Changes in Fish and Shellfish Communities Affecting Prey Availability
Tier 2
1627 There is potential for in-combination effects from changes in the prey resources available for harbour porpoise from the Southern North Sea SAC as a result of changes to the fish and shellfish community during the construction and decommissioning phases of the Proposed Development with activities associated with the following projects: Inch Cape Offshore Wind Farm, Neart na Gaoithe Offshore Wind Farm, Seagreen 1 Offshore Wind Farm, Seagreen 1A Project, Seagreen Eastern Link 1, Seagreen 1A Export Cable Corridor, Eastern Link 2 and Eyemouth disposal site.
1630 The impacts of construction and decommissioning will be highly localised and largely restricted to the boundaries of respective projects. Given that the temporal overlap in construction activities between projects will be small, there will only be a small area of temporary habitat loss happening at any one time. Harbour porpoise eat a variety of prey including gobies, sandeel, whiting, herring and sprat. Findings presented in paragraph 793 suggest that Firth of Forth and Tay area for this species is unlikely to represent important breeding or foraging habitat that would not be available elsewhere within the species home range over the North Sea. There may be, however, an energetic cost associated with increased travelling and due to harbour porpoise high metabolic rate, this species may be particularly vulnerable to this effect. However, harbour porpoises have a widespread distribution and individuals have been documented either switching to different prey species depending on the prey availability (Santos and Pierce, 2003) or moving relatively large distances on a daily basis (Nielsen et al., 2013). Based on findings of Benhemma-Le Gall et al. (2021) it can be anticipated that harbour porpoise can compensate for any resulting loss in energy intake by increasing foraging activities beyond impact zone. The availability of wider suitable habitat suggest that individuals may move to alternative foraging grounds without affecting the health of animals.
1631 Therefore, it can be concluded that there is no risk of an Adverse Effect on Integrity on the Southern North Sea SAC as a result of changes in fish and shellfish communities affecting prey availability during construction and decommissioning with respect to the Proposed Development acting in-combination with Tier 2 projects.
Tier 3
1632 There is potential for in-combination effects from changes in fish and shellfish communities affecting prey availability to harbour porpoise from Southern North Sea SAC during the construction and decommissioning phases of the Proposed Development with activities associated with the construction and operation of Cambois connection.
1633 The construction phase of Cambois connection may lead to in-combination temporary subtidal habitat loss/disturbance. The total in-combination temporary subtidal habitat loss/disturbance is 17,000,000 m2 (17.0 km2), however this number is highly conservative as the temporal overlap in construction activities between projects will be small and therefore there will only be a small area of temporary habitat loss happening at any one time. The majority of this disturbance will not spatially overlap with the Proposed Development and where the overlap exist with the Proposed Development array area (previously impacted during the construction of the Proposed Development), it is expected to be highly localised and so the potential for repeat disturbance is considered low and unlikely to lead to an increase in the magnitude than predicted for the Proposed Development alone. The installation of Cambois connection may also result in a total area of long-term subtidal habitat loss (e.g. from cable protection) of 306,000 m2.
1634 There is also a potential for in-combination effects associated with SSC and associated deposition. However, elevations in SSC during the construction phase will be of short duration, returning to background levels relatively quickly. SSC will not reach the concentrations required for an extended period for there to be any effect on fish and shellfish adult/larvae survival. Therefore, it is highly unlikely to have indirect impacts on harbour porpoise from Southern North Sea SAC via changes to prey species.
1635 Therefore, it can be concluded that there is no risk of an Adverse Effect on Integrity on the Southern North Sea SAC as a result of changes in fish and shellfish communities affecting prey availability during construction and decommissioning with respect to the Proposed Development acting in-combination with Tier 3 projects.
Assessment of in-combination effects during operation and maintenance
Changes in fish and shellfish communities affecting prey availability
Tier 2
1636 There is potential for in-combination effects from changes in prey resources to harbour porpoise from the Southern North Sea SAC during the operation and maintenance phase of the Proposed Development with activities associated with the following projects: Inch Cape Offshore Wind Farm, Neart na Gaoithe Offshore Wind Farm, Seagreen 1, Seagreen 1A Project, Seagreen 1A Export Cable, Eastern Link 1, Eastern Link 2, and Eyemouth disposal site.
1637 Operation and maintenance activities at respective projects considered in the Tier 2 in-combination assessment may lead to temporary subtidal habitat loss/disturbance of up to 32,276,397 m2. Additionally, the projects listed above will reach their decommissioning age during Proposed Development operation and maintenance phase. However, it is important to note that the maximum design scenario for habitat loss from the cumulative projects is precautionary, as operation and maintenance activities will occur intermittently throughout the lifetime of the Proposed Development and the temporal overlap with activities at other projects is unlikely. As described in paragraph 1011, only a small proportion of the maximum footprint of habitat loss/disturbance may be affected at any one time, with disturbed areas are starting to recover immediately after cessation of maintenance activities. Long-term subtidal habitat loss within the Proposed Development fish and shellfish ecology study area will occur during construction (i.e. through placement of infrastructure) although effects will extend throughout the operation and maintenance phase (see paragraph 1628). Areas within the Southern North Sea SAC provide good foraging habitat for harbour porpoise. Given that all operation and maintenance activities associated with the Proposed Development will take place outside the SAC, there will be no adverse effects on the site in-combination with other projects. The condition of supporting habitats and processes within site will not be affected/impaired and the availability of prey will be maintained.
1638 In-combination impacts could arise from EMFs due to the presence of subsea cabling during the operation and maintenance phases of the Proposed Development as well as Inch Cape Offshore Wind Farm, Neart na Gaoithe Offshore Wind Farm, Seagreen 1, Seagreen 1A Project, Seagreen 1A Export Cable, Eastern Link 1 and Eastern Link 2. A total length of up to 6,112 km of subsea cabling was estimated for all projects. The effect of EMF was predicted to be of local spatial extent Considering the above, adverse effects on harbour porpoise as a result of changes in prey availability due to EMF are unlikely.
1639 Artificial structures introduced into areas of predominantly soft sediments has the potential to alter community composition and biodiversity. There is a potential for in-combination effects arising from colonisation due to the presence of Inch Cape Offshore Wind Farm, Neart na Gaoithe Offshore Wind Farm, Seagreen 1, Seagreen 1A Project, Seagreen 1A Export Cable Corridor, Eastern Link 1 and Eastern Link 2 with a maximum scenario of up to 15,014,156 m2 of hard structures from wind turbines, OSP/Offshore convertor station platforms, meteorological masts, of cable protection, and cable crossings. It is anticipated that artificial structures will provide hard settlement opportunities and provide a valuable food source for fish. As discussed in paragraph 10211011 et seq, evidence increasingly suggests that foraging opportunities for marine mammals are increased around offshore wind farm structures. Therefore, presence of artificial structures may benefit harbour porpoise population in the long-term.
1640 Therefore, it can be concluded that there is no risk of an Adverse Effect on Integrity on the Southern North Sea SAC as a result of changes in fish and shellfish communities affecting prey availability during operation and maintenance with respect to the Proposed Development acting in-combination with Tier 2 projects.
Tier 3
1641 There is potential for in-combination effects from changes in fish and shellfish communities affecting prey availability to harbour porpoise from the Southern North Sea SAC during the operation and maintenance phase of the Proposed Development with activities associated with the operation of Cambois connection.
1642 In terms of temporary subtidal habitat loss/disturbance, there are no specific values for the operation and maintenance phase of Cambois connection which will occur during the operation and maintenance phase of the Proposed Development. However, Cambois connection has the potential to result in cumulative EMF effects from subsea electrical cabling within the Proposed Development. The Cambois connection is understood to comprise 680 km of cable. The effect of EMF was predicted to be of local spatial extent.
1643 The Cambois connection has the potential to create 306,000 m2 of new hard habitat associated with rock/mattress cable protection, which represents a change in seabed type, the effects of which are described in paragraph 1022 et seq. As the cable protection does not extend into the water column the opportunity for colonisation by some species is reduced, nevertheless there is a potential that placement of man-made structures on the seabed will benefit harbour porpoise population.
1644 Therefore, it can be concluded that there is no risk of an Adverse Effect on Integrity on the Southern North Sea SAC as a result of changes in fish and shellfish communities affecting prey availability during operation and maintenance with respect to the Proposed Development acting in-combination with Tier 3 projects.
Site conclusion
1645 In conclusion, with reference to the conservation objectives set for the Annex II marine mammal features of the site and the information presented in sections 13.3, 13.4, 13.5 and 13.6.4, it can be concluded beyond all reasonable scientific doubt that there will be no Adverse Effect on Integrity on the Southern North Sea SAC in respect of the harbour porpoise qualifying interests.
1646 This finding is in relation to potential impacts associated with the Proposed Development during construction, decommissioning and operation and maintenance, acting alone and or in-combination.
13.6.5 Moray Firth SAC
European site information
1647 The Moray Firth SAC is located approximately 167 km north of the Proposed Development array area and 193 km north of the Proposed Development export cable corridor. The SAC supports the only known resident population of bottlenose dolphin in the North Sea. This SAC covers an area of 1,512 km2 and extends from the inner firths to Helmsdale on the north coast and Lossiemouth on the south coast (JNCC, 2021c). The site includes areas that are regularly used by the population of bottlenose dolphins occurring along the east coast of Scotland (JNCC, 2021c). The Conservation and Management Advice document (NatureScot, 2021) states that the site reference population is the baseline population from 2005 of 101-250 individuals of bottlenose dolphin, however, NatureScot, further advised in their formal response to the HRA Stage One Screening (February 2022) that an estimated abundance of 224 individuals based on a 5-year average (2015-2019) from Arso Civil et al. (2021) should be used.
1648 Data from the site condition monitoring suggest that the proportion of the east coast of Scotland bottle nose dolphin population that use the SAC has declined, although the overall population along the coast is increasing (Cheney et al., 2018) and it is thought that their range is extending (Quick et al., 2014; Cheney et al., 2018; Arso Civil et al., 2019; Arso Civil et al., 2021).
1649 Bottlenose dolphin at the site was last assessed as being in ‘favourable maintained’ condition in September 2016.
1650 Further information on this European site is presented in appendix A.
Conservation objectives
1651 Conservation objectives for the Moray Firth SAC have been developed by NatureScot and are published as part of the Conservation and Management Advice package (NatureScot, 2021). These are as follows:
- to ensure that the qualifying features of Moray Firth SAC are in favourable condition and make an appropriate contribution to achieving Favourable Conservation Status; and
- to ensure that the integrity of Moray Firth SAC is maintained or restored in the context of environmental changes by meeting objectives 2a, 2b and 2c for each qualifying feature.
1652 For bottlenose dolphin:
- 2a: The population of bottlenose dolphin is a viable component of the site;
- 2b: The distribution of bottlenose dolphin throughout the site is maintained by avoiding significant disturbance; and
- 2c: The supporting habitats and processes relevant to bottlenose dolphin and the availability of prey for bottlenose dolphin are maintained.
1653 NatureScot (2021) states that all features are in favourable condition at Moray Firth SAC and therefore the conservation objectives seek to maintain this condition.
1654 Supplementary site-specific advice on the conservation objectives is provided in the Conservation and management package (NatureScot, 2021) and referred to in appendix A.
Features and effects for assessment
1655 The potential for adverse effects has been identified for the following Annex II marine mammal features of this site:
- Bottlenose dolphin
1656 The following impacts associated with the construction and decommissioning of the Proposed Development have been identified as having the potential for adverse effects on bottlenose dolphin at this site:
- Injury and disturbance from underwater noise generated by following activities:
– piling of fixed foundations;
– clearance of UXO;
– site investigation surveys; and
– vessel use and other activities.
- Changes in fish and shellfish communities affecting prey availability causing potential shifts in distribution, abundance and migration patterns, community structure, susceptibility to disease due to changes in prey availability.
1657 The following impacts associated with the operation and maintenance of the Proposed Development have been identified as having the potential for adverse effects on bottlenose dolphin at this site:
- Injury and disturbance from underwater noise generated by site investigation surveys as well as vessel use and other activities;
- Changes in fish and shellfish communities affecting prey availability causing potential shifts in distribution, abundance and migration patterns, community structure, susceptibility to disease due to changes in prey availability.
1658 The following assessment is structured to first assess whether the construction and decommissioning impacts will have an adverse effect on the integrity of the bottlenose dolphin feature of the site, and then the impacts associated with operation and maintenance will be assessed. For the purposes of these assessments, the potential effects are considered in relation to the site’s conservation objectives.
Construction and decommissioning
Injury and disturbance from elevated underwater noise during piling
1659 Underwater noise could affect the population and distribution of the qualifying species. Underwater noise modelling has been undertaken to estimate the maximum potential injury ranges for underwater noise that could arise during construction and decommissioning in relation to bottlenose dolphin. The modelling was based on the maximum design scenario (as outlined in Table 13.10 Open ▸ ) with summary of noise modelling provided in paragraph 834 et seq.
1660 The maximum range for injury to bottlenose dolphin was estimated as 43 m based on SPLpk and using the 4% reducing to 0.5% conversion factor (see paragraph 892 et seq). Taking into account the most conservative scenario, less than one bottlenose dolphin was predicted to be potentially injured, which accounts for <0.5% of the Moray Firth SAC population. Bottlenose dolphins from this SAC have coastal distribution within CES MU and are mostly encountered in waters between 2 m and 20 m and within 2 km from the shore. Their mostly inshore distribution has been corroborated by historic surveys undertaken across wider Firth of Forth and Tay area (Grellier and Lacey, 2011; Sparling, 2012). Therefore, this assessment is highly precautionary because it is unlikely that individuals from this SAC will be present within 43 m from piling location in offshore waters during piling activities across the Proposed Development array area. Additionally, with designed-in measures in place ( Table 13.11 Open ▸ ) which are in line with recommended best practice guidelines, the magnitude of the impact would result in a negligible risk of injury to bottlenose dolphin.
1661 In terms of behavioural disturbance, up to five animals were predicted to be potentially disturbed from concurrent piling at a maximum hammer energy of 4,000 kJ (see paragraph 929 et seq). These results are considered highly precautionary as there is a number of conservative assumptions in subsea noise model, (i.e. the maximum hammer energy of 4,000 kJ is unlikely to be reached at all piling locations (see paragraph 844 for more details)). This maximum disturbance scenario suggests that 2.2% of the bottlenose dolphin population from Moray Firth SAC have the potential to be disturbed as a result of piling, however, this is highly unlikely to be the case in reality as the assessment is based on highly precautionary densities (see paragraph 807).
1662 There is no potential for overlap of noise disturbance contours with this designated site, however, noise contours have the potential to overlap with the main distributional range of its population. Received noise levels within the 2 m to 20 m depth contour are predicted to reach maximum SELss levels of 130 dB. This is equivalent to the outer limit of the US National Marine Fisheries Service threshold (140 dBrms) for mild disturbance (NMFS, 2005) and therefore likely to elicit less severe disturbance reactions compared to higher received levels of 150 dB SELss (=160 dBrms for strong disturbance). According to the behavioural response severity matrix suggested by Southall et al. (2021) low level disturbance (scoring between 0 to 3 on 0 to 9 scale) could lead to mild disruptions of normal behaviours but prolonged or sustained behavioural effects, including displacement are unlikely to occur. Therefore, up to five animals from the Moray Firth SAC population could experience mild disturbance but this is unlikely to lead to barrier effects as animals are unlikely to be excluded from the coastal areas. Given that noise contours do not extend to the Moray Firth SAC and animals are expected to experience only mild behavioural disturbance within the CES MU, behavioural disturbance is unlikely to alter the distribution of bottlenose dolphin such that recovery cannot be expected, or effects can be considered long term.
1663 Reproductive costs in females may increase mortality, reduce offspring survival, and result in trade-offs between current and future reproduction (NatureScot, 2021). A review of the CES MU data by Quick et al. (2014), showed that males appear to spend more time outside the Moray Firth SAC than females, therefore males are more exposed to pressures outside the SAC. Given that there is a small risk that animal potentially affected by PTS will be female, there is low risk to population decline as it is highly unlikely that reproductive female will be removed from the population. Moreover, since noise contours do not reach Moray Firth SAC site there will be no behavioural disturbance with areas used by dependant mothers and calves. Therefore, it is highly unlikely that the reproductive and recruitment capability of the species will be affected.
1664 As outlined in paragraph 894, the total duration of piling could potentially affect a maximum of three breeding cycles for bottlenose dolphin. Piling activities will be intermittent and will occur over small timespan (372 days) within piling phase (52 months) and therefore can affect bottlenose dolphin over the medium term.
1665 Significant adverse effects on the qualifying Annex II marine mammal feature, bottlenose dolphin of the Moray Firth SAC, are not predicted to occur as a result of underwater noise during piling during the construction phase (i.e. in relation to maintaining the population, distribution of species within the site, connectivity and disturbance to species).
Conclusion
1666 The assessment has concluded that piling activities will not take place within the Moray Firth SAC. Given that noise contours do not extend to the Moray Firth SAC and animals are expected to experience only mild behavioural disturbance within the CES MU, behavioural disturbance will not be significant. There will be no behavioural disturbance within areas used by dependant mothers and calves, therefore it is highly unlikely that the reproductive and recruitment capability of the species will be affected. The population of bottlenose dolphin will remain a viable component of the site. Piling activities will not affect the condition of supporting habitats and processes. As such, the conservation objectives for Annex II species, bottlenose dolphin, will not be undermined.
1667 Therefore, it can be concluded that there is no risk of an Adverse Effect on Integrity of the Moray Firth SAC from injury and disturbance due to underwater noise during piling with respect to the construction of the Proposed Development acting alone.
Injury and disturbance from elevated underwater noise during site investigation surveys
1668 The noise modelling demonstrated that ranges within which there is a risk of PTS to bottlenose dolphin as a result of geophysical surveys are relatively low with a maximum impact range of 65 m (due to operation of SSS, SBES, MBES and SBP; Table 13.20 Open ▸ and Table 13.21 Open ▸ ). For geotechnical survey activities, PTS impact thresholds for bottlenose dolphin are not exceeded ( Table 13.21 Open ▸ ).
1669 There is potential for less than one animal to experience PTS as a result of geophysical and geotechnical site investigation surveys (<0.5% of the Moray Firth SAC population). It should be noted that since sonar-based systems have strong directivity, there is only potential for injury when marine mammals are directly underneath the sound source. In terms of behavioural disturbance, the largest distance over which disturbance could occur potentially affecting bottlenose dolphin is out to approximately 7.5 km during vibro-coring. Given that the vibro-core sampling locations are currently unknown and coastal distribution of bottlenose dolphin is spatially limited, any quantitative assessment of the disturbance to coastal populations would be an overestimation.
1670 As described in paragraph 800, bottlenose dolphin from Moray Firth SAC are most likely to be encountered within 2 km from the shore, therefore, in the case of surveys taking place within the Proposed Development array area, it is unlikely that individuals from this SAC will be present in offshore waters. If site investigation surveys are taking place along Proposed Development export cable corridor and nearby at the landfall at Skateraw on the East Lothian coast, there is a potential for overlap of injury/disturbance ranges with coastal areas. However, the landfall is located at the southern limit of the main distributional range of bottlenose dolphin from the Moray Firth SAC and based on the ECOMMAS study, the C‐PODs deployed at closest station at St. Abbs had very low (<5%) broadband occupancy rates for all survey years (2013 to 2015). Given that the surveys are considered to be short-term (i.e. they will take place over a period of up to three months), the number of animals potentially disturbed would represent a negligible proportion of the population.
1671 With designed-in measures in place, which are in line with recommended best practice guidelines ( Table 13.11 Open ▸ ), due to the low risk of PTS occurring and the short-term duration of the geophysical surveys, no adverse effects associated with auditory injury and disturbance to bottlenose dolphin are predicted as a result of site investigations surveys. Therefore, it is highly unlikely that site investigation surveys will influence bottlenose dolphin population trajectory in the long-term. Although there is a potential for behavioural disturbance during vibro-core survey, this survey is expected to be very short in duration with animals returning to baseline levels soon after surveys have ceased. As the site investigation surveys will take place largely outside the CES MU, also anticipated that there will be no introduction of barriers to wider movement or impact to connectivity between different important habitats for bottlenose dolphin from the Moray Firth SAC as a result of site investigation surveys.
1672 The site-investigation surveys will be taking place outside the Moray Firth SAC and there is no potential for overlap of injury ranges or noise disturbance contours with the limits of the site. Areas within the SAC are important for breeding and calving. Given that there will be no overlap of the activity with areas used by dependant mothers and calves, site investigation surveys are unlikely to affect bottlenose dolphins within the SAC at a level that would affect their behaviour and cause change in reproduction and survival rates.
1673 Significant adverse effects on the qualifying Annex II marine mammal feature, bottlenose dolphin of the Moray Firth SAC, are not predicted to occur as a result of underwater noise during site investigation surveys during the construction phase (i.e. in relation to maintaining the population, distribution of species within the site, connectivity and disturbance to species).
Conclusion
1674 The assessment has concluded that site investigation surveys will not take place within the Moray Firth SAC. Given that disturbance range do not extend to the Moray Firth SAC and only small number of animals may experience behavioural disturbance within the CES MU, behavioural disturbance will not be significant. There will be no behavioural disturbance with areas used by dependant mothers and calves, therefore it is highly unlikely that the reproductive and recruitment capability of the species will be affected. The population of bottlenose dolphin will remain a viable component of the site. Site investigation surveys will not affect the condition of supporting habitats and processes. As such, the conservation objectives for Annex II species, harbour porpoise, will not be undermined.
1675 Therefore, it can be concluded that there is no risk of an Adverse Effect on Integrity of the Moray Firth SAC from injury and disturbance due to underwater noise during site investigation surveys with respect to the construction of the Proposed Development acting alone.
Injury and disturbance from elevated underwater noise during UXO clearance
1676 Based on the maximum design scenario of high order detonation, the underwater noise modelling results show that bottlenose dolphin can be potentially affected by PTS at the maximum range of 615 m due to detonation of charge size of 300 kg ( Table 13.24 Open ▸ ). There is potential for less than one animal to experience PTS as a result of UXO clearance using high order detonation (<0.5% of the Moray Firth SAC population). It is anticipated that only 10% of all UXO clearance events will result in high order detonation as low order techniques will be applied as the intended methodology for clearance of UXO. The underwater noise modelling results show that bottlenose dolphin can be potentially affected by PTS at the maximum range of 75 m due to detonation of 0.5 kg clearance shot ( Table 13.24 Open ▸ ).
1677 To reduce the potential of experiencing injury, designed-in measures, which are in line with recommended best practice guidelines, will be adopted as part of a MMMP (see Table 13.11 Open ▸ ). There is a potential to experience auditory injury by bottlenose at a range than can be mitigated by monitoring of the 1 km mitigation zone, however, to further reduce the risk of injury, an ADD will be deployed for a pre-determined length of time to deter marine mammals to a greater distance prior to any detonation. A MMMP will be developed for the purpose of mitigating the risk of auditory injury (PTS) to marine mammals from the proposed UXO clearance activities at the Proposed Development based on an assessment which will be provided as a part of the EPS licence supporting information.
1678 Quick et al. (2014) reported that males appear to spend more time outside the Moray Firth SAC than females, therefore males are more exposed to pressures outside the SAC. Given that there is a small risk that animal potentially affected by injury will be female, there is low risk to population decline as it is highly unlikely that reproductive female will be removed from the population The UXO clearance activities will be taking place outside the Moray Firth SAC and there is no potential for overlap of injury ranges with the limits of the site. Areas within the SAC are important for breeding and calving and given that there will be no overlap of the activity with areas used by dependant mothers and calves, UXO clearance activities are unlikely to affect bottlenose dolphins at a level that would cause change in reproduction and survival rates. Therefore, UXO clearance activities are highly unlikely to affect bottlenose dolphin population in long-term.
1679 As described in paragraph 971, the threshold for potential temporary loss of hearing (TTS) was also assessed. Based on the maximum design scenario of high order detonation, the underwater noise modelling results show that bottlenose can be potentially affected by TTS at the maximum range of 1,137 m due to detonation of charge size of 300 kg ( Table 13.32 Open ▸ ).
1680 As described in paragraph 800, bottlenose dolphin from Moray Firth SAC are most likely to be encountered within 2 km from the shore. If the UXO is located within the Proposed Development array area, there is no potential for overlap of maximum injury ranges with coastal areas. If UXO clearance activities are taking place along Proposed Development export cable corridor and nearby at the landfall at Skateraw on the East Lothian coast, there is a potential for overlap of injury ranges with coastal areas. However, the landfall is located at the southern limit of the main distributional range of bottlenose dolphin from the Moray Firth SAC and based on the ECOMMAS study, the C‐PODs deployed at closest station at St. Abbs had very low (<5%) broadband occupancy rates for all survey years (2013 to 2015). Therefore it is highly unlikely that high proportion of individuals from this SAC could be potentially impacted in the vicinity of the Proposed Development export cable corridor and landfall. TTS is a temporary hearing impairment and therefore animals are likely to fully recover from the effect. Given that this effect is short in duration and will take place largely outside of the CES MU, it is anticipated that there will be no introduction of barriers to wider movement or impact to connectivity between different important habitats for bottlenose dolphin from the Moray Firth SAC as a result of UXO clearance activities.
1681 Significant adverse effects on the qualifying Annex II marine mammal feature, bottlenose dolphin of the Moray Firth SAC, are not predicted to occur as a result of underwater noise during UXO clearance during the construction phase (i.e. in relation to maintaining the population, distribution of species within the site, connectivity and disturbance to species).
Conclusion
1682 The assessment has concluded that UXO clearance will not take place within the Moray Firth SAC. Given that the TTS range do not extend to the Moray Firth SAC and only small number of animals may experience TTS within the CES MU, disturbance will not be significant. There will be no disturbance with areas used by dependant mothers and calves, therefore it is highly unlikely that the reproductive and recruitment capability of the species will be affected. The population of bottlenose dolphin will remain a viable component of the site. UXO clearance activities will not affect the condition of supporting habitats and processes. As such, the conservation objectives for Annex II species, bottlenose dolphin, will not be undermined.
1683 Therefore, it can be concluded that there is no risk of an Adverse Effect on Integrity on the Moray Firth SAC from injury and disturbance due to underwater noise during site investigation surveys with respect to the construction of the Proposed Development acting alone.
Injury and disturbance from elevated underwater noise during vessel use and other activities
1684 With regards to PTS, the modelling shows that for bottlenose dolphin, the threshold for PTS is not exceeded by any vessel with the exception of installation/construction and rock placement vessels, for which an injury range of a maximum of 15 m from the source was established ( Table 13.35 Open ▸ ). PTS ranges for bottlenose dolphin were not exceeded for any other activities except for cable laying, where an injury range of 15 m from the source was assessed. The number of bottlenose dolphin potentially affected within the modelled ranges for PTS from vessels and other activities were found to be less than one individual. For Moray Firth SAC, this equates to <0.5% of the bottlenose dolphin population. Given that vessels will follow a Code of Conduct (including advice to operators to not deliberately approach marine mammals) and NSPVMP, the risk of potential auditory injury will be reduced.
1685 With regard to behavioural disturbance to bottlenose dolphin, cable laying activities result in the greatest modelled disturbance ranges out to 4,389 m. Similar ranges for behavioural effects are predicted to occur due to underwater noise from installation and construction vessels as well as rock placement vessels with disturbance ranges of 4,389 m. In comparison, vessels such as excavator, backhoe dredger, pipe laying, geophysical survey vessel and jack up vessel as well as jack-up rig were predicted to result in disturbance ranges out to 300 m.
1686 All vessel movements will take place outside the Moray Firth SAC and there is no potential for overlap of injury or disturbance ranges with the boundaries of the site. Areas within the SAC are important for breeding and calving and given that there will be no overlap of the activity with areas used by dependant mothers and calves, vessel movements are unlikely to affect bottlenose dolphins at a level that would cause change in reproduction and survival rates. Therefore, vessel use and other activities are highly unlikely to affect bottlenose dolphin population in long-term.
1687 As described in paragraph 800, bottlenose dolphin from Moray Firth SAC are most likely to be encountered within 2 km from the shore. As most vessel movements during the construction and decommissioning will be confined within the Proposed Development array area, there is a limited potential for overlap of maximum injury or behavioural disturbance ranges with coastal areas.
1688 However, vessel movements will also be taking place along Proposed Development export cable corridor and nearby at the landfall at Skateraw on the East Lothian coast. The landfall is located at the southern limit of the main bottlenose dolphin distributional range and based on the ECOMMAS study, the C‐PODs deployed at closest station at St. Abbs had very low (<5%) broadband occupancy rates for all survey years (2013 to 2015). Therefore, if individuals are affected by disturbance as a result by vessel movements and other activities in the vicinity of the Proposed Development export cable corridor and landfall, these numbers would represent a negligible proportion of the population from Moray Firth SAC.
1689 Additionally, vessels will be moving to and from ports and harbours and this traffic will intersect with the CES MU and areas of high bottlenose dolphin abundance. The NSPVMP will be produced and will include agreed routes and potential speed restrictions in order to reduce disturbance. The Moray Firth is an area of relatively high vessel traffic due to presence of port of Cromarty Firth which has been supporting the offshore energy industry for decades. The Moray Firth SAC is located within this busy area and yet the population of bottlenose dolphin within the SAC is increasing. Therefore, given the existing levels of vessel activity within the Moray Firth and along the east coast of Scotland, it is expected that bottlenose dolphin could tolerate the effects of vessel presence. Lusseau et al. (2011) undertook a modelling study which predicted that increased vessel movements associated with offshore wind development in the Moray Firth did not have an adverse effect on the local population of bottlenose dolphin, although it did note that foraging may be disrupted by disturbance from vessels. Vessel movements intersecting the bottlenose dolphin main distributional range will be intermittent and localised and animals could be potentially disturbed from only a small area when compared to available foraging habitat. Therefore, it is anticipated that the availability of suitable foraging grounds for bottlenose dolphin will not be impaired.
1690 Given that increase in vessel movements will take place largely outside the CES MU, it is anticipated that there will be no introduction of barriers to wider movement or impact to connectivity between different important habitats for bottlenose dolphin from the Moray Firth SAC.
1691 The magnitude of the impact of the decommissioning phase for both auditory injury and disturbance as a result of elevated underwater noise due to vessel use is not expected to differ or be greater than that assessed for the construction phase (volume 2, chapter 10 of the Offshore EIA Report).
1692 Significant adverse effects on the qualifying Annex II marine mammal feature, bottlenose dolphin of the Moray Firth SAC, are not predicted to occur as a result of underwater noise during vessel use and other activities during the construction and decommissioning phases (i.e. in relation to maintaining the population, distribution of species within the site, connectivity and disturbance to species).
Conclusion
1693 The assessment has concluded that vessel use and other activities will not take place within the Moray Firth SAC. Given that the behavioural disturbance range do not extend to the Moray Firth SAC and only small number of animals may experience it within the CES MU, disturbance will not be significant. There will be no disturbance with areas used by dependant mothers and calves, therefore it is highly unlikely that the reproductive and recruitment capability of the species will be affected. The population of bottlenose dolphin will remain a viable component of the site. Vessel use and other activities will not affect the condition of supporting habitats and processes. As such, the conservation objectives for Annex II species, bottlenose dolphin, will not be undermined.
1694 Therefore, it can be concluded that there is no risk of an Adverse Effect on Integrity on the Moray Firth SAC from injury and disturbance due to underwater noise during vessel use and other activities with respect to the construction and decommissioning of the Proposed Development acting alone.
Changes in fish and shellfish communities affecting prey availability
1695 As outlined in paragraph 1010 et seq., there is potential for changes to prey availability for bottlenose dolphin during construction and decommissioning of the Proposed Development. These impacts include temporary and long-term habitat loss/disturbance, increased SSC and associated sediment deposition, and injury and/or disturbance from underwater noise and vibration.
1696 There is a potential for temporary habitat loss/disturbance to affect up to 113,974,700 m2 of seabed during the construction phase, which equates to 9.7% of the fish and shellfish ecology study area. Only a small proportion of the maximum footprint of habitat loss/disturbance may be affected at any one time during the construction phase, with areas starting to recover immediately after cessation of construction activities in the vicinity. Additionally, habitat disturbance during the construction phase will also expose benthic infaunal species from the sediment, potentially offering foraging opportunities to some fish and shellfish species (e.g. opportunistic scavenging species) immediately after completion of works. The presence of infrastructure within the Proposed Development, including foundations and associated scour protection, cable protection, OSP/Offshore convertor station platform interconnector and offshore export cables will result in long term habitat loss of up to 7,798,856 m2 (0.7% of the Proposed Development fish and shellfish ecology study area; volume 2, chapter 9 of the Offshore EIA Report). Moray Firth SAC and the Tay estuary are known to be important foraging ground for bottlenose dolphins within the CES MU (Arso Civil et al., 2021). It has been reported that seasonal changes in prey presence over variable temporal scales throughout the year may enable dolphins to exploit these areas within their range at different times. Given that neither of these important areas will be affected by temporary habitat loss/disturbance or long term habitat loss, bottlenose dolphin distribution and connectivity with important foraging habitats within and outside the site is unlikely to be impaired.
1697 Based on the analysis of stomach contents (Santos et al., 2001) and direct observations of foraging events, Salmonids are known to be important prey for bottlenose dolphins. The assessment presented in the EIA (volume 2, chapter 9 of the Offshore EIA Report) concluded that in terms of underwater noise, due to the distance between the Proposed Development array area and the coast, behavioural impacts are unlikely to cause barrier effects between the Proposed Development fish and shellfish ecology study area. Therefore the migration routes of diadromous species (including salmon Salmo salar and sea trout Salmo trutta) along the east coast of Scotland are not expected to be impaired, due to the relatively small area around piling events where noise levels are high enough to cause behavioural responses.
1699 The magnitude of the indirect impact on marine mammals as a result of changes in fish and shellfish communities during the decommissioning phase is not expected to differ or be greater than that assessed for the construction phase.
1700 Significant adverse effects on the qualifying Annex II marine mammal feature, bottlenose dolphin of the Moray Firth SAC, are not predicted to occur as a result of changes in fish and shellfish communities affecting prey availability during construction and decommissioning phases (i.e. in relation to maintaining the cover and abundance of preferred food items required by the species).
Conclusion
1701 The assessment has concluded that the impacts of construction and decommissioning will be highly localised and largely restricted to the boundaries of the Proposed Development. Given that important feeding areas within the CES MU will not be affected, the supporting habitats relevant to bottlenose dolphin and the availability of prey for bottlenose dolphin will be maintained.
1702 Therefore, it can be concluded that there is no risk of an Adverse Effect on Integrity of the Moray Firth SAC from changes in fish and shellfish communities affecting prey availability with respect to the construction and decommissioning of the Proposed Development acting alone.