Site conclusion
1258 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 13.6.1, it can be concluded beyond all reasonable scientific doubt that there will be no Adverse Effects on Integrity on the Berwickshire and North Northumberland Coast SAC in respect of the grey seal qualifying interests.
1259 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.
13.6.2 Isle of May SAC
European site information
1260 The Isle of May SAC extends over an area of 3.5 km2 (JNCC, 2015) and is located approximately 38.5 km from the Proposed Development array area and 20.9 km from the Proposed Development export cable corridor. It is located at the entrance to the Firth of Forth on the east coast of Scotland and supports the fourth largest breeding group of grey seals in the British Isles (contributes approximately 4.5% of the annual UK pup production) (JNCC, 2015). The SAC is the largest east coast breeding colony of grey seal in Scotland and comprises up to 5,900 individuals. The annual SCOS reports suggest that the population of grey seals within this SAC is increasing (e.g. SCOS, 2019; SCOS, 2020).
1261 The grey seal feature of the site was last assessed as being in ‘favourable maintained’ condition in November 2014[16].
1262 NatureScot and MS provided scoping advice in December 2021, which recommended use of SCOS (2020) pup production estimates to inform grey seal populations at Berwickshire and North Northumberland Coast SAC and Isle of May SAC. In March 2022, NatureScot and MS revised this advice following a request for clarification and recommended the use of maximum population estimates from the JNCC Standard Data Forms instead. As outlined above, this results in a population of 5,900 individuals to be considered at Isle of May SAC (JNCC, 2015ba).
1263 Further information on this European site is presented in appendix A.
Conservation objectives
1264 The conservation objectives for grey seal at Isle of May SAC have been developed by NatureScot[17] as follows:
- To avoid the deterioration of the habitat of the qualifying species or significant disturbance to the qualifying species, thus ensuring that the integrity of the site is maintained and the site makes an appropriate contribution to achieving favourable conservation status for each of the qualifying features; and
- To ensure for the qualifying species that the following are maintained in the long term:
– Population of the species as a viable component of the site;
– Distribution of the species within site
– Distribution and extent of habitats supporting the species;
– Structure, function and supporting processes of habitats supporting the species; and
– No significant disturbance of the species.
1265 No supplementary advice on the conservation objectives (similar to that available for Berwickshire and North Northumberland Coast SAC), or Conservation Advice Packages (CAP) are available for the Isle of May SAC.
Features and effects for assessment
1266 The potential for adverse effects has been identified for the following Annex II marine mammal features of this site:
- Grey seal
1267 The following impacts associated with the construction and decommissioning of the Proposed Development were identified as having the potential for adverse effects on grey seal 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 fish and shellfish communities affecting prey availability.
1268 The following impacts associated with the operation and maintenance of the Proposed Development were identified as having the potential for adverse effects on grey seal 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 fish and shellfish communities affecting prey availability.
1269 The following assessment is structured to first assess whether the construction and decommissioning impacts will have an adverse effect on the integrity of the grey seal 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
1270 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 grey seal. 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.
1271 The maximum range for injury as a result of piling to grey seal was estimated as 118 m based on SPLpk and using the 1% constant conversion factor (see paragraph 881 et seq). Taking into account the most conservative scenario, less than one grey seal was predicted to be potentially injured, which accounts for <0.02% of the Isle of May SAC population. As outlined in paragraph 780, while a relatively high proportion of tagged individuals were tracked between the Proposed Development marine mammal study area and the Isle of May SAC ( Figure 13.4 Open ▸ ), a high proportion were also tracked to the Berwickshire and North Northumberland Coast SAC, with a small proportion travelling to sites further away. Therefore, this number is likely to be an over-estimation of the proportion of seals from the Isle of May SAC affected. 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 grey seal.
1272 In terms of behavioural disturbance, up to 1,358 animals were predicted to be potentially disturbed as a result of concurrent piling at a maximum hammer energy of 4,000 kJ ( Table 13.15 Open ▸ ). 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 et seq. for more details)). This maximum disturbance scenario suggests that 24.6% of the grey seal population at Isle of May SAC have the potential to be disturbed as a result of piling, however, this is highly unlikely to be the case in reality. As outlined in paragraph 780, telemetry data showed that 41% of tagged grey seal individuals were tracked between the Proposed Development marine mammal study area and the Isle of May SAC. While there is connectivity between the SAC and the Proposed Development and there is a potential for some individuals to be present within the behavioural disturbance footprint during piling, the behavioural disturbance contours do not overlap with the SAC ( Figure 13.4 Open ▸ ). It is considered highly unlikely that 24.6% of the Isle of May population would be within the disturbance zone for the duration of piling.
1273 As outlined in paragraph 884, the total duration of piling could potentially affect a maximum of five breeding cycles for grey seals. Piling activities will be intermittent and will occur over small timespan (372 days) within piling phase (52 months) and therefore can affect grey seals over the medium term.
1274 The behavioural disturbance contours do not reach the coast and hence do not overlap with the Isle of May SAC ( Figure 13.4 Open ▸ ). Grey seals present in the vicinity of the habitats within the SAC, are therefore unlikely to experience disturbance as these areas lie outside of the noise disturbance contours. As such, piling activities are highly unlikely to disrupt normal behaviours of grey seals or adversely affect maintaining supporting habitats.
1275 Grey seal in inshore waters could experience mild disturbance where these areas overlap with 135 dB disturbance contour. To investigate the number of animals potentially disturbed in the vicinity of the SAC, a 20 km buffer around the Isle of May has been applied (based on foraging range during breeding season, see Table 8.1 Open ▸ ; Figure 13.5 Open ▸ ). Based on Carter et al. (2020) seal at-sea density grids and the area of overlap between the 20 km foraging range and the outer disturbance contour, a maximum of 18 animals could potentially experience mild disturbance within the foraging range from the Isle of May SAC. Given that animals would be potentially exposed only to low noise levels, these are unlikely to lead to barrier effects and it is expected that they will exhibit some tolerance to the mild disturbance at the coast. Therefore, disturbance caused by piling is considered unlikely to cause a change in reproduction and survival rates.
1276 During piling, there is the potential for some animals to be temporarily deterred from the offshore areas. As grey seals feed in the water column over a variety of habitats, they may use different foraging areas at different times of the year to target seasonal prey. Telemetry data suggest that adult grey seals from Isle of May SAC forage in waters to the north, north-east and east from the SAC and therefore there is a potential for individuals to forage within noise disturbance contours ( Figure 13.4 Open ▸ ). However, as described in paragraph 1084, grey seals although initially displaced due to pile-driving, are likely to return to the same area on subsequent trips following cessation of piling. Therefore, it is anticipated that piling will not result in any long-lasting changes in the distribution of adult seals from this SAC and the connectivity with areas of high importance within and outside the site is not expected to be impaired.
1277 Significant adverse effects on the qualifying Annex II marine mammal feature grey seal of the Isle of May 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).
1278
Conclusion
1279 The assessment has concluded that piling activities are highly unlikely to disrupt normal behaviours of grey seal because the behavioural disturbance contours do not reach the coast and hence do not overlap with the site. Therefore the distribution of the species within the site will not be affected and neither will be the distribution and extent of habitats supporting the species. Animals would be potentially exposed only to low noise levels along the coast and these are unlikely to lead to barrier effects or strong behavioural response. Therefore, disturbance caused by piling is considered unlikely to cause a change in reproduction and survival rates and will not influence the population of the species as a viable component of the site. As such, the conservation objectives for Annex II species, grey seal, will not be undermined.
1280 Therefore, it can be concluded that there is no risk of an Adverse Effect on Integrity on the Isle of May SAC from injury and disturbance due to underwater noise during piling with respect to the construction of the Proposed Development acting alone.
Figure 13.4: Unweighted SEL Contours Due to Concurrent Impact Piling of Wind Turbine Piles at Maximum Hammer Energy (4,000 kJ) Overlaid with Adult Grey Seal Telemetry Tracks
Figure 13.5: Unweighted SEL Contours Due to Concurrent Impact Piling Overlaid With 20 km Buffer from the Isle of May SAC
Injury and disturbance from elevated underwater noise during site investigation surveys
1281 The noise modelling showed that ranges within which there is a risk of PTS to grey seals as a result of geophysical surveys are relatively low with a maximum impact range of 65 m (due to operation of SSS, SBES and SBP; see paragraph 945 et seq.). For geotechnical survey activities, PTS impact thresholds for grey seal are not exceeded ( Table 13.21 Open ▸ ).
1282 There is potential for less than one animal to experience PTS as a result of geophysical and geotechnical site investigation surveys (<0.02% of the Isle of May SAC population). The surveys are considered to be short-term as they will take place over a period of up to three months. 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. 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 to grey seals are predicted as a result of site investigations surveys. It is anticipated that as a result of site investigation surveys there will be no introduction of barriers to wider movement or impact to connectivity between different important habitats for grey seals at the SAC as a result of elevated sound from site investigation surveys.
1284 Significant adverse effects on the qualifying Annex II marine mammal feature grey seal of the Isle of May SAC are not predicted to occur as a result of underwater noise during piling site investigation surveys the construction phase (i.e. in relation to maintaining the population, distribution of species within the site, connectivity and disturbance to species).
Conclusion
1285 The assessment has concluded that there will be no introduction of barriers to wider movement for grey seal as a result of elevated sound from site investigation surveys. Therefore the distribution of the species within the site will not be affected and neither will be the distribution and extent of habitats supporting the species. Underwater noise during site-investigation surveys is unlikely to affect grey seal at a level that would substantially affect their behaviour and cause change in reproduction and survival rates and therefore will not influence the population of the species as a viable component of the site. As such, the conservation objectives for Annex II species, grey seal, will not be undermined.
1286 Therefore, it can be concluded that there is no risk of an Adverse Effect on Integrity on the Isle of May 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 disturbance from elevated underwater noise during UXO clearance
1287 Based on the maximum design scenario of high order detonation, the underwater noise modelling results show that grey seal could be potentially affected by PTS at the maximum range of 2,085 m due to detonation of charge size of 300 kg ( Table 13.24 Open ▸ ). Conservatively, the number of grey seals that could be potentially injured by the high order UXO clearance event is up to 16 animals (Table 13.27). This represents a possible 0.3% of the Isle of May SAC population. As outlined in paragraph 780, while a relatively high proportion of tagged individuals were tracked between the Proposed Development marine mammal study area and the Isle of May SAC, a high proportion were also tracked to the Berwickshire and North Northumberland Coast SAC, with a small proportion travelling to sites further away. Therefore, this number is likely to be an over-estimation of the proportion of seals from the Isle of May SAC affected.
1288 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 ▸ ). Given that there is a potential to experience auditory injury by grey seal at a greater range than can be mitigated by monitoring of the 1 km mitigation zone alone ( Table 13.24 Open ▸ ), an ADD will be deployed for a pre-determined length of time to deter marine mammals to a greater distance prior to any detonation. Activation of ADD for 22 minutes is considered sufficient to deter grey seal from the potential injury zone as a result of high order detonation of 300 kg UXO ( Table 13.24 Open ▸ ). 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.
1289 Moreover, 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 grey seal can be potentially affected by PTS at the maximum range of 250 m due to detonation of 0.5 kg clearance shot ( Table 13.24 Open ▸ ), with one animal potentially affected ( Table 13.25 Open ▸ ). This accounts for 0.02% of the Isle of May Coast SAC population.
1290 Given that only small number of grey seals have the potential to be affected by PTS from UXO clearance events and mitigation measures are likely to reduce the risk of injury to low, an alteration in the distribution of the population from Isle of May SAC is considered highly unlikely. Additionally, grey seals present within the SAC are unlikely to experience PTS as maximum injury range is smaller than distance from the SAC to the Proposed Development area. As such, UXO clearance activities are highly unlikely to disrupt normal behaviours of grey seals or adversely affect maintaining supporting habitats.
1291 As described in paragraph 971, the threshold for potential temporary loss of hearing (TTS) was also assessed as it represents a behavioural, fleeing response. Based on the maximum design scenario of high order detonation, the underwater noise modelling results show that grey seal can be potentially affected by TTS at the maximum range of 6,430 m due to detonation of charge size of 300 kg ( Table 13.32 Open ▸ ) with up to 156 grey seal individuals affected ( Table 13.33 Open ▸ ; 2.6% of the Isle of May SAC population). As low order techniques are preferred option for UXO clearance, the underwater noise modelling results show that grey seal can potentially experience TTS at the maximum range of 455 m due to detonation of 0.5 kg clearance shot ( Table 13.30 Open ▸ ) with up to one grey seal potentially affected ( Table 13.31 Open ▸ ). This accounts for 0.02% of the Isle of May SAC population.
1292 TTS is a temporary hearing impairment and therefore animals are likely to fully recover from the effect. Therefore, effects caused by UXO clearance are considered unlikely to cause a change in reproduction and survival rates or alteration in the distribution of the population from Isle of May SAC. Given that this effect is short in duration, connectivity with important habitats within and outside the site is also unlikely to be impaired.
1293 Considering the number of animals potentially affected by the PTS and TTS and respective proportions of the SAC population potentially affected, it is highly unlikely that UXO clearance will influence grey seal population trajectory in the long-term.
1294 Significant adverse effects on the qualifying Annex II marine mammal feature grey seal of the Isle of May 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
1295 The assessment has concluded that UXO clearance activities are highly unlikely to disrupt normal behaviours of grey seal. Since TTS is a temporary hearing impairment, it is unlikely to cause a change in reproduction and survival rates and will not influence the population of qualifying species. Changes in distribution of qualifying species within the site are highly unlikely. As such, the conservation objectives for Annex II species, grey seal, will not be undermined.
1296 Therefore, it can be concluded that there is no risk of an Adverse Effect on Integrity on the Isle of May SAC from injury and disturbance due to underwater noise during UXO clearance with respect to the construction of the Proposed Development acting alone.
Injury and disturbance from elevated underwater noise during vessel use and other activities
1297 With regards to PTS, the modelling shows that for grey seal, the threshold for PTS is not exceeded by any vessel with the exception of rock placement vessels, for which an injury range of 5 m from the source was reported ( Table 13.36 Open ▸ ). PTS ranges for grey seal were not exceeded for any other activities except for cable laying, where an injury range of 5 m from the source was reported. The number of grey seals potentially affected within the modelled ranges for PTS from vessels and other activities were found to be less than one individual. For Isle of May SAC, this equates to <0.02% of the grey seal population. As outlined in paragraph 780, while a relatively high proportion of tagged individuals were tracked between the Proposed Development marine mammal study area and the Isle of May SAC, a high proportion were also tracked to the Berwickshire and North Northumberland Coast SAC, with a small proportion travelling to sites further away. Therefore, this number is likely to be an over-estimation of the proportion of seals from the Isle of May SAC affected. 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 low.
1298 With regard to behavioural disturbance to grey seals, 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.
1299 As discussed in paragraph 874, there is likely to be a proportionate response of animals within the modelled contours (i.e. not all animals will be disturbed to the same extent). Grey seal is likely to be sensitive to disturbance from vessel traffic. However, most of the vessel traffic associated with construction and decommissioning will take place within the Proposed Development array area and Proposed Development export cable corridor, at a distance where overlap of noise disturbance contours ( Table 13.37 Open ▸ ) with the Isle of May SAC is unlikely. It is therefore highly unlikely that the reproductive and recruitment capability of the species will be affected. Construction activities will be carried out over a medium term and since the behavioural effect is considered to be highly reversible, it is highly unlikely that it will influence grey seal population trajectory in the long-term.
1300 Most of the vessel traffic associated with construction within the Proposed Development array area will take place at distances >40 km from the Isle of May SAC. Vessel movements will also increase over construction phase along the Proposed Development export cable corridor. However, due to the distance from the SAC (approximately 20 km) there is no potential for overlap of disturbance ranges with the site.
1301 As previously described in paragraph 1107, Anderwald et al. (2013) suggested that in the study of displacement responses to construction-related vessel traffic, grey seals were avoiding the area due to vessel noise. Even if individuals are temporarily deterred from offshore foraging grounds, given that the impacts of construction will be highly localised and largely restricted to the boundaries of the Proposed Development, only a small area will be affected when compared to available foraging habitat for grey seals in the northern North Sea. Therefore, availability of foraging grounds for grey seals from the Isle of May SAC will not be significantly impacted.
1302 As outlined in paragraph 1110, foraging context is important when interpreting avoidance behaviour of grey seals and should be considered when predicting effects. Avoidance rates may depend on perceived risk versus the quality of the prey patch. Given the existing levels of vessel activity in the Proposed Development shipping and navigation study area it is expected that grey seal could tolerate the effects of disturbance without any impact on reproduction and survival rates and would return to previous activities once the impact had ceased.
1303 Significant adverse effects on the qualifying Annex II marine mammal feature grey seal of the Isle of May SAC are not predicted to occur as a result of underwater noise during vessel use and other activities during the construction phase (i.e. in relation to maintaining the population, distribution of species within the site, connectivity and disturbance to species).
Conclusion
1304 The assessment has concluded that vessel use and other activities are highly unlikely to affect reproductive and recruitment capability of the species because the behavioural disturbance ranges do not reach the coast and hence do not overlap with the site. Therefore, it will not influence the population of the species as a viable component of the site. The availability of foraging grounds for grey seal will not be impacted and the distribution of the species within the site will not be affected and neither will be the distribution and extent of habitats supporting the species. As such, the conservation objectives for Annex II species, grey seal, will not be undermined.
1305 Therefore, it can be concluded that there is no risk of an Adverse Effect on Integrity on the Isle of May 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
1306 As outlined in paragraph 1010 et seq., there is potential for changes to prey availability for grey seal 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.
1307 There is 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 (see volume 2, chapter 9 of the Offshore EIA Report). 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. It is expected that grey seal could come back to forage within areas previously disturbed after cessation of works and therefore their distribution and connectivity with important habitats within and outside the site is unlikely to be impaired in long term. As presented in volume 2, chapter 9 of the Offshore EIA Report, monitoring studies have shown that offshore wind farm construction has not led to significant adverse effects on sandeel populations and that recovery of sandeel occurs quickly following construction operations (Jensen et al., 2004).
1308 In terms of indirect effects on marine mammals as a result of underwater noise, it is assumed that marine mammals would be disturbed from the area in vicinity of the noise source, and so any changes to the distribution of prey resources would not affect marine mammals as they would already be disturbed from the same (or larger) area. It is expected that grey seal population would be able to tolerate the effect without any impact on reproduction and survival rates.
1310 As outlined in paragraph 1023 et seq., while grey seal has a relatively selective diet of predominantly flatfish and sandeel, the species can forage widely, sometimes covering extensive distances. Given that the impacts of construction will be highly localised and largely restricted to the boundaries of the Proposed Development, only a small area will be affected when compared to available foraging habitat for grey seals in the northern North Sea. Telemetry data showed wide-ranging behaviour of grey seals within the northern North Sea, suggesting that, due to the highly mobile nature of grey seals and presence of alternative prey resources and foraging grounds available in the wider area, grey seals will not be constrained by the temporary and reversable nature of impacts associated with construction. There may be an energetic cost associated with increased travelling, however, grey seal is not considered to be particularly vulnerable to this effect as foraging trips tend to be wide-ranging, out to 100 km from a haul out site (SCOS, 2018). It is expected that grey seal population would be able to tolerate the effect without any impact on reproduction and survival rates.
1311 There will be no direct overlap of Proposed Development with the Isle of May SAC. Based on the telemetry data it is highly unlikely that all grey seal foraging within the Proposed Development would be from this SAC ( Figure 13.4 Open ▸ ). As outlined in paragraph 780, while a relatively high proportion of tagged individuals were tracked between the Proposed Development marine mammal study area and the Isle of May SAC, a high proportion were also tracked to the Berwickshire and North Northumberland Coast SAC, with a small proportion travelling to sites further away.
1312 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.
1313 Significant adverse effects on the qualifying Annex II marine mammal feature grey seal of the Isle of May 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
1314 The assessment has concluded that distribution of the species within the site and the distribution and extent of habitats supporting the species is unlikely to be impaired in long term. It is expected that grey seal population would be able to tolerate the effect of changes in fish and shellfish communities without any impact on reproduction and survival rates and it will not influence the population of the species as a viable component of the site. As such, the conservation objectives for Annex II species, grey seal, will not be undermined.
1315 Therefore, it can be concluded that there is no risk of an Adverse Effect on Integrity on the Isle of May SAC om changes in fish and shellfish communities affecting prey availability with respect to the construction and decommissioning of the Proposed Development acting alone.
Operation and maintenance
Injury and disturbance from elevated underwater noise during site investigation surveys
1316 As discussed in paragraph 945 et seq., the maximum range at which there is a risk of PTS to grey seal as a result of site investigation surveys is 65 m. With designed in measures ( Table 13.40 Open ▸ ) implemented for the geophysical surveys, the risk of PTS occurring to grey seals will be low. With regard to behavioural disturbance, although a maximum potential disturbance range across all survey types is approximately 7.5 km during vibro-coring, this survey is expected to be very short in duration with animals returning to baseline levels soon after surveys have ceased. It is anticipated that there will be no introduction of barriers to wider movement or impact to connectivity between different important habitats for grey seals at the SAC as a result of site investigation surveys.
1317 The maximum design scenario for routine geophysical surveys is estimated as a survey every six months for the first two years and annually thereafter. This equates to 37 surveys over the 35-year life cycle of the Proposed Development ( Table 13.39 Open ▸ ). The magnitude of the impact could result in a negligible alteration to the distribution of grey seals. Surveys are anticipated to be short-term in nature (weeks to a few months) and occur intermittently over the operation and maintenance phase. Given no overlap between the Proposed Development and Isle of May SAC is expected, only a small proportion of grey seal SAC population could be potentially affected and they would be able to tolerate the effect without any impact on reproduction and survival rates. Therefore, it is highly unlikely that site investigation surveys will influence grey seal population trajectory in the long-term.
1318 Significant adverse effects on the qualifying Annex II marine mammal feature grey seal of the Isle of May SAC are not predicted to occur as a result of underwater noise during site investigation surveys during the operation and maintenance phase (i.e. in relation to maintaining the population, distribution of species within the site, connectivity and disturbance to species).
Conclusion
1319 The assessment has concluded that there will be no introduction of barriers to wider movement for grey seal as a result of elevated sound from site investigation surveys. Therefore the distribution of the species within the site will not be affected and neither will be the distribution and extent of habitats supporting the species. Underwater noise during site-investigation surveys is unlikely to affect grey seal at a level that would substantially affect their behaviour and cause change in reproduction and survival rates and therefore will not influence the population of the species as a viable component of the site. As such, the conservation objectives for Annex II species, grey seal, will not be undermined.
1320 Therefore, it can be concluded that there is no risk of an Adverse Effect on Integrity on the Isle of May SAC from injury and disturbance due to underwater noise during site investigation surveys with respect to the operation of the Proposed Development acting alone.
Injury and disturbance from elevated underwater noise during vessel use and other activities
1321 As described in paragraphs 1044 et seq., vessel use during the operation and maintenance phase of the Proposed Development is considered a relatively small increase in the context of baseline traffic and the size and noise outputs from vessels will be similar to those used in the construction phase. The number of vessel round trips and their frequency will be much lower compared to the construction phase.
1322 Most of the vessel traffic associated with operation and maintenance within the Proposed Development array area will take place at distances >40 km from the Isle of May SAC. It can be anticipated that the number of vessel movements will increase during the operation and maintenance phase along the Proposed Development export cable corridor when compared to baseline levels. However, due to the distance from the landfall to the SAC, there is no potential for overlap of disturbance ranges with the site.
1323 Given the existing levels of vessel activity in the Proposed Development shipping and navigation study area (see volume 2, chapter 13 of the Offshore EIA Report) it is expected that grey seal could tolerate the effects of disturbance without any impact on reproduction and survival rate. There will be no introduction of barriers to wider movement or impact to connectivity between different important habitats for grey seals at the SAC.
1324 Given that risk of injury will be reduced as vessels will follow a Code of Conduct and since the behavioural effect is considered to be highly reversible, it is highly unlikely that vessel use and other activities will influence grey seal population trajectory in the long-term.
1325 Effects on grey seal at the Isle of May SAC are therefore considered to be the same or less than the effects described for vessel use and other activities during the construction and decommissioning phases. It should be noted that operation and maintenance activities will occur over the full lifetime of the project (estimated to be 35 years) and therefore only a small proportion of vessel use and other activities will occur at any one time.
1326 Significant adverse effects on the qualifying Annex II marine mammal feature grey seal of the Isle of May SAC are not predicted to occur as a result of underwater noise during vessel use and other activities during the operation and maintenance phase (i.e. in relation to maintaining the population, distribution of species within the site, connectivity and disturbance to species).
Conclusion
1327 The assessment has concluded that vessel use and other activities are highly unlikely to affect reproductive and recruitment capability of the species because the behavioural disturbance ranges do not reach the coast and hence do not overlap with the site. Therefore, it will not influence the population of the species as a viable component of the site. The availability of foraging grounds for grey seal will not be impacted and the distribution of the species within the site will not be affected and neither will be the distribution and extent of habitats supporting the species. As such, the conservation objectives for Annex II species, grey seal, will not be undermined.
1328 Therefore, it can be concluded that there is no risk of an Adverse Effect on Integrity on the Isle of May SAC from injury and disturbance due to underwater noise during vessel use and other activities with respect to the operation of the Proposed Development acting alone.