
475. Common gull are recognised to have low sensitivity to disturbance and displacement and therefore any impacts will be temporary and birds will be able to relocate to undisturbed areas. On this basis it is considered that there is no potential for operational related disturbance or displacement to lead to an adverse effect on the Outer Firth of Forth and St Andrews Bay Complex SPA black-headed gull population.

Project Alone: Conclusion

476. The potential effects from the Proposed Development alone on the Outer Firth and Forth and St Andrews Bay Complex SPA common gull population are predicted to be small and temporary, impacting on a small proportion of the site population.  Given this, it is concluded that the effects from the Proposed Development alone would not result in an adverse effect on this population.

Effects In-Combination: Construction, Operation, Maintenance and Decommissioning

Disturbance and Displacement

477. During construction, operation and decommissioning phases there is potential existing marine traffic activity, including fishing and commercial vessels to cause disturbance and displacement impacts on common gull and therefore capable of causing an in-combination impact.  Marine traffic occurs widely throughout the region, including within the SPA (see Offshore EIA report volume 2, chapter 13) and the additional vessel activity arising during construction, operation and decommissioning will not make any material difference to the level of disturbance and displacement currently present within the SPA. It is predicted that the potential increase in disturbance and displacement will not be detectable against current levels and therefore will not cause an in-combination impact that would lead to an adverse effect on Outer Firth of Forth and St Andrews Bay Complex SPA common gull population.

Changes to Prey Availability

478. There is limited potential for in-combination impacts to affect prey availability within the Outer Firth and Forth and St Andrews Bay Complex SPA. Any impacts will be temporary with recovery following completion of the construction, operation and decommissioning activities.  There is limited, if any, potential for in-combination impacts that will cause a measurable effect on the prey of common gull and no in-combination impacts that would limit their ability to relocate temporarily to other locations within the SPA where common gull are known to occur. Consequently, there will be no in-combination impacts relating to changes in prey availability that would cause an adverse effect on the Outer Firth of Forth and St Andrews Bay Complex SPA common gull population.

Direct Habitat Loss

479. Existing and planned offshore wind farms: Inch Cape, Neart na Gaoithe, Seagreen 1 and Seagreen 1A could all have potential to cause in-combination impacts within the SPA (see Offshore EIA report volume 2, chapter 8).  During construction and decommissioning these impacts will be temporary and in-combination impacts would only occur if activities were undertaken within the SPA simultaneously or overlapping the recovery period.  It is predicted that all construction activities for other offshore wind farms that could cause an in-combination impact will be completed prior to the commencement of construction for the proposed Development.  There will be in-combination impacts during the operation and maintenance phases of the projects.
480. Potential impacts on habitat from the Project Alone has been identified as being temporary during construction and decommissioning and there is little potential for in-combination impacts to arise with other offshore wind farms due to their construction having been completed before construction commences at the Proposed Development and similarly decommissioning may have been completed by the other projects prior to the start of decommissioning by the proposed Development.  There is potential long-term habitat loss throughout the period of operation and maintenance when a potential loss of 0.09% of the SPA could be impacted due to cable protection.  The potential long-term loss of habitat associated with the other projects is unknown.  However, the long-term loss of habitat from cable protection does not equate to loss of habitat to common gull as they do not occur in the area where the majority of impacts on habitat from cable protection are predicted to occur. Furthermore the nearshore trenchless cabling will not impact on the habitats and it is the nearshore areas where common gull are known to most frequently occur.
481. The potential impacts on common gull will likely be undetectable and will not cause an in-combination impact that would lead to an adverse effect on Outer Firth of Forth and St Andrews Bay Complex SPA common gull population

In-combination: Conclusion

482. The potential effects from the Proposed Development in-combination with other plans or programmes on the Outer Firth and Forth and St Andrews Bay Complex SPA common gull population are predicted to be small and temporary, impacting on a small proportion of the site population.  Given this, it is concluded that the effects from the Proposed Development in-combination would not result in an adverse effect on this population.

Assessment for the Herring Gull Population

483. Herring gull occur widely across the east coast of Scotland both during the breeding and non-breeding periods.  Herring gull using the Outer Firth of Forth and St Andrews Bay Complex SPA include those breeding at the following SPAs:

• Forth Islands SPA;
• St Abb’s Head to Fast Castle SPA; and
• Fowlsheugh SPA.
  484. Consequently, these SPA populations are considered functionally linked to the Outer Firth of Forth and St Andrews Bay Complex SPA.
  485. No site-reference population is set for herring gull at the Outer Firth of Forth and St Andrews Bay Complex SPA due to the turnover of herring gulls within the foraging area. For breeding herring gull, when assessing plans or projects, the population impact should be considered in relation to the site reference populations for the above SPAs (NatureScot and JNCC 2022).
  486. Species specific advice for herring gull is to:

• Ensure breeding herring have the ability to recover at the relevant SPA breeding colonies.
• Ensure herring gull within Outer Firth of Forth and St Andrews Bay Complex SPA are not at significant risk from injury or mortality during the breeding and non-breeding seasons.
• Ensure herring gull can move safely between the site and important areas of functionally linked land outwith the site.

The Potential for Impacts on the Herring Gull Population

487. Potential impacts from the Proposed Development could arise during construction, operation and maintenance and decommissioning and could cause direct habitat loss, changes in prey availability and disturbance and displacement and collision impacts.  Consequently, the focus of the assessment for this SPA population is concerned with all the Conservation Objectives.
488. The potential impacts on herring gull for each of the SPAs that are functionally linked to the Outer Firth of Forth and St Andrews Bay Complex SPA have been assessed under each relevant SPA.  The conclusions for each assessment are presented in Table 5.6   Open ▸ and apply to both breeding and non-breeding populations during construction, operation and decommissioning phases.
489. The conclusions for each assessment for the Proposed Development in-combination with other plans or programmes are presented in
490. Table 5.7   Open ▸ and apply to breeding and non-breeding populations during construction, operation and decommissioning phases.

Table 5.6:  Potential for adverse effects on herring gull from SPAs functionally linked to the Outer Firth of Forth and St Andrews Bay Complex SPA.

Table 5.7:  Potential for in-combination adverse effects on herring gull from SPAs functionally linked to the Outer Firth of Forth and St Andrews Bay Complex SPA.

491. On the basis that no adverse effects have been identified for Forth Islands SPA, St Abb’s Head to Fast Castle SPA and Fowlsheugh SPA and these colonies are functionally linked to the Outer Firth of Forth and St Andrews Bay Complex SPA it is concluded that the effects from the Proposed Development alone and in-combination would not result in an adverse effect on herring gull at the Outer Firth of Forth and St Andrews Bay Complex SPA. This conclusion is supported by the assessments presented in sections 5.7.1 to 5.73 inclusive.

Assessment for the Arctic Tern Population

492. Arctic terns are a summer migrant to Scottish waters with bird arriving in mid-April and departing in early September.  The largest colony in the Forth and Tay area is in the Forth Islands SPA with a breeding population of 832 AoN in 2017.
493. The mean seasonal peak density was 0.06 birds/km2, equating to a mean seasonal peak population estimate for the Offshore Ornithology Study Area of 301 birds (95%CI 138 – 524). Peak abundances were recorded in late summer which can likely be attributed to adults and juveniles moving through the study area away from breeding colonies.
494. Arctic tern using the Outer Firth of Forth and St Andrews Bay Complex SPA include those breeding at the following SPA:

• Forth Islands SPA
  495. Consequently, this SPA population is considered functionally linked to the Outer Firth of Forth and St Andrews Bay Complex SPA.
  496. No site-reference population is set for Arctic tern at the Outer Firth of Forth and St Andrews Bay Complex SPA due to the turnover of Arctic tern within the foraging area. For breeding Arctic tern, when assessing plans or projects, the population impact should be considered in relation to the site reference population for the Forth Islands SPA (NatureScot and JNCC 2022).
  497. Site specific advice for Arctic tern is to:
• Ensure Arctic terns within Outer Firth of Forth and St Andrews Bay Complex SPA are not at significant risk from injury or mortality during the breeding season.
• Ensure Arctic tern can move safely between the site and important areas of functionally linked land outwith the site.

The Potential for Impacts on the Arctic tern Population

498. Potential impacts from the Proposed Development could arise during construction, operation and maintenance and decommissioning and could cause direct habitat loss, changes in prey availability and disturbance and displacement impacts.  Consequently, the focus of the assessment for this SPA population is concerned with all the Conservation Objectives.
499. The potential impacts on Arctic tern for the Forth Islands SPA the population of which is functionally linked to the Outer Firth of Forth and St Andrews Bay Complex SPA have been assessed.  The conclusions for each assessment are presented in Table 5.8   Open ▸ and apply to breeding populations during construction, operation and decommissioning phases.
500. The conclusions for each assessment for the Proposed Development in-combination with other plans or programmes are presented in Table 5.9   Open ▸ and apply to breeding and non-breeding populations during construction, operation and decommissioning phases.

Table 5.8:  Potential for adverse effects on Arctic tern from SPA functionally linked to the Outer Firth of Forth and St Andrews Bay Complex SPA.

Table 5.9:  Potential for in-combination adverse effects on Arctic tern from SPA functionally linked to the Outer Firth of Forth and St Andrews Bay Complex SPA.

501. On the basis that no adverse effects have been identified for Forth Islands SPA, and this colony is functionally linked to the Outer Firth of Forth and St Andrews Bay Complex SPA it is concluded that the effects from the Proposed Development alone and in-combination would not result in an adverse effect on Arctic tern at the Outer Firth of Forth and St Andrews Bay Complex SPA.

Assessment for the Common Tern Population

502. Common terns are a summer migrant to Scottish waters with bird arriving in April and departing in September. Birds were widespread throughout the Offshore Ornithology Study Area and the mean seasonal peak density was 0.06 birds/km2, equating to a mean seasonal peak population estimate for the Offshore Ornithology Study Area of 301 birds (95%CI 138 – 524). Most sightings occurred during the late breeding season, with peaks occurring in August.  These birds can likely be attributed to adults and juveniles moving through the study area away from breeding colonies.
503. Common terns are a qualifying species for the nearby Forth Islands SPA, which is estimated to hold around 3% of the GB population, corresponding to 334 pairs (mean 1997 – 2001; NatureScot, 2020). Leith docks, located in Edinburgh also supports a large breeding population, estimated to be at around 514 and 246 AON in 2018 and 2019 respectively (SMP, 2021), although the Offshore Ornithology Study Area is outwith the mean maximum foraging range (+1S.D) for birds from this colony
504. Common terns using the Outer Firth of Forth and St Andrews Bay Complex SPA include those breeding at the following SPAs:

• Forth Islands SPA; and
• Imperial Dock Lock SPA.
  505. Consequently, these SPA population are considered functionally linked to the Outer Firth of Forth and St Andrews Bay Complex SPA.
  506. No site-reference population is set for common tern at the Outer Firth of Forth and St Andrews Bay Complex SPA due to the turnover of common terns within the foraging area. For breeding common tern, when assessing plans or projects, the population impact should be considered in relation to the site reference population for the Forth Islands and Imperial Dock Lock SPAs (NatureScot and JNCC 2022).
  507. Species specific advice for comment tern is to:
• Ensure breeding common tern have the ability to recover at the relevant SPA breeding colonies.
• Ensure common terns within Outer Firth of Forth and St Andrews Bay Complex SPA are not at significant risk from injury or mortality during the breeding season.
• Ensure common tern can move safely between the site and important areas of functionally linked land outwith the site.

The Potential for Impacts on the Common Tern Population

508. Potential impacts from the Proposed Development could arise during construction, operation and maintenance and decommissioning and could cause direct habitat loss, changes in prey availability and disturbance and displacement impacts.  Consequently, the focus of the assessment for this SPA population is concerned with all the Conservation Objectives.
509. As outlined in section 3.1, it is considered that there is no pathway for effect on common terns breeding at Imperial Dock Lock SPA since the Proposed Development is situated well beyond the foraging range of common tern breeding at this SPA (based on colony tracking data and a mean maximum plus 1 SD foraging range of 18.0±8.9 km; Wilson et al. 2014; Woodward et al. 2019). Therefore, only potential impacts on common tern for the Forth Islands SPA have been assessed.  The conclusions for this assessment are presented in Table 5.10   Open ▸ and apply to the breeding population during construction, operation and decommissioning phases.
510. The conclusions for this assessment for the Proposed Development in-combination with other plans or programmes are presented in Table 5.11   Open ▸ and apply to breeding and non-breeding populations during construction, operation and decommissioning phases.

Table 5.10:  Potential for adverse effects on common tern from SPAs functionally linked to the Outer Firth of Forth and St Andrews Bay Complex SPA.

Table 5.11:  Potential for in-combination adverse effects on common tern from SPAs functionally linked to the Outer Firth of Forth and St Andrews Bay Complex SPA.

511. On the basis that no adverse effects have been identified for Forth Islands SPA or Leith Docks SPA, and these colonies are functionally linked to the Outer Firth of Forth and St Andrews Bay Complex SPA it is concluded that the effects from the Proposed Development alone or in-combination would not result in an adverse effect on common tern at the Outer Firth of Forth and St Andrews Bay Complex SPA.

Assessment for the Guillemot Population

512. Guillemots were the most abundant species, with peaks present in April, May and August and/or September in both years, coinciding with the start of the breeding season and the post-breeding flightless moult stage. April/May peaks coincide with the onset of egg-laying and incubation (Harris and Wanless, 2004). During this time, most birds were recorded as sitting on the water, which is to be expected considering their feeding strategy, in which they dive for prey from the water surface. The mean seasonal peak abundances for guillemots in the Offshore Ornithology Study Area during the breeding and non-breeding season, respectively, were 249,682 birds (95%CI 211,155 – 295,561) and 170,982 birds (95%CI 136,779 – 206,729).
513. Large breeding colonies in proximity to the Offshore Ornithology Study Area are present on the Isle of May and St Abb’s Head with approximately 18,705 and 42,905 individuals recorded in 2018 respectively (SMP, 2021).
514. Guillemot using the Outer Firth of Forth and St Andrews Bay Complex SPA include those breeding at the following SPAs:

• Forth Islands SPA;
• St Abb’s Head to Fast Castle SPA;
• Fowlsheugh SPA; and
• Buchan Ness to Collieston SPA.
  515. Consequently, these SPA populations are considered functionally linked to the Outer Firth of Forth and St Andrews Bay Complex SPA.
  516. No site-reference population is set for guillemot at the Outer Firth of Forth and St Andrews Bay Complex SPA due to the turnover of guillemot within the foraging area. For breeding guillemot, when assessing plans or projects, the population impact should be considered in relation to the site reference populations for the above SPAs (NatureScot and JNCC 2022).
  517. Species specific advice in relation to guillemot is to:
• Ensure guillemot within Outer Firth of Forth and St Andrews Bay Complex SPA are not at significant risk from injury or mortality during the breeding and non-breeding seasons.
• Ensure guillemot can move safely between the site and important areas of functionally linked land outwith the site.

The Potential for Impacts on the Guillemot Population

518. Potential impacts from the Proposed Development could arise during construction, operation and maintenance and decommissioning and could cause direct habitat loss, changes in prey availability and disturbance and displacement and collision impacts.  Consequently, the focus of the assessment for this SPA population is concerned with all the Conservation Objectives.
519. The potential impacts on guillemot for each of the SPAs that are functionally linked to the Outer Firth of Forth and St Andrews Bay Complex SPA have been assessed under each relevant SPA.  The conclusions for each assessment are presented in Table 5.12   Open ▸ and apply to both breeding and non-breeding populations during construction, operation and decommissioning phases.
520. The conclusions for each assessment for the Proposed Development in-combination with other plans or programmes are presented in Table 5.13   Open ▸ and apply to breeding and non-breeding populations during construction, operation and decommissioning phases.

Table 5.12:  Potential for adverse effects on guillemot from SPAs functionally linked to the Outer Firth of Forth and St Andrews Bay Complex SPA.* Adverse effect concluded under on the Scoping Approach only.

Table 5.13:  Potential for in-combination adverse effects on guillemot from SPAs functionally linked to the Outer Firth of Forth and St Andrews Bay Complex SPA. *Adverse effect concluded under on the Scoping Approach only.

521. The following conclusions are supported by the assessments presented in sections 5.7.1 to 5.73 inclusive, and section 5.7.5.
522. The potential effects from the Proposed Development alone and in-combination with other UK North Sea wind farms on the Forth Islands SPA guillemot population are predicted to be relatively small based on the Developer Approach. Given this, it is concluded that the effects from the Proposed Development alone and in-combination would not result in an adverse effect on this population. The Scoping Approach predicts greater effects from the Proposed Development alone and in-combination. However, it is considered that the level of effects on guillemots assumed by the Scoping Approach are overly precautionary and without any reasonable basis or support from the available evidence (volume 3, appendix 11.4, annex G of the Offshore EIA Report). Given this, it is considered that greater weight should be given to the conclusions as determined by the Developer Approach, which concluded no adverse effect on the Forth Islands SPA guillemot population as a result of the Proposed Development alone or in-combination with other UK North Sea wind farms.
523. The potential effects from the Proposed Development alone and in-combination with either the other Forth and Tay wind farms or the other UK North Sea wind farms are predicted to have the potential to result in marked reductions in the size of the St Abb’s Head to Fast Castle SPA kittiwake population relative to the population size in the absence of these effects. Although it is considered likely that the assessment is overly precautionary, the level of the predicted impact is such that there is considered to be the potential for an adverse effect on the St Abb’s Head to Fast Castle SPA kittiwake population as a result of the predicted Proposed Development alone and in-combination effects. This conclusion applies to the assessments undertaken according to both the Developer Approach and the Scoping Approach.
524. It is considered that the predicted levels of impact from the Proposed Development alone on the Fowlsheugh SPA kittiwake population are of a small (for the Developer Approach) to, at most, moderate scale (for the upper range of the Scoping Approach). It is therefore concluded that the effects from the Proposed Development alone would not result in an adverse effect on this SPA population. However, for both the Scoping and Developer Approaches, the predicted levels of impact associated with the two in-combination scenarios represent a marked increase compared to those associated with the Proposed Development alone. Consequently, it is concluded that there is the potential for an adverse effect on the Fowlsheugh kittiwake population as a result of the predicted effects from (i) the Proposed Development in-combination with the other Forth and Tay wind farms and (ii) the Proposed Development in-combination with the other UK North Sea wind farms.
525. On the basis that no adverse effects have been concluded for St Abb’s Head to Fast Castle SPA and Fowlsheugh SPA and that these colonies are functionally linked to the Outer Firth of Forth and St Andrews Bay Complex SPA cannot be concluded that the effects from the Proposed Development alone or in-combination would not result in an adverse effect on guillemot at the Outer Firth of Forth and St Andrews Bay Complex SPA.

Assessment for the Razorbill Population

526. Razorbills were present in relatively high abundances in the Offshore Ornithology Study Area, with birds recorded most frequently in October and September, during the non-breeding season. Mean seasonal peaks occurred during the non-breeding period with an estimated population of 48,899 birds (95%CI 32,543 – 68,240). Estimates during the breeding season were lower, calculated at 14,639 birds (95%CI 11,117 – 18,606).  Relatively lower abundances recorded during the summer suggests most birds at nearby colonies do not venture into the Offshore Ornithology Study Area to forage during chick-rearing and instead use the Offshore Ornithology Study Area during dispersal post-breeding. This is supported by increases in abundance towards the end of the breeding season.
527. No site-reference population is set for razorbill at the Outer Firth of Forth and St Andrews Bay Complex SPA in the non breeding season and there are no SPAs that are functionally linked with razorbill (NatureScot and JNCC 2022).
528. Site specific advice in relation ro razorbill is to:

• Ensure razorbill within Outer Firth of Forth and St Andrews Bay Complex SPA are not at significant risk from injury or mortality during the non-breeding season.
• Ensure razorbill can move safely between the site and important areas of functionally linked land outwith the site.

The Potential for Impacts on the Razorbill Population

529. Potential impacts from the Proposed Development could arise during construction, operation and maintenance and decommissioning and could cause direct habitat loss, changes in prey availability and disturbance and displacement.  Consequently, the focus of the assessment for this SPA population is concerned with all the Conservation Objectives.

Project Alone: Construction and Decommissioning

Disturbance and Displacement

530. Direct disturbance and displacement to razorbill during the construction phase may arise within the Proposed Development export cable corridor (and its immediate vicinity) as a result of increased vessel movements, as well as from other activities directly associated with the installation of the export cable.
531. Reviews of the sensitivity of different seabird species to disturbance from vessels have assessed razorbill as having a relative moderate sensitivity from disturbance arising from vessels (Furness et al. 2013).
532. The Proposed Development offshore export cable encompasses 168km2 and the total area of Outer Firth of Forth and St Andrews Complex SPA is 2,720.68 km2. Consequently, no more than 6.2% of the SPA will be affected by disturbance over the whole construction phase.  Construction activities will not occur simultaneously across the entirety of the Proposed Development export cable corridor but will be undertaken within discrete areas along the cable route corridor.
533. Studies undertaken indicate that razorbill may be displaced by vessel traffic with one study reporting individuals being flushed by approaching vessels at distances from between 30 m and 900 m and for flocks a median distance of 280 m (Fliessbach et al. 2019).
534. Consequently, the area of impact from a single vessel at any one time could vary from between 0.003 km2 to 2.55 km2 (based on the minimum and maximum reported disturbance distances), equivalent to between <0.001% and 0.09% of the SPA. During construction there is potential for up to 12 vessels to occur in the area.  On this basis a theoretical maximum area of disturbance of up to 30.6 km2 could occur, equivalent to 1.12% of the SPA.  However, during construction vessel activity will be clustered around the area of cable laying and therefore the areas of potential disturbance from each vessel will overlap and the overall area of disturbance will be considerably smaller.
535. Razorbill that are displaced could return to the area following the departure of the vessel.  Consequently, it is predicted that any disturbance or displacement impacts arising from the construction activities within the SPA could occur over a relatively limited area and would be temporary with no significant changes in the numbers present.
536. The potential for disturbance effects during decommissioning is assumed to be the same (or less) as for construction, noting that the duration of the decommissioning phase will not exceed that of construction, and may be shorter.
537. On the basis that the potential disturbance and displacement impacts will be temporary and will not cause change in the abundance within the SPA, it is considered that there is no potential for construction or decommissioning related disturbance or displacement to lead to an adverse effect on the Outer Firth of Forth and St Andrews Bay Complex SPA razorbill population.

Changes to Prey Availability

538. Razorbill prey primarily on sandeels but will also take other species in particular sprats and herring  (Harris and Wanless 1986, St. John Glew et al 2019).  Any changes in prey availability associated with the construction and decommissioning activities within the SPA will be relatively localised and temporary.  Razorbill occur widely across the SPA and are therefore not restricted by prey availability and are adapted to relocating elsewhere during periods of low prey availability (St. John Glew et al 2019). On this basis, although there could be a temporary change in the distribution of razorbills within the SPA it is considered that there is no potential for construction or decommissioning related changes in prey availability to lead to an adverse effect on the Outer Firth of Forth and St Andrews Bay Complex SPA razorbill population.

Direct Habitat Loss

539. Construction activities within the Outer Firth of Forth and St Andrews Bay Complex SPA could cause the loss of habitat which could impact on non-breeding razorbill.
540. Razorbill typically dive to depths of less than 15 m but can reach up to 47 m during the non-breeding season (Dunn et al. 2019).  Reviews of the sensitivity of different seabird species to habitat use flexibility assigned razorbill as ‘3’ on a five-scale ranking system. (Furness et al. 2013). Suggesting that razorbill are moderately sensitive to the loss of habitat.
541. The potential loss of 0.09% of the SPA due to cable protection and the potential temporary habitat loss caused by trenching and burying the cables will impact on a small proportion of the SPA razorbill population which will be able to relocate to other suitable areas until the habitat and associated prey, return to pre-construction levels. The impact will not lead to an adverse effect on the Outer Firth of Forth and St Andrews Bay Complex SPA populations of razorbill.

Project Alone: Operation

Disturbance and Displacement

542. On-going routine maintenance could cause disturbance and displacement to razorbill during the operation phase within the Proposed Development export cable corridor (and its immediate vicinity) as a result of increased vessel movements and helicopter activity, as well as from other activities directly associated with the maintenance of the export cable.
543. razorbill are recognised to be moderately sensitivity to disturbance and displacement and therefore any impacts will be temporary and birds will be able to relocate to undisturbed areas. On this basis it is considered that there is no potential for operational related disturbance or displacement to lead to an adverse effect on the Outer Firth of Forth and St Andrews Bay Complex SPA razorbill population.

Project Alone: Conclusion

544. The potential effects from the Proposed Development alone on the Outer Firth and Forth and St Andrews Bay Complex SPA non-breeding razorbill population are predicted to be small and temporary, impacting on a small proportion of the site population.  Given this, it is concluded that the effects from the Proposed Development alone would not result in an adverse effect on this population.

Effects In-Combination: Construction, Operation, Maintenance and Decommissioning

Disturbance and Displacement

545. During construction, operation and decommissioning phases there is potential for existing marine traffic activity, including fishing and commercial vessels to cause disturbance and displacement impacts on razorbill and therefore capable of causing an in-combination impact.  Marine traffic occurs widely throughout the region, including within the SPA (see Offshore EIA report volume 2, chapter 13) and the additional vessel activity arising during construction, operation and decommissioning will not make any material difference to the level of disturbance and displacement currently present within the SPA. It is predicted that the potential increase in disturbance and displacement will not be detectable against current levels and therefore will not cause an in-combination impact that would lead to an adverse effect on Outer Firth of Forth and St Andrews Bay Complex SPA razorbill population.

Changes to Prey Availability

546. There is limited potential for in-combination impacts to affect prey availability within the Outer Firth and Forth and St Andrews Bay Complex SPA. Any impacts will be temporary with recovery following completion of the construction, operation and decommissioning activities.  There is limited, if any, potential for in-combination impacts that will cause a measurable effect on the prey of razorbill and no in-combination impacts that would limit their ability to relocate temporarily to other locations within the SPA where razorbill are known to occur. Consequently, there will be no in-combination impacts relating to changes in prey availability that would cause an adverse effect on the Outer Firth of Forth and St Andrews Bay Complex SPA razorbill population.

Direct Habitat Loss

547. Existing and planned offshore wind farms: Inch Cape, Neart na Gaoithe, Seagreen 1 and Seagreen 1A could all have potential to cause in-combination impacts within the SPA (see Offshore EIA report volume 2, chapter 8).  During construction and decommissioning these impacts will be temporary and in-combination impacts would only occur if activities were undertaken within the SPA simultaneously or overlapping the recovery period.  It is predicted that all construction activities for other offshore wind farms that could cause an in-combination impact will be completed prior to the commencement of construction for the proposed Development.  There will be in-combination impacts during the operation and maintenance phases of the projects.
548. Potential impacts on habitat from the Project Alone has been identified as being temporary during construction and decommissioning and there is little potential for in-combination impacts to arise with other offshore wind farms due to their construction having been completed before construction commences at the Proposed Development and similarly decommissioning may have been completed by the other projects prior to the start of decommissioning by the proposed Development.  There is potential long-term habitat loss throughout the period of operation and maintenance when a potential loss of 0.09% of the SPA could be impacted due to cable protection.  The potential long-term loss of habitat associated with the other projects is unknown.
549. The potential impacts on razorbill will likely be undetectable and will not cause an in-combination impact that would lead to an adverse effect on Outer Firth of Forth and St Andrews Bay Complex SPA razorbill population.

In-combination: Conclusion

550. The potential effects from the Proposed Development in-combination with other plans or programmes on the Outer Firth and Forth and St Andrews Bay Complex SPA razorbill population are predicted to be small and temporary, impacting on a small proportion of the site population.  Given this, it is concluded that the effects from the Proposed Development in-combination would not result in an adverse effect on this population.

Assessment for the Puffin Population

551. Puffins were relatively abundant throughout the Offshore Ornithology Study Area, with density and population estimates suggesting the species utilises the area most frequently between March and September during the breeding season. Mean seasonal peaks were estimated as 12,290 birds (95%CI 9,857 – 14,997) in the breeding season and 20,667 birds (95%CI 17,298 – 24,031) in the non-breeding season. High abundances between May and August suggest birds at nearby colonies use the Offshore Ornithology Study Area to forage during chick rearing, with widespread dispersal towards the end of this period suggesting movement offshore to at-sea wintering areas
552. A large breeding colony is present on the Isle of May, with the most recent count of 39,200 Apparently Occupied Burrows in 2017 (AOB’s; SMP, 2021). Usually only present in coastal areas during the breeding season, puffins generally return to colonies between March and April, with egg laying occurring in April and May (Harris et al., 2010). Typically, adult birds return to the same burrow year-on-year, raising one chick which generally fledges between July and August (Anker-Nilssen and Røstad, 1993; Finney et al., 2003).
553. Typical prey species are small to mid-sized schooling pelagic fish, including sandeels and sprats, supplemented by crustaceans, molluscs and polychaetes during the breeding season (del Hoyo et al., 1996).
554. Puffin using the Outer Firth of Forth and St Andrews Bay Complex SPA include those breeding at the following SPA:

• Forth Islands SPA
  555. Consequently, this SPA population is considered functionally linked to the Outer Firth of Forth and St Andrews Bay Complex SPA.
  556. No site-reference population is set for puffin at the Outer Firth of Forth and St Andrews Bay Complex SPA due to the turnover of puffin within the foraging area. For breeding puffin, when assessing plans or projects, the population impact should be considered in relation to the site reference populations for the Forth Islands SPA (NatureScot and JNCC 2022).
  557. Site specific advice for puffin is to:
• Ensure puffin within Outer Firth of Forth and St Andrews Bay Complex SPA are not at significant risk from injury or mortality during the breeding and non-breeding seasons.
• Ensure puffin can move safely between the site and important areas of functionally linked land outwith the site.

The Potential for Impacts on the Puffin Population

558. Potential impacts from the Proposed Development could arise during construction, operation and maintenance and decommissioning and could cause direct habitat loss, changes in prey availability and disturbance and displacement and collision impacts.  Consequently, the focus of the assessment for this SPA population is concerned with all the Conservation Objectives.
559. The potential impacts on puffin for Forth Islands SPA that is functionally linked to the Outer Firth of Forth and St Andrews Bay Complex SPA have been assessed.  The conclusions for each assessment are presented in Table 5.14   Open ▸ and apply to both breeding and non-breeding populations during construction, operation and decommissioning phases.
560. The conclusions for each assessment for the Proposed Development in-combination with other plans or programmes are presented in Table 5.15   Open ▸ and apply to breeding and non-breeding populations during construction, operation and decommissioning phases.

Table 5.14:  Potential for adverse effects on puffin from SPAs functionally linked to the Outer Firth of Forth and St Andrews Bay Complex SPA.

Table 5.15:  Potential for in-combination adverse effects on puffin from SPAs functionally linked to the Outer Firth of Forth and St Andrews Bay Complex SPA.  *Adverse effect concluded under the Scoping Approach only.

561. The following conclusion is supported by the assessment presented in section 5.7.2 to 5.73 inclusive, and section 5.7.5.
562. Based on the Developer Approach, the potential effects from the Proposed Development in-combination with the other UK North Sea wind farms on the Forth Islands SPA puffin population are predicted to be small, as are the resultant population-level impacts. Given this, and the fact that this colony is functionally linked to the Outer Firth of Forth and St Andrews Bay Complex SPA, it is concluded that the effects from the Proposed Development in-combination with the other UK North Sea wind farms would not result in an adverse effect on the Outer Firth of Forth and St Andrews Bay Complex SPA.
563. As would be expected, the Scoping Approach predicts greater levels of effects and consequent population-level impacts than as predicted by the Developer Approach. Given this, it is concluded that for the Scoping Approach the possibility of an adverse effect on the SPA breeding population (and hence the Outer Firth of Forth and St Andrews Bay Complex SPA) cannot be excluded. This conclusion is considered to apply to the effects from the Proposed Development in-combination with the other Forth and Tay wind farms, as well as to the Proposed Development in-combination with the other UK North Sea wind farms (on the basis of the small difference in the predicted effects).
564. It is considered that the displacement and mortality rates used in the Scoping Approach are overly precautionary and are not supported by the available evidence (volume 3, appendix 11.4, annex G of the Offshore EIA Report). Therefore, it is considered that greater weight should be given to the conclusions as determined by the Developer Approach. On this basis, it is concluded that the effects from the Proposed Development in-combination with other plans or projects would not result in an adverse effect on puffin at the Outer Firth of Forth and St Andrews Bay Complex SPA.

Assessment for the Manx Shearwater Population

565. Manx shearwater densities were generally low with birds primarily observed during the breeding season, peaking in June. In these months, peak densities were 0.04 birds/km2 (95%CI 0.02 – 0.07) equating to a peak population estimate of 153 birds (95%CI 63 – 268). Mean peak population estimates for both years of surveys were calculated at 113 birds (95%CI 40 – 209) during the breeding season.
566. Although there is no site reference population the population at time of designation was 2,885 individuals (NatureScot 2020, NatureScot and JNCC 2022). There is currently insufficient information on Manx shearwater populations to assess a long-term UK trend, although indications from some of their main breeding colonies suggest an increasing trend (NatureScot and JNCC 2022).
567. The Manx shearwaters within the Outer Firth of Forth and St Andrews Bay Complex SPA may be a mixture of breeding birds from a mixture of colonies, sabbaticals, pre-breeding birds and possibly failed breeders.

The Potential for Impacts on the Manx Shearwater Population

568. Potential impacts from the Proposed Development could arise during construction, operation and maintenance and decommissioning and could cause direct habitat loss, changes in prey availability and disturbance and displacement.  Consequently, the focus of the assessment for this SPA population is concerned with all the Conservation Objectives.

Disturbance and Displacement

569. Direct disturbance and displacement to Manx shearwater during the construction phase may arise within the Proposed Development export cable corridor (and its immediate vicinity) as a result of increased vessel movements and helicopter activity, as well as from other activities directly associated with the installation of the export cable.
570. Manx shearwater are highly mobile foragers that spend significant proportions of time in flight. Reviews of the sensitivity of different seabird species to disturbance from vessels and helicopter traffic have assessed Manx shearwater as having very low sensitivity from disturbance arising from vessels (Furness et al. 2013).  Consequently, it is predicted that any disturbance or displacement impacts arising from the construction activities within the SPA would be localised and, should it occur, be temporary.
571. The potential for disturbance effects during decommissioning is assumed to be the same (or less) as for construction, noting that the duration of the decommissioning phase will not exceed that of construction, and may be shorter.
572. On the basis that Manx shearwater are not sensitive to disturbance or displacement and any impacts would be localised and temporary it is considered that there is no potential for construction or decommissioning related disturbance or displacement to lead to an adverse effect on the Outer Firth of Forth and St Andrews Bay Complex SPA Manx shearwater population.

Changes to Prey Availability

573. Manx shearwater are opportunistic feeders and do not entirely rely on fish in their diet and are pursuit-plunging or pursuit-diving specialists and reported to forage to depths of up to 55 m (Shoji et al. 2016). They also show flexibility with respect to foraging areas and not restricted to limited areas. Any changes in prey availability caused by construction or decommissioning activities within the SPA will be relatively localised and temporary and Manx shearwater will be able to forage elsewhere over a wide area. On this basis it is considered that there is no potential for construction or decommissioning related changes in prey availability to lead to an adverse effect on the Outer Firth of Forth and St Andrews Bay Complex SPA Manx shearwater population.

Direct Habitat Loss

574. Construction activities within the Outer Firth of Forth and St Andrews Bay Complex SPA could cause the loss of habitat which could impact on Manx shearwater.
575. As there will be no direct impact from the loss of habitat to Manx shearwater it is considered that there is no potential for construction or decommissioning related habitat loss to lead to an adverse effect on the Outer Firth of Forth and St Andrews Bay Complex SPA Manx shearwater population.

Project Alone: Operation

Disturbance and Displacement

576. On-going routine maintenance could cause disturbance and displacement to Manx shearwater during the operation phase within the Proposed Development export cable corridor (and its immediate vicinity) as a result of increased vessel movements and helicopter activity, as well as from other activities directly associated with the maintenance of the export cable.
577. Manx shearwater are recognised to have very low sensitivity to disturbance and displacement and therefore any impacts will be temporary and birds will be able to relocate to undisturbed areas. On this basis it is considered that there is no potential for operational related disturbance or displacement to lead to an adverse effect on the Outer Firth of Forth and St Andrews Bay Complex SPA Manx shearwater population.

Project Alone: Conclusion

578. The potential effects from the Proposed Development alone on the Outer Firth and Forth and St Andrews Bay Complex SPA Manx shearwater population are predicted to be small and temporary, impacting on a small proportion of the site population.  Given this, it is concluded that the effects from the Proposed Development alone would not result in an adverse effect on this population.

Effects In-Combination: Construction, Operation, Maintenance and Decommissioning

Disturbance and Displacement

579. During construction, operation and decommissioning phases there is potential for existing marine traffic activity, including fishing and commercial vessels to cause disturbance and displacement impacts on Manx shearwater and therefore capable of causing an in-combination impact.  Marine traffic occurs widely throughout the region, including within the SPA (see Offshore EIA report volume 2, chapter 13) and the additional vessel activity arising during construction, operation and decommissioning will not make any material difference to the level of disturbance and displacement currently present within the SPA. It is predicted that the potential increase in disturbance and displacement will not be detectable against current levels and therefore will not cause an in-combination impact that would lead to an adverse effect on Outer Firth of Forth and St Andrews Bay Complex SPA Manx shearwater population.

Changes to Prey Availability

580. There is limited potential for in-combination impacts to affect prey availability within the Outer Firth and Forth and St Andrews Bay Complex SPA. Any impacts will be temporary with recovery following completion of the construction, operation and decommissioning activities.  There is limited, if any, potential for in-combination impacts that will cause a measurable effect on the prey of Manx shearwater and no in-combination impacts that would limit their ability to relocate temporarily to other locations within the SPA where Manx shearwater are known to occur. Consequently, there will be no in-combination impacts relating to changes in prey availability that would cause an adverse effect on the Outer Firth of Forth and St Andrews Bay Complex SPA Manx shearwater population.

Direct Habitat Loss

581. Existing and planned offshore wind farms: Inch Cape, Neart na Gaoithe, Seagreen 1 and Seagreen 1A could all have potential to cause in-combination impacts within the SPA (see Offshore EIA report volume 2, chapter 8).  During construction and decommissioning these impacts will be temporary and in-combination impacts would only occur if activities were undertaken within the SPA simultaneously or overlapping the recovery period.  It is predicted that all construction activities for other offshore wind farms that could cause an in-combination impact will be completed prior to the commencement of construction for the proposed Development.  There will be in-combination impacts during the operation and maintenance phases of the projects.
582. Potential impacts on habitat from the Project Alone has been identified as being temporary during construction and decommissioning and there is little potential for in-combination impacts to arise with other offshore wind farms due to their construction having been completed before construction commences at the Proposed Development and similarly decommissioning may have been completed by the other projects prior to the start of decommissioning by the proposed Development.  There is potential long-term habitat loss throughout the period of operation and maintenance when a potential loss of 0.09% of the SPA could be impacted due to cable protection.  The potential long-term loss of habitat associated with the other projects is unknown. 
583. The potential impacts on Manx shearwater will likely be undetectable and will not cause an in-combination impact that would lead to an adverse effect on Outer Firth of Forth and St Andrews Bay Complex SPA Manx shearwater population.

In-combination: Conclusion

584. The potential effects from the Proposed Development in-combination with other plans or programmes on the Outer Firth and Forth and St Andrews Bay Complex SPA Manx shearwater population are predicted to be small and temporary, impacting on a small proportion of the site population.  Given this, it is concluded that the effects from the Proposed Development in-combination would not result in an adverse effect on this population.

Assessment for the Shag Population

585. Shags were only recorded twice in the Offshore Ornithology Study Area, on the June 2019 and December 2020 surveys. Design-based density estimates for June 2019 were 0.01 birds/km2 (95%CI 0.00 – 0.02), equating to a population estimate of 25 birds (95% CI 0 –72). The mean seasonal peak population estimate for the breeding season was 12 birds (95% CI 0 – 36) compared to the non-breeding season, where 5 birds (95%CI 0 – 12) were estimated to be present.
586. During intertidal and nearshore surveys shags were present in the Survey Area throughout the year, although numbers were generally low. Typically there were no more than eleven individuals recorded and a peak count of 21 in April.  The majority of shags were observed within 0-500m from the shore.
587. Shag using the Outer Firth of Forth and St Andrews Bay Complex SPA include those breeding at the following SPA:

• Forth Islands SPA.
  588. Consequently, this SPA population is considered functionally linked to the Outer Firth of Forth and St Andrews Bay Complex SPA.
  589. No site-reference population is set for shag at the Outer Firth of Forth and St Andrews Bay Complex SPA due to the turnover of shags within the foraging area. For breeding shag, when assessing plans or projects, the population impact should be considered in relation to the site reference populations for the above SPA (NatureScot and JNCC 2022).
  590. The population has declined since designation (Figure 5.12).

Figure 512: Shag population trend at the Forth Islands SPA for the period 2001 - 2020. The orange line shows the population at the time of site designation 2,400 individuals). Data are from the Seabird Monitoring Programme Database (SMP 2022).

591. Species specific advice in relation to shag is to:

• Ensure breeding European shag have the ability to recover at the relevant SPA breeding colonies.
• Ensure European shags within Outer Firth of Forth and St Andrews Bay Complex SPA are not at significant risk from injury or mortality during the breeding and non-breeding seasons.
• Ensure European shags can move safely between the site and important areas of functionally linked land outwith the site.

The Potential for Impacts on the Shag Population

592. Potential impacts from the Proposed Development could arise during construction, operation and maintenance and decommissioning and could cause direct habitat loss, changes in prey availability and disturbance and displacement.  Consequently, the focus of the assessment for this SPA population is concerned with all the Conservation Objectives.

Project Alone: Construction and Decommissioning

Disturbance and Displacement

593. Direct disturbance and displacement to shag during the construction phase may arise within the Proposed Development export cable corridor (and its immediate vicinity) as a result of increased vessel movements and helicopter activity, as well as from other activities directly associated with the installation of the export cable.
594. Reviews of the sensitivity of different seabird species to disturbance from vessels have assessed shag as having a relative moderate sensitivity from disturbance arising from vessels (Furness et al. 2013).
595. The Proposed Development offshore export cable encompasses 168km2 and the total area of Outer Firth of Forth and St Andrews Complex SPA is 2,720.68 km2. Consequently, no more than 6.2% of the SPA will be affected by disturbance over the whole construction phase.  Construction activities will not occur simultaneously across the entirety of the Proposed Development export cable corridor but will be undertaken within discrete areas along the cable route corridor.
596. Studies indicate that shag may be disturbed by motorised craft at a mean distance of 500 m.  Although flight responses are typically occur when a vessel is within 200 – 300 m (Goodship and Furness 2019, Jarrett et al. 2018).
597. Consequently, the area of impact from a single vessel at any one time is estimated to be 0.78 km2 (based on the mean reported disturbance distance of 500 m), equivalent to between <0.028% of the SPA. During construction there is potential for up to 12 vessels to occur in the area.  On this basis a theoretical maximum area of disturbance of up to 9.36 km2 could occur, equivalent to 0.34% of the SPA.  However, during construction vessel activity will be clustered around the area of cable laying and therefore the areas of potential disturbance from each vessel will overlap and the overall area of disturbance will be considerably smaller
598. Shags that are displaced could return to the area following the departure of the vessel with one study reporting no significant reduction in the number of birds present within 30 minutes of a vessel disturbance (Jarrett et al. 2018).  Consequently, it is predicted that any disturbance or displacement impacts arising from the construction activities within the SPA could occur over a relatively limited area and would be temporary with no significant changes in the numbers present.
599. The potential for disturbance effects during decommissioning is assumed to be the same (or less) as for construction, noting that the duration of the decommissioning phase will not exceed that of construction, and may be shorter.
600. On the basis that the potential disturbance and displacement impacts will be temporary and will not cause change in the abundance within the SPA, it is considered that there is no potential for construction or decommissioning related disturbance or displacement to lead to an adverse effect on the Outer Firth of Forth and St Andrews Bay Complex SPA shag population.

Changes to Prey Availability

601. Shag prey on a wide variety of fish species in particular sandeels (Wanless et al 1997) but are adaptable and opportunistic taking a broad range of prey items (Swan et al. 2008, Hillersøy and Lorentsen 2012).  Any changes in prey availability associated with the construction and decommissioning activities within the SPA will be relatively localised and temporary.  As outlined in the section on project alone: operation and maintenance – changes to prey availability for eider, shag occur widely across the SPA and are therefore not restricted by prey availability and are adapted to relocating elsewhere during periods of low prey availability. On this basis, although there could be a temporary change in the distribution of shag within the SPA it is considered that there is no potential for construction or decommissioning related changes in prey availability to lead to an adverse effect on the Outer Firth of Forth and St Andrews Bay Complex SPA shag population.

Direct Habitat Loss

602. Construction activities within the Outer Firth of Forth and St Andrews Bay Complex SPA could cause the loss of habitat which could impact on shag.
603. Shag typically occur in water depths of between 10 and 40 m, although can forage in water depths of up to 50 m (Daunt et al. 2015).  They avoid muddy sediments and reviews of the sensitivity of different seabird species to habitat use flexibility assigned razorbill as ‘3’ on a five-scale ranking system. (Furness et al. 2013, Daunt et al. 2015), suggesting that shag are moderately sensitive to the loss of habitat.
604. The potential loss of 0.09% of the SPA due to cable protection and the potential temporary habitat loss caused by trenching and burying the cables will impact on a small proportion of the SPA shag population which will be able to relocate to other suitable areas until the habitat and associated prey, return to pre-construction levels. The impact will not lead to an adverse effect on the Outer Firth of Forth and St Andrews Bay Complex SPA populations of shag.

Project Alone: Operation

Disturbance and Displacement

605. On-going routine maintenance could cause disturbance and displacement to shag during the operation phase within the Proposed Development export cable corridor (and its immediate vicinity) as a result of increased vessel movements and helicopter activity, as well as from other activities directly associated with the maintenance of the export cable.
606. Shag are recognised to be moderately sensitivity to disturbance and displacement and therefore any impacts will be temporary and birds will be able to relocate to undisturbed areas. On this basis it is considered that there is no potential for operational related disturbance or displacement to lead to an adverse effect on the Outer Firth of Forth and St Andrews Bay Complex SPA shag population.

Changes to Prey Availability

607. As outlined in the section on project alone: operation and maintenance – changes to prey availability for eider, there will be no increase in the potential for temporary changes in prey availability caused by impacts during operating and maintenance phases. Consequently, it is considered that there is no potential for operational or maintenance related changes in prey availability to lead to an adverse effect on the Outer Firth of Forth and St Andrews Bay Complex SPA shag population.

Project Alone: Conclusion

608. The potential effects from the Proposed Development alone on the Outer Firth and Forth and St Andrews Bay Complex SPA non-breeding shag population are predicted to be small and temporary, impacting on a small proportion of the site population.  Given this, it is concluded that the effects from the Proposed Development alone would not result in an adverse effect on this population.

Effects In-Combination: Construction, Operation, Maintenance and Decommissioning

Disturbance and Displacement

609. There is potential for existing marine traffic activity, including fishing and commercial vessels to cause disturbance and displacement impacts on shag and therefore capable of causing an in-combination impact.  Marine traffic occurs widely throughout the region, including within the SPA (see Offshore EIA report volume 2, chapter 13) and the additional vessel activity arising during construction, operation and decommissioning will not make any material difference to the level of disturbance and displacement currently present within the SPA. It is predicted that the potential increase in disturbance and displacement will not be detectable against current levels and therefore will not cause an in-combination impact that would lead to an adverse effect on Outer Firth of Forth and St Andrews Bay Complex SPA shag population.

Changes to Prey Availability

610. There is limited potential for in-combination impacts to affect prey availability within the Outer Firth and Forth and St Andrews Bay Complex SPA. Any impacts will be temporary with recovery following completion of the construction, operation and decommissioning activities.  There is limited, if any, potential for in-combination impacts that will cause a measurable effect on the prey of shag and no in-combination impacts that would limit their ability to relocate temporarily to other locations within the SPA where shag are known to occur. Consequently, there will be no in-combination impacts relating to changes in prey availability that would cause an adverse effect on the Outer Firth of Forth and St Andrews Bay Complex SPA shag population.

Direct Habitat Loss

611. Existing and planned offshore wind farms: Inch Cape, Neart na Gaoithe, Seagreen 1 and Seagreen 1A could all have potential to cause in-combination impacts within the SPA (See Offshore EIA Report, volume 2, chapter 8). During construction and decommissioning these impacts will be temporary and in-combination impacts would only occur if activities were undertaken within the SPA simultaneously or overlapping the recovery period.  There is uncertainty on when activities may be undertaken that could cause an in-combination impact but these will occur during the operation and maintenance phases of the projects.  Potential loss of habitat from the Project Alone has been identified as being temporary during construction and decommissioning with a potential loss of 0.09% of the SPA due to cable protection throughout the period of operation and maintenance.  The potential impacts on shag will likely be undetectable and will not cause an in-combination impact that would lead to an adverse effect on Outer Firth of Forth and St Andrews Bay Complex SPA shag population.

In-combination: Conclusion

612. The potential effects from the Proposed Development in-combination with other plans or programmes on the Outer Firth and Forth and St Andrews Bay Complex SPA shag population are predicted to be small and temporary, impacting on a small proportion of the site population.  Given this, it is concluded that the effects from the Proposed Development in-combination would not result in an adverse effect on this population.

Assessment for the Gannet Population

613. Gannets were most abundant in the Offshore Ornithology Study Area in the breeding season. Design-based analysis estimated gannet density to range between 0.00 birds/km2 (95%CI 0.00 – 0.01; February 2020) and 4.06 birds/km2 (95%CI 3.42 – 4.79; August 2019) in 2019/20 and 0.05 birds/km2 (95%CI 0.02 – 0.09; February 2021) and 3.27 birds/km2 (95%CI 2.88 – 3.68; July 2020) in 2020/21. Densities peaked in July and August.
614. Gannets were regularly present throughout the nearshore an intertidal surveys throughout the year with a peak of 978 birds was recorded in September.  The majority of birds were observed in flight between 1km and 1.5km offshore
615. Gannet using the Outer Firth of Forth and St Andrews Bay Complex SPA include those breeding at the following SPAs:

• Forth Islands SPA,
  616. Consequently, this SPA population is considered functionally linked to the Outer Firth of Forth and St Andrews Bay Complex SPA.
  617. No site-reference population is set for gannet at the Outer Firth of Forth and St Andrews Bay Complex SPA due to the turnover of gannet within the foraging area. For breeding gannet, when assessing plans or projects, the population impact should be considered in relation to the site reference populations for the Forth Islands SPA (NatureScot and JNCC 2022).
  618. Species specific advice for gannet is to:
• Ensure gannet within Outer Firth of Forth and St Andrews Bay Complex SPA are not at significant risk from injury or mortality during the breeding and non-breeding seasons.
• Ensure gannet can move safely between the site and important areas of functionally linked land outwith the site.

The Potential for Impacts on the Gannet Population

619. Potential impacts from the Proposed Development could arise during construction, operation and maintenance and decommissioning and could cause direct habitat loss, changes in prey availability and disturbance and displacement and collision impacts.  Consequently, the focus of the assessment for this SPA population is concerned with all the Conservation Objectives.
620. The potential impacts on gannet for each of the SPAs that are functionally linked to the Outer Firth of Forth and St Andrews Bay Complex SPA have been assessed under each relevant SPA.  The conclusions for each assessment are presented in Table 5.16   Open ▸ and apply to both breeding and non-breeding populations during construction, operation and decommissioning phases.
621. The conclusions for each assessment for the Proposed Development in-combination with other plans or programmes are presented in Table 5.17   Open ▸ and apply to breeding and non-breeding populations during construction, operation and decommissioning phases.

Table 5.16:  Potential for adverse effects on gannet from SPAs functionally linked to the Outer Firth of Forth and St Andrews Bay Complex SPA.

Table 5.17:  Potential for adverse in-combination effects on gannet from SPAs functionally linked to the Outer Firth of Forth and St Andrews Bay Complex SPA.

622. On the basis that no adverse effects have been identified for Forth Islands SPA and that this colony is functionally linked to the Outer Firth of Forth and St Andrews Bay Complex SPA it is concluded that the effects from the Proposed Development alone and in-combination with other plans or programmes would not result in an adverse effect on gannet at the Outer Firth of Forth and St Andrews Bay Complex SPA.