Operation and maintenance phase

Magnitude of impact

629. The operation and maintenance activities of the Proposed Development will overlap with Tier 2 projects identified in Table 10.55   Open ▸ and may lead to disturbance to marine mammals from vessel use and other activities. Projects screened into this assessment include disposal activities at the Eyemouth disposal site, the operation and maintenance of Inch Cape Offshore Wind Farm, Seagreen 1, Seagreen 1A Project, Eastern Link 1, Eastern Link 2, Blyth Demo 2, and Neart na Gaoithe Offshore Wind Farm.
630. The construction of the Proposed Development overlaps with the operation and maintenance phase of the respective projects, and therefore, where available, the number and types of vessel associated with operation and maintenance of projects considered in the cumulative assessment along with assessment of significance are provided in paragraph 610 et seq.
631. The maximum design scenario for the operation and maintenance phase of the Proposed Development is presented in Table 10.16   Open ▸ with up to 2,323 vessel round trips per year over the operational lifetime of the Project. Vessel use during the operation phase of the Proposed Development is described in more detail in paragraph 383 et seq. The impacts due to disturbance to marine mammals from vessel use and other activities for the Proposed Development alone during the operation and maintenance phase were assessed as negligible to minor.
632. Vessels involved in the operation and maintenance of other wind farms will include a similar suite of vessels as those described for the Proposed Development alone (see paragraph 383 et seq.), such as vessels used during routine inspections, repairs and replacement of equipment, major component replacement, painting or other coatings, removal of marine growth and replacement of access ladders. Given that the number of vessel round trips and their frequency is much lower for the operation and maintenance phases compared to construction phases of the respective projects, the magnitude of the impact for disturbance as a result of elevated underwater noise due to vessel use and other activities, for all marine mammal receptors, is expected to be less than that assessed for the construction phase. However, the duration of the effect will be longer (over the 35-year operating lifetime of the Proposed Development) and therefore a precautionary approach has been taken in assessing the magnitude.
633. During the operation and maintenance phase of the Proposed Development, the other Tier 2 wind farms will reach their decommissioning age before the Proposed Development reaches its decommissioning age in 2066. The operational lifetime of Inch Cape is expected to be up to 35 years, with construction ending in 2025 and decommissioning expected in 2060 (Inch Cape Offshore Ltd, 2018). The operational lifetime of Neart na Gaoithe is expected to be 25 years, with construction ending in 2023 and decommissioning expected in 2048 (Mainstream Renewable Power, 2019). Seagreen 1 and Seagreen 1A Project have an operation and maintenance phase of 25 – 30 years which will lead to their decommissioning in 2048 – 2053 (Seagreen Wind Energy Ltd, 2012). The environmental statements for offshore wind farms listed in paragraph 630 predicted the number and type of vessels associated with decommissioning are expected to be, at worst, similar to construction. Therefore, the cumulative magnitude of the impact of the decommissioning phase as a result of elevated underwater noise due to vessel use, for all marine mammal receptors, are considered to be equivalent to and potentially lower than the maximum adverse scenario effects assessed for the construction phase.
634. Additionally, it can be expected that after more than ten years of construction activities taking place in the vicinity of Firth of Forth (i.e. Seagreen 1 construction activities commenced in 2021 and the operation and maintenance phase of Proposed Development is expected to start from 2033), marine mammals present in the area will demonstrate some degree of habituation to ship noises.
635. The cumulative impact is predicted to be of local spatial extent, long term duration, intermittent and the effect of disturbance is of high reversibility. It is predicted that the impact will affect the receptor directly. The magnitude is therefore, considered to be low.

Sensitivity of receptor

636. The sensitivity of marine mammals to cumulative disturbance from elevated underwater noise due to vessel use and other activities is as described in paragraph 624 et seq. for the construction phase.
637. All marine mammals, which are IEFs of international value, are deemed to be of low vulnerability and high recoverability. The sensitivity of the receptor is therefore considered to be medium.

Significance of effect

638. Overall, the magnitude of the cumulative impact is deemed to be low and the sensitivity of the receptor is considered to be medium. Cumulatively, the effect will therefore be of minor adverse significance, which is not significant in EIA terms.

Further mitigation and residual effect

639. No secondary marine mammal mitigation is considered necessary as the predicted effect in the absence of further mitigation (beyond the designed in measures outlined in section 10.10) is not significant in EIA terms. Therefore, the residual effect is considered to be of minor adverse significance, which is not significant in EIA terms.

Tier 3

Construction phase

640. The construction of the Proposed Development, together with Tier 3 projects identified in Table 10.55   Open ▸ may lead to disturbance to marine mammals from vessel use and other activities. Projects screened into this assessment include the construction and operation of Cambois connection and operation of Forthwind Demonstration Project.
641. The scoping report for the Forthwind Offshore Wind Demonstration Project concluded, that due to the small scale of deployment, the industrial nature of the location and relatively low presence of marine mammals, operational effects such as increased vessel movements were scoped out from further assessment (Cierco, 2019).
642. There is currently no information on the impacts the Cambois connection will have on marine mammal IEFs, although the Scoping Report have listed the types of vessels to be used during construction, including cable lay vessels, pre-lay survey vessels, rock protection vessels, support vessels, guard vessels, and possible use of jack-up vessels (SSER, 2022e). There are no details about number of vessel round trips during the construction phase of Cambois connection.
643. Due to lack of project information at this stage, it is not possible to undertake full, quantitative assessment for this impact and therefore a qualitative assessment is provided in paragraph 645 et seq.

Magnitude of impact

644. Behavioural effects on marine mammal may extend beyond the boundaries of the projects listed in paragraph 641, although the extent to which this occurs will depend on the design parameters. The maximum range over which potential disturbance may occur for the Proposed Development alone as a result of drilled piling and jet trenching, is predicted out to 1,900 m and 2,580 m, respectively. Cable installation activities assessed for the Proposed Development alone have the potential to disturb marine mammals out to 4,389 m. Although the range of effects for each respective project is predicted to be localised, given the distances from the Proposed Development (see Table 10.54   Open ▸ for distances) there is a potential for overlap in the behavioural ZoI. And cumulatively, construction activities could lead to a larger area of disturbance and larger number of animals disturbed across the regional marine mammal study area compared to the Proposed Development alone if projects were to conduct construction activities over similar time periods. However, the scale of the disturbance effects is considered to be small in the context of the wider habitat available.
645. The cumulative impact is predicted to be of local spatial extent, short term duration, intermittent and behavioural effects are of high reversibility. It is predicted that the impact will affect the receptor directly. The magnitude is therefore, considered to be low.

Sensitivity of receptor

646. The sensitivity of marine mammals to cumulative disturbance from elevated underwater noise due to vessel use and other activities is as described in paragraph 624 et seq. for the construction phase.
647. All marine mammals, which are IEFs of international value, are deemed to be of low vulnerability and high recoverability. The sensitivity of the receptor is therefore considered to be medium.

Significance of effect

648. Overall, the magnitude of the cumulative impact is deemed to be low and the sensitivity of the receptor is considered to be medium. Cumulatively, the effect will therefore be of minor adverse significance, which is not significant in EIA terms.

Further mitigation and residual effect

649. No secondary marine mammal mitigation is considered necessary as the predicted effect in the absence of further mitigation (beyond the designed in measures outlined in section 10.10) is not significant in EIA terms. Therefore, the residual effect is considered to be of minor adverse significance, which is not significant in EIA terms.

Operation and maintenance phase

650. The operation of the Proposed Development, together with Tier 3 projects identified in Table 10.55   Open ▸ may lead to disturbance to marine mammals from vessel use and other activities. Projects screened into this assessment include the operation of Cambois connection and Forthwind Demonstration Project.
651. The scoping report for the Forthwind Offshore Wind Demonstration Project concluded, that due to the small scale of deployment, the industrial nature of the location and relatively low presence of marine mammals, operational effects such as increased vessel movements were scoped out from further assessment (Cierco, 2019).
652. As presented in paragraph 643, there were no details about the number of vessel round trips or type of vessels that will be used during operation and maintenance phase of Cambois connection (SSER, 2022e).
653. Due to lack of detailed project information at this stage, it was not possible to undertake full, quantitative assessment for this impact.

Magnitude of impact

654. An overview of potential impacts for behavioural disturbance to marine mammals from elevated underwater noise due to vessel use and other activities is described in paragraph 645 et seq. for the construction phase and have not been reiterated here for the operation and maintenance phase.
655. The cumulative impact is predicted to be of local spatial extent, short term duration, intermittent and behavioural effects are of high reversibility. It is predicted that the impact will affect the receptor directly. The magnitude is therefore considered to be low.

Sensitivity of receptor

656. The sensitivity of marine mammals to cumulative disturbance from elevated underwater noise due to vessel use and other activities is as described in paragraph 624 et seq. for the construction phase.
657. All marine mammals, which are IEFs of international value, are deemed to be of low vulnerability and high recoverability. The sensitivity of the receptor is therefore, considered to be medium.

Significance of effect

658. Overall, the magnitude of the cumulative impact is deemed to be low and the sensitivity of the receptor is considered to be medium. Cumulatively, the effect will therefore be of minor adverse significance, which is not significant in EIA terms.

Further mitigation and residual effect

659. No secondary marine mammal mitigation is considered necessary as the predicted effect in the absence of further mitigation (beyond the designed in measures outlined in section 10.10) is not significant in EIA terms. Therefore, the residual effect is considered to be of minor adverse significance, which is not significant in EIA terms.

Injury of Marine Mammals Due to Collision with Vessels

Tier 2

Construction phase

Magnitude of impact

660. The construction of the Proposed Development, together with Tier 2 projects and plans identified in Table 10.55   Open ▸ , may lead to increased risk of collision with vessels. Projects screened into this assessment include the construction and operation and maintenance of Inch Cape Offshore Wind Farm, Seagreen 1A Project, Blyth Demo 2, Eastern Link 1 and Easter Link 2 and operation and maintenance of Neart na Gaoithe Offshore Wind Farm and Seagreen 1.
661. The number and types of vessel associated with construction of Proposed Development as well as construction and/or operation and maintenance of projects considered in the cumulative assessment is provided in paragraph 610 et seq. Collision risk and barrier effect from increased vessel movements were assessed as minor (not significant) in the original Inch Cape Offshore Wind Farm EIA for both, the construction as well as operation and maintenance phases (Inch Cape Offshore Ltd, 2014). Given that the revised version of the project predicted smaller number of vessel movements during operation and maintenance phase, it is anticipated to have less of an impact and therefore it has been scoped out from the revised Inch Cape Offshore Wind Farm EIA (Inch Cape Offshore Ltd Scoping Report, 2017). The risk of collision during the construction as well as operation and maintenance phase has been assessed as negligible for Seagreen 1A Project  and Seagreen 1 (Seagreen Wind Energy Ltd, 2012). The Neart na Gaoithe EIA assessed a potential for injury as a result of collision with vessels as not significant during operation and maintenance (Mainstream Renewable Power, 2012). The Environmental Appraisal Reports for Eastern Link 1 and Eastern Link 2 assessed the likelihood of vessel collision with marine mammals during installation as unlikely and, therefore, the effect of this impact has been assessed as minor (AECOM, 2022a; AECOM, 2022b). The assessment of impacts on marine mammals as collision during the maintenance and operation and maintenance phase of the Eastern Link 1 and Eastern Link 2 is unavailable.
662. The original Blyth Offshore Demonstration Project EIA Report assessed a potential for injury as a result of collision during installation 15 monopiles (NAREC, 2012). Potential effects of collision risk impacts were concluded as low magnitude (NAREC, 2012). A review of the assessment of effects for marine mammals was undertaken as part of the 2013 SEI but it did not lead to any change in the conclusions of the original EIA (NAREC, 2013). Blyth Demo 2 will include construction of floating platforms, that will be built at the quayside and towed to site. Therefore, construction can be achieved more quickly than traditional offshore wind turbine construction assessed in original EIA Report (NERC, 2012) and does not rely on as many vessels or specialised vessels. The exact number of round vessel trips was not provided in the original EIA Report (NAREC, 2012); however, the potential for collision with vessels during construction and operation of the Blyth Demo 2 are considered to be less or equivalent when compared to existing consent where it was assessed as low (EDF, 2020).
663. The impacts to marine mammals due to collision risk for the Proposed Development alone during the construction phase were assessed as minor.
664. Given that vessel movements will be confined to the array areas and/or offshore export cable corridor routes and will follow existing shipping routes to/from port, the risk of collision to marine mammals is expected to be localised to within the boundaries of the respective projects. As presented in more detail in volume 2, chapter 13, commercial vessels associated with other projects and maritime activities will not transit through Proposed Development array area. The types of vessels involved in construction activities at the other offshore wind farms will be similar to those identified for construction of the Proposed Development, such as jack-up vessels, tug/anchor handers, cable installation vessels, scour/cable protection installation vessel, guard vessels, survey vessels and CTVs. As previously described for the Proposed Development alone (see paragraph 404 et seq.), vessels travelling at 7 m/s or faster are those most likely to cause death or serious injury to marine mammals (Laist et al., 2001). Vessels involved in the construction phase of Proposed Development and respective projects are likely to be travelling considerably slower than this. There is also a potential that the noise emissions from vessels will deter animals from the potential zone of impact.
665. The Proposed Development and respective projects are located in the area of relatively high vessel traffic (see paragraph 354 et seq.) and therefore it can be expected that marine mammals present in the vicinity of Firth of Forth will demonstrate some degree of habituation to the presence of high number of vessels. As previously stated in paragraph 620 et seq, the commercial vessel numbers in the vicinity of Proposed Development are expected to remain reasonably consistent in the future. In the longer term, there may be increases in wind farm related traffic associated with the ScotWind developments north and east of the Proposed Development. However, given the low data confidence associated with these developments it was not possible to make any quantitative assumptions. It is anticipated that the risk of collision at other offshore wind farm projects would be minimised through the adoption of factored-in measures such as vessel codes of conduct as standard good practice for offshore wind developments. Therefore, even with a cumulative increase in vessel traffic, the type of vessels involved and transit routes is unlikely to impose a greater risk to marine mammals.
666. The cumulative impact of collision risk is predicted to be of local spatial extent, medium term duration, intermittent and low reversibility. It is predicted that the impact will affect the receptor directly. Given the minor temporal overlap in construction activities and that the operation and maintenance activities associated with the relevant projects will not add substantially to the total number of vessel round trips associated with the Proposed Development, with only a proportion of the operation and maintenance operations occurring during the construction phase of the Proposed Development, the magnitude of the impact will not be greater than that assumed for the project alone. The magnitude is therefore, considered to be low.

Sensitivity of receptor

667. The sensitivity of marine mammals to collision risk is as described in section 10.11, paragraph 400 et seq.
668. As presented above for vessel noise and other activities sensitivity section (paragraph 622 et seq.) the link between vessel movements and reduced marine mammal activity is not straightforward to establish due to intrinsic factors that may also contribute to a variance in distribution and abundance (e.g. changes in prey distribution and natural seasonal fluctuations). Harbour and grey seals at sea within the vicinity of the haul-outs in the inner Firth of Forth are likely to be exposed to existing high levels of vessel activity to/from busy ports and harbours in the area (e.g. Rosyth, Braefoot Bay, Methill and North Berwick). Therefore, seals in the vicinity of haul-out sites are anticipated to demonstrate some degree of habituation to presence of ships. Nevertheless, collision risk is anticipated to be higher in the vicinity of haul-out sites, particularly for young seals that have no previous experience of vessel traffic. Vessels associated with the Proposed Development would follow a Code of Conduct, included as a part of the NSPVMP (volume 4, appendix 25), which would include, for example, limiting the speed of vessels near haul-outs, avoiding sudden changes in direction, and refraining from approaching animals in the water ( Table 10.21   Open ▸ ).
669. It is assumed that vessels will follow a Code of Conduct for vessel operators, therefore reducing the risk. However, although the potential to experience injury from construction traffic is relatively low, the consequences of collision risk, could be fatal. All marine mammals would have limited tolerance to a collision risk, and the effect of the impact could cause a change in both reproduction and survival of individuals, and receptors would have limited ability for the animal to recover from the effect.
670. All marine mammals, which are IEFs of international value, are deemed to be of medium vulnerability and medium recoverability. The sensitivity of the receptor is therefore considered to be medium.

Significance of effect

671. Overall, the magnitude of the cumulative impact is deemed to be low and the sensitivity of the receptor is considered to be medium. The cumulative effect will, therefore, be of minor adverse significance, which is not significant in EIA terms.

Further mitigation and residual effect

672. No secondary marine mammal mitigation is considered necessary as the predicted effect in the absence of further mitigation (beyond the designed in measures outlined in section 10.10) is not significant in EIA terms. Therefore, the residual effect is considered to be of minor adverse significance, which is not significant in EIA terms.

Operation and maintenance phase

Magnitude of impact

673. The operation and maintenance activities of the Proposed Development will overlap with the operation and maintenance phase of the projects identified in Table 10.55   Open ▸ and may lead to increased risk of collision with vessels. Other projects screened into this assessment include the operation and maintenance of Inch Cape Offshore Wind Farm, Seagreen 1A Project, Seagreen 1, Eastern Link 1, Eastern Link 2, Blyth Demo 2 and Neart na Gaoithe Offshore Wind Farm.
674. Given that the construction of the Proposed Development overlaps with the operation and maintenance phase of the respective projects, the number and types of vessel associated with operation and maintenance of projects considered for operation and maintenance phase are provided in paragraph 610 et seq. An overview of potential effects due to collision with vessels along with assessment of significance for the operation and maintenance phase for Inch Cape, Seagreen 1A Project, Seagreen 1 and Neart na Gaoithe Offshore Wind Farm is presented in paragraph 661 et seq. An overview of potential effects due to collision with vessels during construction and operation of the Blyth Demo 2 is presented and paragraph 663, where it was assessed as low.
675. The maximum scenario for the operation and maintenance phase of the Proposed Development is presented in Table 10.16   Open ▸ with up to 2,323 vessel round trips per year over the operational lifetime of the Project. Vessel use during the operation phase of the Proposed Development is described in more detail in paragraph 383 et seq. The impacts due to injury of marine mammals due to collision risk for the Proposed Development alone during the operation and maintenance phase were assessed as minor.
676. Given that vessel movements will be confined to the array areas and/or offshore export cable corridor routes and will follow existing shipping routes to/from port, the risk of collision to marine mammals is expected to be localised to within the boundaries of the respective projects.
677. The types of vessels involved in operation and maintenance activities at the other offshore wind farms will be similar to those identified for the Proposed Development, such as vessels used during routine inspections, repairs and replacement of equipment, major component replacement, painting or other coatings, removal of marine growth and replacement of access ladders. The number of vessel movements during the operation and maintenance phase represents a slight increase in the risk of collision for marine mammals over the existing levels of vessel traffic. There is also a potential that the noise emissions from vessels will deter animals from the potential zone of impact.
678. Additionally, it can be expected that after more than ten years of construction activities taking place in the vicinity of Firth of Forth (i.e. Seagreen 1 construction activities commenced in 2021 and the operation and maintenance phase of Proposed Development is expected to start from 2033), marine mammals present in the area will demonstrate some degree of habituation to the presence of high number of vessels. It is anticipated that the risk of collision at other offshore wind farm projects would be minimised through the adoption of factored in measures such as vessel codes of conduct as standard good practice for offshore wind developments. Therefore, even with a cumulative increase in vessel traffic, the type of vessels involved and transit routes is unlikely to impose a greater risk to marine mammals.
679. During the operation and maintenance phase of the Proposed Development, the other Tier 2 wind farms will reach their decommissioning age before the Proposed Development reaches its decommissioning age in 2066. The operational lifetime of Inch Cape is expected to be up to 35 years, with construction ending in 2025 and decommissioning expected in 2060 (Inch Cape Offshore Ltd, 2018). The operational lifetime of Neart na Gaoithe is expected to be 25 years, with construction ending in 2023 and decommissioning expected in 2048 (Mainstream Renewable Power, 2019). Seagreen 1 and Seagreen 1A Project have an operation and maintenance phase of 25 – 30 years which will lead to its decommissioning in 2048 – 2053 (Seagreen Wind Energy Ltd, 2012). The environmental statements for offshore wind farms listed above predicted the number and type of vessels associated with decommissioning are expected to be, at worst, similar to construction. Therefore, the cumulative magnitude of the impact of the decommissioning phase as a result of collision with vessels, for all marine mammal receptors, are considered to be equivalent to and potentially lower than the maximum adverse effects assessed for the construction phase.
680. The cumulative impact is predicted to be of local spatial extent, long term duration, intermittent and effects are of low reversibility. It is predicted that the impact will affect the receptor directly. The magnitude is therefore, considered to be low.

Sensitivity of receptor

681. The sensitivity of marine mammals to cumulative collision risk is as described for construction phase above in paragraph 668 et seq.
682. All marine mammals, which are IEFs of international value, are deemed to be of medium vulnerability and medium recoverability. The sensitivity of the receptor is therefore considered to be medium.

Significance of effect

683. Overall, the magnitude of the cumulative effect is deemed to be low and the sensitivity of the receptor is considered to be medium. The cumulative effect will, therefore, be of minor adverse significance, which is not significant in EIA terms.

Further mitigation and residual effect

684. No secondary marine mammal mitigation is considered necessary as the predicted effect in the absence of further mitigation (beyond the designed in measures outlined in section 10.10) is not significant in EIA terms. Therefore, the residual effect is considered to be of minor adverse significance, which is not significant in EIA terms.

Tier 3

Construction phase

685. The construction of the Proposed Development, together with Tier 3 projects identified in Table 10.55   Open ▸ may lead to cumulative effects as a result of collision risk. Projects screened into this assessment include the construction and operation Cambois connection and operation of Forthwind Demonstration Project.
686. The scoping report for the Forthwind Offshore Wind Demonstration Project concluded, that due to the small scale of deployment, the industrial nature of the location and relatively low presence of marine mammals, impacts associated with vessel presence during the operation and maintenance phase (i.e. collision risk) were scoped out from further assessment (Cierco, 2019).
687. There is currently no information on the impacts the Cambois connection will have on marine mammal IEFs, although the Scoping Report have listed the types of vessels to be used during construction, including cable lay vessels, pre-lay survey vessels, rock protection vessels, support vessels, guard vessels, and possible use of jack-up vessels (SSER, 2022e). No details about the number of vessel round trips or type of vessels that will be used during operation and maintenance phase of were provided. However, risk of collision with vessels during the construction as well operation and maintenance phase cannot be discounted.
688. Due to lack of project information at this stage, it is not possible to undertake full, quantitative assessment for this impact and therefore a qualitative assessment is provided in paragraph 664 et seq.

Magnitude of impact

689. Vessel traffic associated with construction of the Proposed Development and construction as well as operation and maintenance of respective projects has the potential to lead to an increase in vessel movements, which could lead to an increase in interactions between marine mammals and vessels during offshore construction. However, vessel movements will be confined to the array areas and/or offshore cable routes and will follow existing shipping routes to/from port. As a result, the risk of collision to marine mammals is expected to be localised to within the boundaries of the respective projects. The types of vessels involved in construction activities at the other projects are expected to be similar to those identified for construction of the Proposed Development export cable corridor, such as jack-up vessels, tug/anchor handers, cable installation vessels, scour/cable protection installation vessel, guard vessels, survey vessels and CTVs. As previously described for the Proposed Development alone (see paragraph 404 et seq.), vessels travelling at 7 m/s or faster are those most likely to cause death or serious injury to marine mammals (Laist et al., 2001). Vessels involved in the construction phase of Proposed Development and respective projects are likely to be travelling considerably slower than this. There is also a potential that the noise emissions from vessels will deter animals from the potential zone of impact.
690. The cumulative impact of collision risk is predicted to be of local spatial extent, medium term duration, intermittent and low reversibility. It is predicted that the impact will affect the receptor directly. The magnitude is therefore considered to be low.

Sensitivity of receptor

691. The sensitivity of marine mammals to cumulative effects as a result of collision risk is as described in paragraph 668 et seq. for Tier 2 projects.
692. All marine mammals, which are IEFs of international value, are deemed to be of medium vulnerability and medium recoverability. The sensitivity of the receptor is therefore, considered to be medium.

Significance of effect

693. Overall, the magnitude of the cumulative impact is deemed to be low and the sensitivity of the receptor is considered to be medium. The cumulative effect will, therefore, be of minor adverse significance, which is not significant in EIA terms.

Further mitigation and residual effect

694. No secondary marine mammal mitigation is considered necessary as the predicted effect in the absence of further mitigation (beyond the designed in measures outlined in section 10.10) is not significant in EIA terms. Therefore, the residual effect is considered to be of minor adverse significance, which is not significant in EIA terms.

Operation and maintenance phase

695. The operation of the Proposed Development, together with Tier 3 projects identified in Table 10.55   Open ▸ may lead to cumulative effects as a result of collision risk. Projects screened into this assessment include the operation of Cambois connection and Forthwind Demonstration Project.
696. The scoping report for the Forthwind Offshore Wind Demonstration Project concluded, that due location, scale and nature of the development, operational effects such as collision risk were scoped out from further assessment (Cierco, 2019).
697. As presented in paragraph 643, there were no details about the number of vessel round trips or type of vessels that will be used during operation and maintenance phase of Cambois connection (SSER, 2022e). However, although currently there is no information on the impacts the Cambois connection will have on marine mammal IEFs, risk of collision with vessels during the operation and maintenance phase cannot be discounted.
698. Due to lack of detailed project information at this stage, it was not possible to undertake full, quantitative assessment for this impact and therefore a qualitative assessment is provided in paragraph 700 et seq.

Magnitude of impact

699. Given that vessel movements will be confined to the array areas and/or cable routes and will follow existing shipping routes to/from port, the risk of collision to marine mammals is expected to be largely localised to within the boundaries of the respective projects.
700. It is anticipated that the types of vessels involved in operation and maintenance activities at the other projects will be similar to those identified for the Proposed Development, such as vessels used during routine inspections, repairs and replacement of equipment, major component replacement, painting or other coatings, removal of marine growth and replacement of access ladders. The number of vessel movements during the operation and maintenance phase is likely to represent a slight increase in the risk of collision for marine mammals over the existing levels of vessel traffic. There is also a potential that the noise emissions from vessels will deter animals from the potential zone of impact.
701. Additionally, as presented in paragraph 679 it can be expected that after more than ten years of construction activities taking place in the vicinity of Firth of Forth, marine mammals present in the area will demonstrate some degree of habituation to the presence of high number of vessels. It is anticipated that the risk of collision at respective projects would be minimised through the adoption of factored in measures such as vessel codes of conduct as standard good practice for offshore wind developments. Therefore, even with a cumulative increase in vessel traffic, the type of vessels involved and transit routes is unlikely to impose a greater risk to marine mammals.
702. The cumulative impact is predicted to be of local spatial extent, long term duration, intermittent and effects are of low reversibility. It is predicted that the impact will affect the receptor directly. The magnitude is therefore considered to be low.

Sensitivity of receptor

703. The sensitivity of marine mammals to cumulative collision risk is as described for construction phase above in paragraph 692 et seq.
704. All marine mammals, which are IEFs of international value, are deemed to be of medium vulnerability and medium recoverability. The sensitivity of the receptor is therefore considered to be medium.

Significance of effect

705. Overall, the magnitude of the cumulative effect is deemed to be low and the sensitivity of the receptor is considered to be medium. The cumulative effect will, therefore, be of minor adverse significance, which is not significant in EIA terms.

Further mitigation and residual effect

706. No secondary marine mammal mitigation is considered necessary as the predicted effect in the absence of further mitigation (beyond the designed in measures outlined in section 10.10) is not significant in EIA terms. Therefore, the residual effect is considered to be of minor adverse significance, which is not significant in EIA terms.

Changes in fish and shellfish communities affecting prey availability

Tier 2

Construction phase

Magnitude of impact

707. The construction of the Proposed Development, together with the projects and plans identified in Table 10.54   Open ▸ , may lead to changes in the prey resources available for marine mammals as a result of changes to the fish and shellfish community. Potential cumulative impacts on marine mammal prey species during the construction phase have been assessed in volume 2, chapter 9 using the appropriate maximum design scenarios for these receptors. These impacts include temporary subtidal habitat loss/disturbance, long-term subtidal habitat loss, injury and/or disturbance to fish and shellfish from underwater noise and vibration and increased SSC and associated sediment deposition.
708. The construction phases and/or operation and maintenance phases of Inch Cape Offshore Wind Farm, Neart na Gaoithe Offshore Wind Farm, Seagreen 1, Seagreen 1A Project, Seagreen 1A Export Cable Corridor, Eyemouth disposal site, Eastern Link 1 and Eastern Link 2 may lead to cumulative temporary subtidal habitat loss/disturbance. The total cumulative temporary subtidal habitat loss is 142,813,855 m2 (=142.8 km2), however this number is highly conservative as the temporal overlap in construction activities between projects will be small and habitat loss associated operation and maintenance will be spread over the entirety of the phase, and therefore there will only be a small area of temporary habitat loss happening at any one time. As such, the magnitude of the impact has been assessed as low. Most fish and shellfish receptors found within the fish and shellfish ecology study area are deemed to be of low vulnerability, high recoverability and local to international importance and therefore sensitivity of the receptors was considered to be low to medium. Consequently, the cumulative effect of temporary habitat loss/disturbance was assessed as being of negligible to minor adverse significance.
709. The magnitude of long-term habitat loss caused by the presence of all structures on the seabed has been considered for the construction as well as operation and maintenance phases. The impacts have been assessed cumulatively with Inch Cape Offshore Wind Farm, Neart na Gaoithe Offshore Wind Farm, and Seagreen 1, Seagreen 1A Project, Seagreen 1A Export Cable Corridor and Eyemouth disposal site and may lead to long term subtidal habitat loss of up to 15,014,156 m2 (=15.0 km2). As the cumulative effect was predicted to be of local spatial extent, the magnitude has been assessed as low. Sensitivity of the fish and shellfish receptors was considered low to medium and the overall, cumulative effects were assessed as being of negligible to minor adverse significance.
710. The magnitude of impact on fish and shellfish receptors caused by the increase in SSC and associated deposition arising from the installation of wind turbines and OSPs/Offshore convertor station platform foundations, inter-array cables and offshore export cables during the construction phase has been assessed cumulatively with sea disposal of dredge material at the Eyemouth disposal site and installation of Inch Cape Offshore Wind Farm, Seagreen 1A Project, Eastern Link 1 and Eastern Link 2. Given that the magnitude of the cumulative effect has been determined ad low and sensitivity as low to medium, the cumulative effect of increased SSC and associated deposition was considered to be of negligible to minor adverse significance (see volume 2, chapter 9).
711. The potential for underwater noise and vibration during construction pile driving to result in injury and/or disturbance to fish and shellfish communities has been assessed cumulatively with Inch Cape Offshore Wind Farm and Seagreen 1A Project. Due to the application of soft start measures and small effect ranges, none of the projects predicted significant effects on fish and shellfish receptors. Given the limited duration of overlap in construction phases of the Proposed Development and aforementioned projects, the magnitude of effect has been considered as low. As sensitivity of the fish and shellfish IEF is low to minor, the overall cumulative effects were considered to be of negligible to minor adverse significance. With respect to indirect effects on marine mammals, no additional cumulative effects other than those assessed for injury and disturbance to marine mammals as a result of elevated underwater noise during piling (see paragraph 116 et seq.) are predicted. This is because if prey are disturbed from an area as a result of underwater noise, it is assumed that marine mammals are likely to be disturbed from the same or greater area, 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.
712. The cumulative impact is predicted to be of local spatial extent, medium term duration, intermittent and high reversibility. It is predicted that the impact will affect the receptor indirectly. The magnitude is therefore considered to be low.

Sensitivity of receptor

713. The sensitivity of marine mammals to changes in fish and shellfish communities affecting prey availability is as described in section 10.11, paragraph 440 et seq.
714. In the outer Firth of Forth area, sandeels are key prey items for harbour porpoise (Santos et al., 2004), minke whale (Robinson et al., 2007) and grey seal (Sparling, 2012). The cumulative assessment in volume 2, chapter 9 predicted that with respect to sandeel, given the minor temporal overlap in construction activities, impacts associated with temporal subtidal habitat disturbance will not add substantially to the total footprint associated with the Proposed Development. Subsequently, with wider sandeel habitat available within the regional marine mammal study area, projects considered in the cumulative assessment are not anticipated to affect foraging opportunities for sensitive marine mammal receptors.
715. The assessment for fish and shellfish IEFs concluded that significant cumulative effects on fish and shellfish communities are not anticipated (see volume 2, chapter 9). Marine mammals are known to forage over wide areas and exploit a range of prey species and whilst there may be some potential for cumulative effects to fish and shellfish communities due to multiple activities from relevant projects these effects will, for the most part, be highly localised and short term and therefore marine mammals are likely to be able to compensate and move to alternative foraging grounds.
716. All marine mammals, which are IEFs of international value, are deemed to be of low vulnerability and high recoverability. The sensitivity of the receptor is therefore considered to be low.

Significance of effect

717. Overall, the magnitude of the cumulative effect is deemed to be low and the sensitivity of the receptor is considered to be low. Given the extent of available foraging area in the regional marine mammal study area, the cumulative effect will, therefore, be of minor adverse significance, which is not significant in EIA terms.

Further mitigation and residual effect

718. No secondary marine mammal mitigation is considered necessary as the predicted effect in the absence of further mitigation (beyond the designed in measures outlined in section 10.10) is not significant in EIA terms. Therefore, the residual effect is considered to be of minor adverse significance, which is not significant in EIA terms.

Operation and maintenance phase

Magnitude of impact

719. The operation and maintenance activities of the cumulative projects (Inch Cape Offshore Wind Farm, Neart na Gaoithe Offshore Wind Farm, Seagreen 1, Seagreen 1A Project, Seagreen 1A Export Cable Corridor, Eastern Link 1, Eastern Link 2 and Eyemouth disposal site) will overlap with the operation and maintenance phase of the Proposed Development and may lead to temporary subtidal habitat loss/disturbance of up to 32,277,197 m2. Additionally, Offshore Wind Farms 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. The magnitude of the effect on fish and shellfish IEFs was assessed as low and the sensitivity of the receptors ranged from low to medium with the majority of fish receptors deemed to be of low vulnerability and high recoverability. Consequently, the cumulative effects of temporary habitat loss/disturbance on fish and shellfish IEFs during the operation and maintenance phase was assessed as being of negligible to minor adverse significance.
720. Cumulative 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 Corridor, Eastern Link 1 and Eastern Link 2. A total length of up to 6,170 km of subsea cabling was estimated for all projects. As the effect of EMF was predicted to be of local spatial extent, cumulatively, the magnitude was assessed as low. Sensitivity of the fish and shellfish receptors was considered to be low to medium and the overall, cumulative effects will be of negligible to minor adverse significance.
721. Artificial structures introduced into areas of predominantly soft sediments has the potential to alter community composition and biodiversity. There is a potential for cumulative 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 17,513,271 m2 of hard structures from wind turbines, OSPs/Offshore convertor station platforms, meteorological masts, of cable protection, and cable crossings. Given that the cumulative effect was predicted to be of local spatial extent, the magnitude was assessed as low. Sensitivity of the fish and shellfish receptors was considered to be low and the overall, cumulative effects will be of negligible to minor adverse significance. This is likely to be a conservative prediction as there is some evidence (although with uncertainties) that marine mammal populations are likely to benefit from introduction of hard substrates and associated fauna.
722. The cumulative impact is predicted to be of local spatial extent, long term duration, intermittent/continuous and the effect is of high reversibility. It is predicted that the impact will affect the receptor indirectly. The magnitude is therefore considered to be low.

Sensitivity of receptor

723. The sensitivity of marine mammals to cumulative changes in fish and shellfish communities affecting prey availability is as described in section 10.11, paragraph 714 et seq.
724. All marine mammals, which are IEFs of international value, are deemed to be of low vulnerability and high recoverability. The sensitivity of the receptor is therefore considered to be low.

Significance of effect

725. Overall, the magnitude of the cumulative impact is deemed to be low and the sensitivity of the receptor is considered to be low. Given the extent of available foraging area in the regional marine mammal study area, the cumulative effect will, therefore, be of minor adverse significance, which is not significant in EIA terms.

Further mitigation and residual effect

726. No secondary marine mammal mitigation is considered necessary as the predicted effect in the absence of further mitigation (beyond the designed in measures outlined in section 10.10) is not significant in EIA terms. Therefore, the residual effect is considered to be of minor adverse significance, which is not significant in EIA terms.

Tier 3

Construction phase

Magnitude of impact

727. The construction of the Proposed Development, together with the projects and plans identified in Table 10.54   Open ▸ , may lead to changes in the prey resources available for marine mammals as a result of changes to the fish and shellfish community. Potential cumulative impacts on marine mammal prey species during the construction phase have been assessed in volume 2, chapter 9 using the appropriate maximum design scenarios for these receptors.
728. The only Tier 3 project which has been identified in the CEA with the potential to result in cumulative temporary habitat loss with the Proposed Development is the Cambois connection. There is, however, currently no detailed information on the impact that these projects will have on fish and shellfish ecology IEFs and therefore it is not possible to undertake full, quantitative assessment for this impact.
729. The temporary subtidal habitat loss associated with Cambois connection assumes that 680 km of offshore export cables will be installed in trenches with a width of temporary ZoI of 25 m. The majority of this disturbance will not spatially overlap with the Proposed Development. Consequently, the cumulative effect of temporary habitat loss/disturbance for Tier 3 projects in volume 2, chapter 9 was assessed as being of minor adverse significance.
730. The predicted extent of long term habitat loss associated with this the Cambois connection Scoping Report (SSER, 2022e) is assumed to come from the installation of 102 km (15% of the total cable length) of cable protection with a width of 3 m in the form of rock/mattress protection.
731. The magnitude of impact on fish and shellfish receptors caused by the increase in SSC and associated deposition arising from the Cambois connection cable installation has been assessed as low (volume 2, chapter 9). The cumulative effect of increased SSC and associated deposition for Proposed Development and Tier 3 projects was considered to be of negligible to minor adverse significance.
732. The cumulative impact is predicted to be of local spatial extent, medium term duration, intermittent and high reversibility. It is predicted that the impact will affect the receptor indirectly. The magnitude is therefore considered to be low.

Sensitivity of receptor

733. The sensitivity of marine mammals to changes in fish and shellfish communities affecting prey availability is as described for Tier 2 projects in paragraph 714 et seq.
734. All marine mammals, which are IEFs of international value, are deemed to be of low vulnerability and high recoverability. The sensitivity of the receptor is therefore considered to be low.

Significance of effect

735. Overall, the magnitude of the cumulative effect is deemed to be low and the sensitivity of the receptor is considered to be low. Given the extent of available foraging area in the regional marine mammal study area, the cumulative effect will, therefore, be of minor adverse significance, which is not significant in EIA terms.

Further mitigation and residual effect

736. No secondary marine mammal mitigation is considered necessary as the predicted effect in the absence of further mitigation (beyond the designed in measures outlined in section 10.10) is not significant in EIA terms. Therefore, the residual effect is considered to be of minor adverse significance, which is not significant in EIA terms.

Operation and maintenance phase

Magnitude of impact

737. Cumulative impacts could arise from EMFs due to the presence of subsea cabling during the operation and maintenance phases of the Cambois connection. This project includes up to 680 km of cable therefore combining this with tier 2 projects and the Proposed Development would lead to a cumulative length of 5,568 km. The cumulative effect on fish and shellfish IEFs was predicted to be of negligible to minor adverse significance (volume 2, chapter 9).
738. Artificial structures introduced into areas of predominantly soft sediments has the potential to alter community composition and biodiversity. The Cambois connection has the potential to create 306,000 m2 of new hard habitat associated with rock/mattress cable protection which represents protection covering 15% the total length the four offshore export cables (volume 2, chapter 9). The cable protection represents a change in seabed type, however as the cable protection does not extend into the water column, the opportunity for colonisation by some species is reduced.
739. The cumulative impact is predicted to be of local spatial extent, long term duration, intermittent/continuous and the effect is of high reversibility. It is predicted that the impact will affect the receptor indirectly. The magnitude is therefore, considered to be low.

Sensitivity of receptor

740. The sensitivity of marine mammals to cumulative changes in fish and shellfish communities affecting prey availability is as described in section 10.11, paragraph 714 et seq.
741. All marine mammals, which are IEFs of international value, are deemed to be of low vulnerability and high recoverability. The sensitivity of the receptor is therefore considered to be low.

Significance of effect

742. Overall, the magnitude of the cumulative impact is deemed to be low and the sensitivity of the receptor is considered to be low. Given the extent of available foraging area in the regional marine mammal study area, the cumulative effect will, therefore, be of minor adverse significance, which is not significant in EIA terms.

Further mitigation and residual effect

743. No secondary marine mammal mitigation is considered necessary as the predicted effect in the absence of further mitigation (beyond the designed in measures outlined in section 10.10) is not significant in EIA terms. Therefore, the residual effect is considered to be of minor adverse significance, which is not significant in EIA terms.