Changes to Prey Availability
  1. Potential impacts on key prey species for razorbills breeding at East Caithness Cliffs SPA during the operational and maintenance phase have been assessed in volume 2, chapter 9 of the Offshore EIA Report using the appropriate maximum design scenarios for these receptors. Reduction or disruption to prey availability through temporary and long-term subtidal habitat loss/disturbance, increased SSC and deposition, reductions in water clarity, EMF from subsea electrical cabling, and colonisation of subsea structures, could affect razorbill survival and productivity in the East Caithness Cliffs SPA population.
  2. The same evidence basis and context in relation to this effect pathway for the operation and maintenance phase applies to the East Caithness Cliffs SPA razorbill population as to the St Abb’s Head to Fast Castle SPA razorbill population. This is detailed in the section on Project Alone: Operation and Maintenance – Changes to Prey Availability for the St Abb’s Head to Fast Castle SPA population.
  3. Given this, it is considered that there is relatively little potential for the East Caithness Cliffs SPA razorbill population to be affected by changes to prey availability during the operation and maintenance phase, with any such effects being largely intermittent across a relatively small spatial extent. 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 East Caithness Cliffs SPA razorbill population.
Project Alone: Population-level Impacts
  1. As determined above, the effects from the Proposed Development alone which could lead to an adverse effect on the East Caithness Cliffs SPA razorbill population are limited to displacement/barrier effects during the operation and maintenance phase. For other effect pathways, there is considered to be no potential for an adverse effect on this population as a result of the Proposed Development alone, with any such effects likely to be small and of little, or no, consequence in terms of impacts at the population level.
  2. Given this, PVA was undertaken on the mortality to the adult and immature age classes predicted due to the displacement effects associated with the Proposed Development, as determined by both the Scoping and Developer Approaches (see Table 5.173   Open ▸ above). The population model for the SPA population was a stochastic, density independent, matrix model, based upon the demographic parameters specified in Table 2.19 of Offshore EIA Report, volume 3, appendix 11.6. The starting population size was the 2015 count for the SPA, with the projected population trends considered over a 35-year timescale (Offshore EIA Report, volume 3, appendix 11.5). The approach and methods to undertaking the PVA are as described in the section on Project Alone: Population-Level Impacts for St Abb’s Head to Fast Castle SPA razorbill population above, with further details provided in the Offshore EIA Report, volume 3, appendix 11.6).
  3. Outputs from the PVA are summarised according to the median predicted population-sizes at the end of the projection period, and the three metrics which the Scoping Opinion (Offshore EIA Report, volume 3, appendix 6.2) advised should be used for the interpretation of outputs and which have been shown to have relatively low sensitivity to factors such as varying population status and the mis-specification of the demographic rates underpinning the population model (Cook and Robinson 2015, Jitlal et al., 2017). These metrics are:
  • The CPS – the median of the ratio of the end-point size of the impacted to un-impacted (or baseline) population, expressed as a proportion;
  • The CPGR - the median of the ratio of the annual growth rate of the impacted to un-impacted population, expressed as a proportion; and
  • The centile of the un-impacted population that matches the median (i.e. 50th centile) of the impacted population (based upon the distribution of the end-point population-sizes generated by the multiple replications of the model runs, the value should always be less than 50 because the median for the impacted population is not expected to exceed that for the un-impacted population).

 

Table 5.174:
Projected 35-year population sizes and associated PVA metrics for the East Caithness Cliffs SPA razorbill population under different impact scenarios for the Proposed Development alone.

Table 5.174: Projected 35-year population sizes and associated PVA metrics for the East Caithness Cliffs SPA razorbill population under different impact scenarios for the Proposed Development alone.

  1. The PVA predicted that the East Caithness Cliffs SPA razorbill population would increase over the 35 year projection period irrespective of the effects from the Proposed Development. Thus, the population is predicted to be nearly twice as large than the current estimate of 40,117 adult birds under all scenarios, including the baseline which assumes no wind farm effects ( Table 5.174   Open ▸ ). Although the predicted increases in population size are inevitably greatest for the baseline scenario (because the PVAs are based on density independent models, which assume all mortality from the wind farm effects is additive and that there are no compensatory mechanisms operating within the population), the differences with the impact scenarios are small. The predicted levels of increase are unlikely to occur in reality (and are, in part, a consequence of the absence of any compensatory density dependence within the models – see the explanatory text under Project Alone: Population-Level Impacts for St Abb’s Head to Fast Castle SPA kittiwake population).
  2. The predicted population-level impacts are small, irrespective of whether these are determined using the Developer or Scoping Approaches. Thus, for the higher mortality rates for Scoping Approach B, the CPS value indicates that the displacement effects from the Proposed Development alone would result in a reduction of 1.4% in the size of the SPA population after 35 years, relative to that in the absence of any wind farm effects ( Table 5.174   Open ▸ ). The associated reduction in annual population growth rate (relative to that predicted under baseline conditions) is estimated to be zero, whilst the centile value of 48.7 indicates a high degree of overlap in the distributions of the predicted impacted and un-impacted population sizes and, hence, a high likelihood of the impacted population being of a similar size to the un-impacted population after 35 years. As would be expected, the metrics as determined from either the lower mortality rates of the Scoping Approach or the Developer Approach suggest even smaller levels of impact ( Table 5.174   Open ▸ ).
  3. For the same reasons as described in the section on Project-Alone: Population-Level Impacts for the St Abb’s Head to Fast Castle SPA razorbill population, the assessment of the East Caithness Cliffs SPA razorbill population incorporates high levels of precaution, which extend beyond the differences between the Developer and Scoping Approaches that are outlined above (and detailed in the Offshore EIA Report, volume 3, appendix 11.4). Notably, the concerns over the extent to which the seasonal mean peak abundances (which provide the basis for the displacement mortality estimates) are likely to be representative of the overall usage of the Proposed Development array and two kilometre buffer by razorbill are equally relevant to the East Caithness Cliffs SPA population as to the St Abb’s Head to Fast Castle SPA population. The evidence available from tracking data suggests that levels of usage of the Proposed Development array area and two kilometre buffer during the breeding season by razorbills from the East Caithness Cliffs SPA are likely to be very low (Wakefield et al. 2017).
Project Alone: Conclusion
  1. It is considered that the predicted levels of impact from the Proposed Development alone on the East Caithness Cliffs SPA razorbill population are of a small scale, as determined by both the Developer and Scoping Approaches. For both the Developer and Scoping Approaches it is also the case that the centile metric indicates a high likelihood of the impacted population being of similar size to the un-impacted population after 35 years. These levels of impact are within the context of an assessment which incorporates high levels of precaution (particularly as determined by the Scoping Approach). Given this, it is concluded that the effects from the Proposed Development alone (as determined by either the Developer or Scoping Approaches) would not result in an adverse effect on this SPA population.
Effects In-Combination
Effects of relevance to the in-combination assessment
  1. As detailed above, any effects from the Proposed Development alone on the East Caithness Cliffs SPA razorbill population during construction and decommissioning and resulting from disturbance and changes to prey availability during operation and maintenance will be small and highly localised. As such, there is considered to be no potential for these effect pathways to add to impacts at the population-level that might result from other effects pathways associated with the Proposed Development or from the effects due to other plans and projects.
  2. Therefore, the potential for effects of the Proposed Development to act on the East Caithness Cliffs SPA razorbill population in-combination with other plans and projects is limited to the displacement/barrier effect pathway during operation and maintenance. The following sections consider these potential effects for the Proposed Development in-combination with the other UK North Sea wind farms.
Displacement/Barrier Effects – Operation and Maintenance
  1. As described in the Offshore EIA Report, volume 3, appendix 11.6, annex E, estimates of breeding season displacement mortality which had been attributed to the East Caithness Cliffs SPA razorbill population were extracted from the existing assessments for offshore wind farms that are in planning, consented, under construction or in operation. As for the potential displacement mortality estimated for the Proposed Development ( Table 5.173   Open ▸ ), the mortality attributed to the SPA population from other offshore wind farms was estimated using the SNCB matrix approach, with details on the displacement and mortality rates that had been applied being available in each case. Thus, it was possible to adjust the estimated mortalities from each of the other projects to align with the displacement and mortality rates on which the Scoping and Developer Approaches are based.
  2. For the non-breeding periods, razorbill numbers associated with other offshore wind farms that are in planning, consented, under construction or in operation were extracted for each of the relevant seasonal periods from the cumulative totals collated for the East Anglia TWO and East Anglia ONE North submissions (MacArthur Green and Royal HaskoningDHV 2021, see Offshore EIA Report, volume 3, appendix 11.6, annex E for more details). The cumulative numbers for each of the non-breeding periods were apportioned to the East Caithness Cliffs SPA razorbill population according to the BDMPS approach (Furness 2015), with the subsequent displacement mortality calculated according to the displacement and mortality rates appropriate to each of the Scoping and Developer Approaches ( Table 5.175   Open ▸ ).

 

Table 5.175:
Estimated annual mortality of East Caithness Cliffs SPA razorbills as a result of displacement from the Proposed Development array area and 2 km buffer as determined by the Scoping Approach and Developer Approach, in-combination with the other UK North Sea wind farms.

Table 5.175: Estimated annual mortality of East Caithness Cliffs SPA razorbills as a result of displacement from the Proposed Development array area and 2 km buffer as determined by the Scoping Approach and Developer Approach, in-combination with the other UK North Sea wind farms.

  1. The additional annual mortality of adult razorbills from the East Caithness Cliffs SPA population predicted due to displacement from the Proposed Development in-combination with the other UK North Sea wind farms represents 0.12% of the current adult breeding population at this colony (i.e. 40,117 individuals – Table 3.3 of the Offshore EIA Report, volume 3, appendix 11.5) as determined by the Developer Approach, and between approximately 0.28 – 0.57% of this population as determined by the lower and upper estimates from the Scoping Approach. In terms of percentage increases in the baseline annual adult mortality of the population (which is based on applying a mortality rate of 0.09 – see Table 2.19 in he Offshore EIA Report, volume 3, appendix 11.6), the estimates of adult displacement mortality equate to an increase of 1.3% for the Developer Approach and of 3.1 – 6.3% for the lower and upper estimates from the Scoping Approach.
  2. The potential levels of impact on the East Caithness SPA razorbill population resulting from the mortality predicted from displacement and barrier effects associated with the Proposed Development in-combination with the other UK North Sea wind farms during the operation and maintenance phase are considered in more detail below in the Effects In-Combination: Population-Level Impacts section. This presents the outputs from PVAs of the potential effects of predicted displacement mortality on the SPA population.
In-Combination: Population-Level Impacts
  1. As for the Proposed Development alone, PVA was undertaken on the mortality to the adult and immature age classes predicted due to the displacement effects associated with the Proposed Development in-combination with the other UK North Sea wind farms. This was on the basis of the potential mortality as determined by both the Scoping and Developer Approaches (see Table 5.175   Open ▸ above).
  2. The approach to the PVA and the metrics used to summarise the PVA outputs are as described for the Proposed Development alone (see Project Alone: Population-Level Impacts section above).
Table 5.176:
Projected 35-year population sizes and associated PVA metrics for the East Caithness Cliffs SPA razorbill population under different impact scenarios for the Proposed Development in-combination with the other UK North Sea wind farms.

Table 5.176: Projected 35-year population sizes and associated PVA metrics for the East Caithness Cliffs SPA razorbill population under different impact scenarios for the Proposed Development in-combination with the other UK North Sea wind farms.

  1. For the Proposed Development in-combination with the other UK North Sea wind farms, the CPS value for the Developer Approach indicates that the SPA population size would be reduced by approximately 4.6% relative to that in the absence of any wind farm effects ( Table 5.176   Open ▸ ). The reduction in annual population growth rate (relative to that predicted under baseline conditions) remains small, whilst the centile value continues to indicate a considerable overlap in the distributions of the predicted impacted and un-impacted population sizes and, hence, a high likelihood of the impacted population being of a similar size to the un-impacted population after 35 years.
  2. The metrics associated with the Scoping Approach for the Proposed Development in-combination with the other UK North Sea wind farms inevitably suggest greater levels of effect. However, at the lower range of effects (i.e. Scoping Approach A) they continue to indicate a relatively small effect and a reasonable likelihood of the impacted population being of a similar size to the un-impacted population after 35 years. At the upper range of effects (i.e. Scoping Approach B), the CPS value indicates that the SPA population size would be reduced by approximately 20% relative to that in the absence of any wind farm effects ( Table 5.176   Open ▸ ), whilst the reduction in annual population growth rate (relative to that predicted under baseline conditions) is estimated as 0.6%. The centile value of 29.4 suggests a reasonably high likelihood of the impacted population being smaller than the un-impacted population after 35 years.
In-Combination: Conclusion
  1. On the basis of the Developer Approach, it is considered that the potential effects from the Proposed Development in-combination with the other UK North Sea wind farms would not result in an adverse effect on the East Caithness Cliffs SPA razorbill population. The population-level impacts predicted to arise from these in-combination effects represent a small increase to those predicted due to the Proposed Development alone. As such, it is considered that the conclusions reached in relation to the Proposed Development alone are also valid for the in-combination scenarios.
  2. In terms of the Scoping Approach, it is considered that the lower range of the predicted impacts (i.e. Scoping Approach A) would not represent an adverse effect on the SPA population but that it is possible the upper range would (i.e. Scoping Approach B). Consequently, it is concluded that the effects of the Proposed Development in-combination with the other UK North Sea wind farms could result in an adverse effect on the East Caithness Cliffs SPA razorbill population.

Assessment for the Breeding Seabird Assemblage

  1. The breeding seabird assemblage for the East Caithness Cliffs SPA is a qualifying feature on the basis of the SPA supporting in excess of 20,000 individual seabirds (with the citation also noting that the SPA regularly supports 300,000 seabirds). Kittiwake and razorbill comprise two of the eight species identified in the citation as having populations which are considered to be of European or national importance and which contribute to the East Caithness Cliffs SPA breeding seabird assemblage (no LSE was determined for the other six species in relation to the Proposed Development (HRA Stage One Screening Report; SSE Renewables, 2021b).
  2. Potential impacts of the Proposed Development in-combination with other UK North Sea wind farms on the breeding seabird assemblage for the SPA could arise via effects on the individual species within the assemblage feature. For the Developer Approach, the assessments undertaken above identify the potential for adverse effects only on the SPA kittiwake population in relation to the in-combination scenario. For the Scoping Approach, the assessments undertaken above identify the potential for adverse effects on the SPA kittiwake and razorbill populations in relation the in-combination scenario.
  3. For the in-combination scenario as determined by the Developer Approach, the potential for adverse effects is identified only in relation to the SPA kittiwake population., Given the range of species present within the SPA seabird assemblage and their relative abundances, it is considered that the potential adverse effect on the SPA kittiwake population would not be sufficient to result in a subsequent adverse effect on the seabird assemblage.
  4. For the in-combination scenario as determined by Scoping Approach, it is also the case that the predicted impacts on the SPA kittiwake are not considered likely to lead to a risk of this population being lost from the breeding seabird assemblage at the East Caithness Cliffs SPA. However, it is considered conceivable that the combined predicted in-combination impacts on the SPA kittiwake and razorbill populations are such as to represent a risk of reducing the total number of individual seabirds present in the assemblage to a level that could represent an adverse effect on this qualifying feature. This conclusion should be considered within the context of the high levels of precaution incorporated within the assessment for Scoping Approach (volume 3, appendix 11.3 and volume 3, appendix, 11.4, annex G of the Offshore EIA Report).
  5. Given the above, it is concluded that there is the potential for an adverse effect on the East Caithness Cliffs SPA breeding seabird assemblage in relation to the Proposed Development in-combination with other UK North Sea wind farms, as determined by Scoping Approach. No potential for adverse effects on the SPA breeding seabird assemblage is identified in relation to the Proposed Development alone (irrespective of whether determined by the Developer or Scoping Approaches) or in relation to the Proposed Development in-combination with other UK North Sea wind farms, as determined by the Developer Approach.

Site Conclusion

Developer Approach
  1. It is concluded that the possibility of adverse effects cannot be discounted for the East Caithness Cliffs SPA population of breeding kittiwake. The potential for adverse effects arises from the Proposed Development in-combination with the other UK North Sea wind farms. The predicted impacts on the SPA kittiwake population are not considered to be sufficient to lead to a potential adverse effect on the breeding seabird assemblage feature.
  2. Consequently, it is concluded that an AEoI in respect of the kittiwake feature of the East Caithness Cliffs SPA cannot be excluded due to effects of the Proposed Development in-combination with other plans and projects. However, the effects from the Proposed Development would not result in an adverse effect on the razorbill population.
Scoping Approach
  1. It is concluded that the possibility of adverse effects cannot be discounted for the East Caithness Cliffs SPA populations of breeding kittiwake and razorbill, as well as the breeding seabird assemblage qualifying feature (due to the impacts on kittiwake and razorbill components only). For the kittiwake and razorbill populations, and the breeding seabird assemblage feature, the potential for adverse effects is in relation to the effects of the Proposed Development in-combination with other UK North Sea wind farms.
  2. Consequently, it is concluded that an AEoI in respect of the East Caithness Cliffs SPA cannot be excluded due to effects of the Proposed Development in-combination with other plans and projects.

5.7.8.    Flamborough and Filey Coast SPA

European site information and conservation objectives

  1. The coastal section of the Flamborough and Filey Coast SPA covers a slender strip of cliffs and hinterland along the coastline of the counties of North Yorkshire and the East Riding of Yorkshire, located approximately 215 km from the Proposed Development. The SPA is in two sections: the southern section extends north from South Landing around Flamborough Head to Speeton; the northern section covers the peninsula of Filey Brigg before extending northwest to Cunstone Nab. The seaward boundary extends 2 km into the marine environment throughout the two sections of the site. Flamborough Head and Bempton Cliffs was classified as an SPA in 1993, with the site extended and renamed as the Flamborough and Filey Coast SPA in 2018.
  2. The site qualifies under Article 4.2 by regularly supporting four migratory seabird species and in excess of 20,000 breeding seabirds, including five named component species (Table 5.177). The potential for LSE has been identified in relation to four of these nine species (Table 5.177), with the effect pathways associated with LSE for each of these detailed in Table 3.1 and set out in the assessment below.
  3. The conservation objectives of this SPA (as determined through Natural England Access to Evidence) are to:

Ensure that the integrity of the site is maintained or restored as appropriate, and ensure that the site contributes to achieving the aims of the Wild Birds Directive, by maintaining or restoring:

  • The extent and distribution of the habitats of the qualifying features
  • The structure and function of the habitats of the qualifying features
  • The supporting processes on which the habitats of the qualifying features rely
  • The populations of each of the qualifying features
  • The distribution of qualifying features within the site
    1. Further information on this European site, including the SACOs, is presented in appendix 3A.
Table 5.177:
Details of the Qualifying Features of the Flamborough and Filey Coast SPA

Table 5.177: Details of the Qualifying Features of the Flamborough and Filey Coast SPA

*Named components of the assemblage only.

 

Assessment for the gannet population

  1. The Flamborough and Filey Coast SPA gannet population is currently estimated to number 26,784 individuals, based upon the most recently available count data from 2017 (Offshore EIA Report, volume 3, appendix 11.5). This is substantially higher than the citation level of 16,938 individuals (Table 5.177). As with the Forth Islands SPA gannet population (and most gannet colonies elsewhere in Britain and Ireland – Mitchell et al. 2004, Murray et al. 2015), the Flamborough and Filey Coast SPA population has shown a marked and consistent increase in numbers with the annual population growth rate averaging approximately 11% since the colony establishment in the late 1930s (Natural England 2020). The population was estimated as fewer than 1,500 individuals in the mid-1980s, with numbers increasing to approximately 7,000 individuals by 2005 and 22,000 individuals by 2012, since when there is some indication of a possible (and slight) reduction in the rate of growth to give the 2017 estimate of almost 27,000 individuals (SMP 2022).
The potential for impacts on the gannet population
  1. The Proposed Development and two kilometre buffer around the Proposed Development array area7 do not overlap with the Flamborough and Filey Coast SPA, so that potential impacts on its gannet population will only occur as a result of individuals from the colony occurring in the area (or vicinity) of the Proposed Development. Consequently, the main focus of the assessment for this qualifying feature is concerned with the Conservation Objective of maintaining or restoring the populations of each qualifying feature, because the other conservation objectives either apply to the site itself, and not to areas beyond the boundary, or are encompassed by the assessment of this Conservation Objective (as for maintaining or restoring the structure and function of the habitats of the qualifying features, because habitat structure and function would only be considered significant if it caused an adverse effect on the maintenance or restoration of the population of the qualifying features). In terms of the SACOs, this focus is most closely reflected in the ‘breeding population: abundance’ attribute which has the target of maintaining the abundance of the breeding population of this feature above the citation level, whilst avoiding deterioration from its current level. Clearly, other attributes (e.g. connectivity with supporting habitats) are also relevant but, as for the conservation objectives above, their significance is linked to whether they prevent achievement of the attribute concerned with maintaining the abundance of the breeding population.
  2. From published information on gannet foraging ranges (Woodward et al. 2019) it is feasible that during the breeding season birds from this SPA population could occur within the area of the Proposed Development and of the two km buffer around the Proposed Development array area (because the Proposed Development is within the mean maximum foraging range plus 1 SD of gannet from the Flamborough and Filey Coast SPA). However, tracking data for gannet from the SPA provide no evidence that their breeding season foraging ranges encroach on waters close to the Proposed Development, whilst analyses of gannet tracking data from multiple colonies in Britain and Ireland suggest that the breeding season foraging ranges of birds from different colonies tend to be mutually exclusive, with the Proposed Development encompassed by the foraging ranges of birds from the Forth islands SPA population (Langston et al. 2013, Wakefield et al. 2013). The apportioning calculations estimate that 1.3% of the gannets occurring on the Proposed Development array area during the breeding season derive from the Flamborough and Filey Coast SPA colony (Offshore EIA Report, volume 3, appendix 11.5). The breeding period for gannet is defined as mid-March to September, following the NatureScot (2020) guidance.
  3. Gannets from the Flamborough and Filey Coast SPA move south in autumn to winter in more southern waters, returning north in the spring (Furness 2015), so that the non-breeding season is divided into autumn and spring passage periods (defined as October to November and December to mid-March, respectively, on the basis of applying the BDMPS defined periods within the context of the overall non-breeding period defined by NatureScot – Furness 2015, NatureScot 2020, Offshore EIA Report, volume 3, appendix 11.5). Given the above, the Proposed Development may have potential effects on the Flamborough and Filey Coast SPA gannet population during breeding and non-breeding periods.
Project alone: construction and decommissioning
Disturbance
  1. Direct disturbance to gannets during the construction phase may arise within the Proposed Development array area (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 wind turbine foundations and other infrastructure, whilst there will also be increased vessel activity along the Proposed Development export cable corridor due to the cable laying activities. The levels of such activities that could arise are outlined in Table 4.1, with these activities occurring during construction campaigns within a construction period of at most eight years duration.
  2. A total of up to 11,482 vessel round trips may occur over the construction phase, whilst it is estimated that a maximum of 134 vessels could occur within the area of the Proposed Development at any one time (Table 4.1). However, this is within the context of high baseline levels of vessel traffic within this area (e.g. surveys recorded an average of 14 vessels per day within a 10 nm buffer around the Proposed Development over a 14-day period in August 2022, whilst also showing an average of three to four vessels intersecting the Proposed Development array area per day over summer - Offshore EIA Report, volume 2, chapter 13).
  3. When using the marine environment (and not at the breeding colony), gannets are considered to have a relatively low sensitivity to such sources of direct disturbance. Thus, reviews of the sensitivity of different seabird species to disturbance from vessels and helicopter traffic assign gannet as ‘2’ on a five-scale ranking system, where 1 indicates hardly any or limited escape/avoidance behaviour and very short flight distance when approached and 5 indicates strong escape/avoidance behaviour and a large response distance (Garthe and Hüppop 2004, Furness et al. 2013).
  4. The total area to be affected by such disturbance over the full eight years of the construction phase also represents a small proportion of the total area of marine habitat available to gannets from the Flamborough and Filey Coast SPA. Thus, the Proposed Development array area encompasses 1,010 km2, whilst the Proposed Development export cable encompasses 168 km2. Together these areas represent less than 0.5% of the total breeding season foraging area that is potentially available to the SPA gannet population, as defined by the generic measure of the species’ mean maximum breeding season foraging range plus 1 SD (i.e. 309.2±194.2 km - Woodward et al. 2019) and assuming that this range is represented by a semicircle to the seaward side of the colony. Similarly, the Proposed Development array area and export cable corridor represent less than 1% of the breeding season foraging area if considering the mean maximum foraging range only. Furthermore, as detailed above, evidence from tracking data suggests that the waters encompassed by the Proposed Development are rarely used by gannets from the Flamborough and Filey Coast SPA during the breeding season (Langston et al. 2013, Wakefield et al. 2013).
  5. During the autumn and spring passage periods, the potential for effects of construction-related disturbance is limited to SPA gannets are essentially transiting through the waters within which the Proposed Development is located.
  6. In addition, it is important to consider that the construction activities will not occur simultaneously across the entirety of the Proposed Development array area or the Proposed Development export cable corridor but, rather, will be carried out in different areas at different times. Thus, the activities will be concentrated within discrete (often small) parts of these wider areas, and within such areas they will not extend over the full duration of the construction phase, so further reducing the potential to which birds may be subject to disturbance effects. For example, cable laying for the Proposed Development export cable will occur over a total of two years, whilst within the Proposed Development array area it is likely that construction activities would be confined largely to discrete areas at any one time.
  7. 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.
  8. Given the low sensitivity of gannet to disturbance effects, the low likelihood of birds from this SPA population occurring within the waters encompassed by the Proposed Development during the breeding season, 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 to lead to an adverse effect on the Flamborough and Filey Coast SPA gannet population.
Displacement
  1. As detailed above, gannet is considered to have a low sensitivity to disturbance, whilst potential effects of disturbance during the construction and decommissioning phases will only extend across a small part of the wider foraging areas potentially used by the Flamborough and Filey Coast SPA gannet population and be limited to, at most, an eight year period during construction (and a likely similar or shorter period during decommissioning). Furthermore, as detailed above, potential effects of disturbance will not occur simultaneously across the entirety of the Proposed Development array area or Proposed Development export cable corridor but, rather, will be carried out in different areas at different times. Thus, at any given time the potential for disturbance effects that could lead to displacement of gannet from this SPA will be limited to relatively small areas, with the potential effects also being of a temporary nature.
  2. Therefore, based upon the above, it is considered that there is relatively little potential for the Flamborough and Filey Coast SPA gannet population to be affected by displacement during the construction or decommissioning phases, with any such effects only extending across relatively small areas and tending to be temporary in nature. Consequently, it is considered that there is no potential for construction or decommissioning related displacement to lead to an adverse effect on the Flamborough and Filey Coast SPA gannet population.
Changes to prey availability
  1. Gannets predominantly prey upon fish including herring, mackerel, sprat and sandeel, as well as fishery discards (del Hoyo et al., 1996). Indirect effects on gannets may arise as a result of changes in the availability, distribution, or abundance of these species during the construction and decommissioning phases of the Proposed Development. Reduction or disruption to prey availability may cause displacement from foraging grounds or reduced energy intake, affecting survival rates or productivity in the Flamborough and Filey Coast SPA gannet population in the short-term.
  2. During construction there are a number of ways in which effects on gannet prey species could occur, which are as outlined in the section on Project Alone: Construction and Decommissioning – Changes to prey availability for the St Abb’s Head to Fast Castle SPA kittiwake population and in volume 2, chapter 9 of the Offshore EIA Report. However, the Proposed Development array area and export cable represent less than 0.5% of the total breeding season foraging area that is potentially available to the SPA gannet population, as defined by the species’ mean-maximum breeding season foraging range plus 1 SD (i.e. 309.2±194.2 km; Woodward et al., 2019) and assuming that this range is represented by a semicircle to the seaward side of the colony. Additionally, the evidence from tracking data, which suggests that gannets from the Flamborough and Filey Coast SPA will rarely use the waters encompassed by the Proposed Development during the breeding season, is relevant (Langston et al. 2013, Wakefield et al. 2013). The potential for any effects during the autumn and spring passage periods is considered to be low because birds disperse widely through UK waters to their wintering grounds (Kubetski et al., 2009; Furness 2015).
  3. 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 gannet prey species (Birchenough and Degrae 2020; 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 scour and 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 the area over which breeding and non-breeding gannets forage.
  4. Given their wide-ranging foraging behaviour and degree of plasticity in diet (del Hoyo et al., 1996), together with any effects being intermittent, spatially-restricted and temporary in nature, 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 Flamborough and Filey Coast SPA gannet population. This conclusion is consistent with the outcome of the EIA which concluded that effects from changes in prey availability on gannets during construction and decommissioning were not significant in EIA terms (volume 2, chapter 11 of the Offshore EIA Report).
Project alone: operation and maintenance
Disturbance
  1. Vessel use within the Proposed Development array area and export cable corridor during the operation and maintenance phase may lead to direct disturbance of gannets. The maximum design scenario is for up to 3,393 vessel round trips per year over the operational lifetime of the project (Table 4.1).
  2. Based on information presented in the Offshore EIA Report, volume 2, chapter 13, baseline levels of vessel traffic in the Offshore Ornithology study area are relatively high (see section on Project Alone: Operation and Maintenance – Disturbance for the St Abb’s Head to Fast Castle SPA kittiwake population). In the context of the baseline levels of vessel traffic across the Offshore Ornithology study area, the increase during the operation and maintenance phase is considered to be relatively small. Vessel movements will be within the Proposed Development array area and export cable corridor and will follow existing shipping routes to/from ports. In addition, Project Codes of Conduct included as a part of the NSVMP (Offshore EIA Report, volume 4, appendix 25) will be issued to all project vessel operators to avoid sudden changes in course or speed which will minimise the potential for disturbance.
  3. The size and noise outputs from vessels during the operation and maintenance phase will be similar to those used in the construction phase. However, the number of vessel return trips per year and their frequency will be much lower than during the construction phase. In addition, activities during the operation and maintenance phase will not occur simultaneously across the entirety of the Proposed Development array area and export cable corridor but intermittently within discrete (often small) parts of these wider areas.
  4. Given the low sensitivity of gannet to disturbance effects at sea (Garthe and Hüppop 2004; Furness et al., 2013), the relatively small areas relative to the species’ foraging range that will be subject intermittently to potentially disturbing activities (Woodward et al., 2019), and the fact that these potential effects will be reduced compared to the construction and decommissioning phases, it is considered that there is no potential for disturbance during operation and maintenance to lead to an adverse effect on the Flamborough and Filey Coast SPA gannet population. This conclusion is consistent with the outcome of the EIA which ‘screened’ out gannet as a species for which detailed consideration of the effects of construction disturbance was required (volume 2, chapter 11 of the Offshore EIA Report).
Displacement/barrier effects
  1. As outlined above, displacement effects on the Flamborough and Filey Coast SPA gannet population are estimated using the SNCB matrix approach, as applied to the Proposed Development array and two kilometre buffer (SNCBs 2022, Offshore EIA Report, volume 3, appendix 11.4). Thus, throughout this section, mortality from displacement is assumed to refer to that which results from both displacement and barrier effects. The approach used to derive predicted levels of mortality is as described in the section on Project Alone: Operation and Maintenance – Displacement/Barrier Effects for the St Abb’s Head to Fast Castle SPA kittiwake population above (and in the Offshore EIA Report, volume 3, appendix 11.4).
  2. On the basis of the advice provided in the Scoping Opinion (volume 3, appendix 6.2 of the Offshore EIA Report), displacement effects on gannet are estimated for the breeding period and each of the autumn and spring passage periods. The displacement and associated mortality rates advised in the Scoping Opinion (subsequently termed the Scoping Approach) for gannet are:
  • Breeding period: 70% displacement with lower and upper mortality rates of 1% and 3%.
  • Non-breeding periods: 70% displacement with lower and upper mortality rates of 1% and 3%.
    1. As with other species for which displacement effects are assessed (see above), the approach to estimating gannet displacement effects advocated by the Scoping Opinion was considered overly precautionary. For gannet, this was specifically concerned with the upper range of the proposed mortality rates, and the evidence available to support this (volume 3, appendix 11.4, annex G of the Offshore EIA Report). Furthermore, the mortality rates advocated by the Scoping Opinion represented a marked change from the assumptions applied in assessments for other recent Scottish offshore wind farms (Marine Scotland 2017a,b,c) with no clear evidence apparently being available to justify such a change. Thus, based on a consideration of the available evidence for gannet displacement, the extent of the species’ ranging behaviour, previous precedent and a need to incorporate precaution within the assessment, an alternative Developer Approach to estimating displacement effects was determined (volume 3, appendix 11.4, annex G of the Offshore EIA Report). The rates adopted by the Developer Approach (for both displacement and consequent mortality) are as for the lower range of the Scoping Approach (i.e. 70% displacement and 1% mortality in for all seasonal periods).
    2. Estimates of gannet mortality were produced using the SNCB matrix on the basis of both the Scoping Approach and the Developer Approach (Offshore EIA Report, volume 3, appendix 11.4), with these estimates then apportioned to the Flamborough and Filey Coast SPA gannet population during the breeding and non-breeding periods according to the NatureScot (2018) approach and the BDMPS approach (Furness 2015), respectively (Offshore EIA Report, volume 3, appendix 11.5, Table 5.178). The resulting mortality estimates for the breeding period were apportioned to age classes on the basis of the plumage characteristics of gannets recorded during the breeding period in the baseline surveys (Offshore EIA Report, volume 3, appendix 11.1), whilst for the non-breeding periods age classes were apportioned according to the stable age distributions of the population model used in Furness (2015). Based on advice provided by NatureScot and Marine Scotland Science following Roadmap Meeting 4 (G. Holland, email 26/01/2022), it was also assumed that 10% of the breeding adults in the SPA population miss breeding in any given year (i.e. sabbatical birds) so that the number of estimated adult deaths during the breeding season was adjusted accordingly.

 

Table 5.178:
The Mean Peak Abundance Estimates of Gannet in the Proposed Development Array Area and 2 km Buffer for Each Seasonal Period, Together with the Proportion of Birds Estimated to Belong to the Breeding Adult Age Class and to be from the Flamborough and Filey Coast SPA Population in Each Period. The Proportion of Adults Assumed to be Sabbaticals During the Breeding Season is also Presented

Table 5.178: The Mean Peak Abundance Estimates of Gannet in the Proposed Development Array Area and 2 km Buffer for Each Seasonal Period, Together with the Proportion of Birds Estimated to Belong to the Breeding Adult Age Class and to be from the Flamborough and Filey Coast SPA Population in Each Period. The Proportion of Adults Assumed to be Sabbaticals During the Breeding Season is also Presented

 

  1. Based upon the estimates and assumptions detailed above, the potential annual mortality amongst the SPA gannet population as a result of displacement is estimated as a single bird (adults and immatures combined) based on the Developer Approach and the lower mortality rates for the Scoping Approach (i.e. Scoping Approach A) and as two adult and one immature birds based upon the higher mortality rates for the Scoping Approach (i.e. Scoping Approach B) (Table 5.179). Approximately 40% of the predicted displacement effects are attributable to the breeding season for both the Developer and Scoping Approaches (Table 5.179).

 

Table 5.179:
Estimated Potential Annual Mortality of Flamborough and Filey Coast SPA Gannets as a result of Displacement from the Proposed Development Array Area and 2 km buffer as Determined by the Scoping Approach and Developer Approach

Table 5.179: Estimated Potential Annual Mortality of Flamborough and Filey Coast SPA Gannets as a result of Displacement from the Proposed Development Array Area and 2 km buffer as Determined by the Scoping Approach and Developer Approach

 

  1. The additional annual mortality of adult gannets from the Flamborough and Filey Coast SPA population predicted due to displacement as a result of the Proposed Development array represents less than 0.01% of the current adult breeding population at this colony (i.e. 26,784 individuals – Table 3.3 in the Offshore EIA Report, volume 3, appendix 11.5) as determined by the Developer Approach and the Scoping Approach. In terms of percentage increases in the baseline annual adult mortality of the population (which is based on applying a mortality rate of 0.046 – see Table 2.7 in the Offshore EIA Report, volume 3, appendix 11.6), the estimates of adult mortality equate to an increase of approximately 0.1% for the Developer Approach and of 0.1 – 0.2% for the lower and upper estimates from the Scoping Approach.
  2. These are very small levels of effect which would be highly unlikely to lead to any detectable population-level impacts. Consequently, it is considered that there is no potential for displacement and barrier effects from the Proposed Development alone during operation and maintenance to lead to an adverse effect on the Flamborough and Filey Coast SPA gannet population.
Collision risk
  1. Predictions of the number of gannets at risk from collisions due to the Proposed Development were calculated using the deterministic version of the SOSS offshore collision risk model (Band 2012, Offshore EIA Report, volume 3, appendix 11.3). Following the Scoping Opinion (volume 3, appendix 6.2 of the Offshore EIA Report), the assessment is based on option 2 of the CRM, which uses the generic flight height data from Johnston et al. (2014a,b) and assumes a uniform distribution of flight heights across the rotor swept zone (as opposed to using the modelled flight height distribution) (Band 2012). An avoidance rate of 98.9% was applied to these CRM outputs, as recommended for gannet (SNCBs 2014) and as advised by the Scoping Opinion.
  2. As outlined for St Abb’s Head to Fast Castle SPA kittiwake population above, guidance on the use of the CRM suggests that model predictions should be based upon the mean monthly densities of flying birds estimated within the array area (Band 2012)8 and, to the best of the Applicant’s knowledge, this approach has been applied in all recent UK offshore wind farm assessments. Despite this, the Scoping Opinion advised that the CRMs for the Proposed Development should use the maximum monthly densities of flying birds within the array area. Further details on this are provided above in the Project Alone: Operation and Maintenance - Collision Risk section for St Abb’s Head to Fast Castle SPA kittiwakes (and in volume 3, appendix 11.3 of the Offshore EIA Report) but, as a result of this overly precautionary approach (which does not follow previous precedent), the CRMs for gannet were undertaken following:
  • The Scoping Approach of using the maximum monthly densities, and
  • The Developer Approach of using the mean monthly densities.
    1. In addition to the above, collision estimates for gannets were also calculated using option 2 of the stochastic version of the CRM (McGregor et al. 2018) with avoidance rates as derived from the bird collision-avoidance study undertaken at the Thanet offshore wind farm (Bowgen and Cook 2018). These additional collision estimates are not used as the basis of the assessments on the SPA gannet populations but, instead, are used solely to illustrate the consequences of applying these alternative avoidance rates which have been derived from studies at an actual offshore wind farm. Details of these additional CRMs are provided in annex C of the Offshore EIA Report, volume 3, appendix 11.3.
    2. As for the predicted displacement effects, gannet collision estimates are calculated for the breeding and non-breeding periods, with the latter separated into autumn and spring passage periods (Offshore EIA Report, volume 3, appendix 11.5). Estimates were apportioned to the gannet SPA population during the breeding and non-breeding periods according to the NatureScot (2018) approach and the BDMPS approach (Furness 2015), respectively (Offshore EIA Report, volume 3, appendix 11.5, Table 5.178). The age class proportions and assumptions on sabbatical rates are also as detailed above in relation to displacement effects (Table 5.178).
    3. Based upon option 2 of the deterministic CRM with a 98.9% avoidance rate applied, and in conjunction with the estimates and assumptions detailed above, the annual collision mortality of gannets from the Flamborough and Filey Coast SPA is predicted to be approximately three birds (adults and immatures combined) as determined by the Scoping Approach, and approximately two birds (adults and immatures combined) as determined by the Developer Approach (Table 5.180). In contrast to displacement, the majority of this mortality (i.e. 57 – 69%) is predicted to occur during the breeding season.

 

Table 5.180:
Predicted collision Effects from the Proposed Development on the Flamborough and Filey Coast SPA Gannet Population, as Determined by the Scoping Approach and Developer Approach. Estimates are for the Maximum Design Scenario and are Based on Option 2 of the Deterministic CRM Using a 98.9% Avoidance Rate (see text)

Table 5.180: Predicted collision Effects from the Proposed Development on the Flamborough and Filey Coast SPA Gannet Population, as Determined by the Scoping Approach and Developer Approach. Estimates are for the Maximum Design Scenario and are Based on Option 2 of the Deterministic CRM Using a 98.9% Avoidance Rate (see text)

 

  1. The additional annual mortality of adult gannets from the Flamborough and Filey Coast SPA population predicted due to collisions with wind turbines in the Proposed Development array represents less than 0.01% of the number of adults currently estimated to breed at this colony (i.e. 26,784 individuals – Table 3.3 in the Offshore EIA Report, volume 3, appendix 11.5) as determined by the Developer Approach and the Scoping Approach. In terms of percentage increases in the baseline annual adult mortality of the population (which is based on applying a mortality rate of 0.046 – see Table 2.7 in the Offshore EIA Report, volume 3, appendix 11.6), the predicted adult collision mortality equates to increases of approximately 0.2% for both the Developer and Scoping Approaches.
  2. The collision estimates produced using option 2 of the stochastic CRM with the Bowgen and Cook (2018) avoidance rates applied are 54% lower than those presented in Table 5.180 (for both the Scoping and Developer Approaches).
  3. The levels of effect detailed in Table 5.180 are very small and would be highly unlikely to lead to any detectable population-level impacts. Consequently, it is considered that there is no potential for collision mortality associated with the Proposed Development alone during operation and maintenance to lead to an adverse effect on the Flamborough and Filey Coast SPA gannet population.
Changes to Prey Availability
  1. Potential impacts on key prey species for gannets breeding at the Flamborough and Filey Coast SPA during the operation and maintenance phase have been assessed in volume 2, chapter 9 of the Offshore EIA Report using the appropriate maximum design scenarios for these receptors. Reduction or disruption to prey availability through temporary and long-term subtidal habitat loss/disturbance, increased SSC and deposition, EMF from subsea electrical cabling, and colonisation of subsea structures could affect gannet survival and productivity in the Flamborough and Filey Coast SPA population.
  2. Artificial structures introduced to the marine environment provide hard substrate for settlement of various organisms, which can increase local food availability for higher trophic levels. Whilst there is mounting evidence of potential benefits of artificial structures in marine environment (Birchenough and Degrae 2020), the statistical significance of such benefits and details about trophic interactions remain largely unknown (Scott, 2022).
  3. Given their wide-ranging foraging behaviour and degree of plasticity in diet (del Hoyo et al., 1996), together with any effects being largely intermittent across a relatively small spatial extent, 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 Flamborough and Filey Coast SPA gannet population. This conclusion is consistent with the outcome of the EIA which concluded that effects from changes in prey availability on gannets during operation and maintenance were not significant in EIA terms (volume 2, chapter 11 of the Offshore EIA Report).
Combined effects of displacement/barrier effects and collision risk
  1. As determined above, none of the effect pathways identified as relevant to the Stage Two assessment are considered to have the potential to lead to an adverse effect on the Flamborough and Filey Coast SPA gannet population when considered on their own. However, both displacement (inclusive of barrier effects) and collision risk during the operation and maintenance phase are identified as having the potential to result in (small levels of) additional mortality. Therefore, it is relevant to determine the potential effects of the combined mortality from these two effect pathways on the Flamborough and Filey Coast SPA gannet population.
  2. Based upon the Developer Approach the potential combined mortality from displacement and collision risk equates to a total of 2.7 adult and 0.6 immature birds, whilst for the Scoping Approach the potential combined mortality ranges from 3.2 – 4.6 adult and 0.7 – 1.2 immature birds (Tables 5.179 and 5.180). Considering the adult age class, these levels of additional mortality represent 0.01% of the number of adults currently estimated to breed at this colony (i.e. 26,784 individuals – Table 3.3 in the Offshore EIA Report, volume 3, appendix 11.5) as determined by the Developer Approach and between 0.011 – 0.017% of this population as determined by the lower and upper estimates from the Scoping Approach. In terms of percentage increases in the baseline annual adult mortality of the population (which is based on applying a mortality rate of 0.046 – see Table 2.7 in the Offshore EIA Report, volume 3, appendix 11.6), the predicted combined adult mortality equates to increases of 0.2% for the Developer Approach and of 0.3 – 0.4% for lower and upper estimates from the Scoping Approach.
  3. These are very small levels of effect which would be highly unlikely to lead to any detectable population-level impacts. Consequently, it is considered that there is no potential for the predicted combined mortality resulting from displacement (inclusive of barrier effects) and collisions from the Proposed Development alone during operation and maintenance to lead to an adverse effect on the Flamborough and Filey Coast SPA gannet population.
Project alone: conclusion
  1. For both the Developer and Scoping Approaches, the potential effects from the Proposed Development alone on the Flamborough and Filey Coast SPA gannet population are predicted to be small and would be highly unlikely to lead to any detectable population-level impacts. 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
  1. As detailed above, any effects from the Proposed Development alone on the Flamborough and Filey Coast SPA gannet population during construction and decommissioning and resulting from disturbance and changes to prey availability during operation and maintenance will be small and highly localised. As such, there is considered to be no potential for these effect pathways to add to impacts at the population-level that might result from the effects due to other plans and projects.
  2. Therefore, the potential for effects of the Proposed Development to act on the Flamborough and Filey Coast SPA gannet population in-combination with other plans and projects is limited to the displacement (inclusive of barrier effects) and collision risk effect pathways during operation and maintenance. The following sections consider these potential effects for the Proposed Development in-combination with the other UK North Sea wind farms.
Displacement/barrier effects – operation and maintenance
  1. To estimate the breeding season displacement mortality for the Flamborough and Filey Coast SPA gannet population due to the other UK North Sea wind farms, the apportioned breeding season gannet numbers associated with other offshore wind farms that are in planning, consented, under construction or in operation were first extracted from the cumulative totals collated for the East Anglia TWO and East Anglia ONE North submissions (MacArthur Green and Royal HaskoningDHV 2021, see annex E of volume 3, appendix 11.6 of the Offshore EIA Report for more details). No information could be determined on the age distribution of the birds comprising these totals and it was assumed that 97% were breeding adults from the SPA, on the basis that this is the average percentage of adults recorded in the breeding season during baseline surveys of the three existing Forth and Tay wind farms (ICOL 2018). This is likely to be a highly precautionary assumption because most of the plans and projects contributing to these cumulative totals are located at considerably greater distances from the Flamborough and Filey Coast SPA than are the existing Forth and Tay wind farms from the Forth Islands SPA (and hence it is likely that they would include a higher proportion of non-breeding birds). Displacement mortality estimates for the breeding season were then calculated by applying the displacement and mortality rates appropriate to the Scoping and Developer Approaches to the apportioned cumulative total number of adults and immatures (Table 5.179).
  2. For the non-breeding periods, gannet numbers for each of the relevant seasonal periods were also extracted from the cumulative totals collated for the East Anglia TWO and East Anglia ONE North submissions (MacArthur Green and Royal HaskoningDHV 2021, see Offshore EIA Report annex E of volume 3, appendix 11.6 for more details). The cumulative numbers for each of the autumn and spring passage periods were apportioned to the Flamborough and Filey Coast SPA gannet population according to the BDMPS approach as detailed in the assessment for the East Anglia THREE wind farm (MacArthur Green 2015, Royal HaskoningDHV et al. 2015). The subsequent displacement mortality was calculated according to the displacement and mortality rates appropriate to each of the Scoping and Developer Approaches (Table 5.179).
  3. The predicted displacement mortality derived for the other UK North Sea wind farms was combined with that from the Proposed Development to give the in-combination estimates according to both the Scoping and Developer Approaches (Table 5.181).

 

Table 5.181:
Estimated Annual Mortality of Flamborough and Filey Coast SPA Gannets as a Result of Displacement from the Proposed Development Array Area and 2 km Buffer as Determined by the Scoping Approach and Developer Approach, In-Combination with other UK North Sea Wind Farms

Table 5.181: Estimated Annual Mortality of Flamborough and Filey Coast SPA Gannets as a Result of Displacement from the Proposed Development Array Area and 2 km Buffer as Determined by the Scoping Approach and Developer Approach, In-Combination with other UK North Sea Wind Farms

 

  1. The incorporation of the potential mortality associated with the other plans and projects results in substantive increases in the mortality predicted due to displacement effects relative to that from the Proposed Development alone. Thus, the potential mortality of adult birds from the Proposed Development in-combination with the other UK North Sea wind farms is almost 100 times greater than for the Proposed Development alone, for both the Developer and Scoping Approaches (compare Table 5.181 with Table 5.179). Increases in the potential mortality amongst the immature age class (which remains low compared to that of adults) relative to that from the Proposed Development alone are less marked but nonetheless substantive, being approximately twentyfold. The vast majority of the mortality (i.e. 83%) is attributable to the breeding season (Table 5.181).
  2. For the Proposed Development in-combination with the other UK North Sea wind farms, the additional annual mortality of adult gannets from the SPA population predicted due to displacement represents 0.25% of the current adult breeding population at this colony (i.e. 26,784 individuals – Table 3.3 in the Offshore EIA Report, volume 3, appendix 11.5) as determined by the Developer Approach, and between approximately 0.25 – 0.76% of this population as determined by the lower and upper estimates from the Scoping Approach. In terms of percentage increases in the baseline annual adult mortality of the population (which is based on applying a mortality rate of 0.046 – see Table 2.7 in Offshore EIA Report, volume 3, appendix 11.6), the estimates of adult displacement mortality equate to an increase of 5.5% for the Developer Approach and of 5.5 – 16.5% for the lower and upper estimates from the Scoping Approach.
  3. The potential levels of impact on the Flamborough and Filey Coast SPA gannet population resulting from the mortality predicted from displacement and barrier effects associated with the Proposed Development in-combination with the other UK North Sea wind farms during the operation and maintenance phase are considered in more detail below in the In- combination: Population-Level Impacts section. This presents the outputs from PVAs of the combined effects of predicted displacement and collision mortality on the SPA population.