Tier 2

Operation and maintenance phase only
Magnitude of impact
  1. There was one Tier 2 project identified within the 10 km buffer with potential for cumulative effects associated with this impact:
  • Morven BP-EnBW
  1. As outlined in paragraph 469 et seq., the impacts related to EMF are expected to be localised to within the close vicinity of the respective projects and transient for marine mammals and as such the assessment has focussed only on projects within a representative 10 km buffer of the Array as a proportionate approach.
  2. Whilst there is the potential for the operation and maintenance phase of Morven BP-EnBW to overlap with the operation and maintenance phase of the Array, the Morven Offshore Scoping Report did not include EMF as an impact for assessment on the basis of no likely effect on marine mammals, since fixed-foundation wind turbines lack suspended cables in the water column (Morven Offshore Wind Limited, 2023) and therefore there is no additional potential for cumulative effects for Tier 2 projects.
Sensitivity of the receptors
  1. The sensitivity of marine mammals to EMF is as describe for the Array, with detail given in section 10.11.2, paragraph 476 et seq.) and is not repeated here.
  2. All receptors, except humpback whale, are deemed to be of high resilience, high adaptability and recoverability and international value. The sensitivity of these receptors is therefore, considered to be low. Humpback whale is deemed to be of medium resilience and adaptability and high recoverability. The sensitivity of humpback whale is therefore, considered to be medium.
Significance of effect
  1. Overall, for all marine mammal species, the magnitude of the impact is deemed to be low and the sensitivity is considered to be low for all species except humpback whale, which is assessed as medium. Due to the uncertainty associated with the magnitude, the effect is assessed precautionarily as being of minor adverse significance, which is not significant in EIA terms.
Further mitigation and residual effect
  1. No marine mammal mitigation is considered necessary because the likely effect in the absence of further mitigation (beyond the designed in measures outlined in section 10.10) is not significant in EIA terms.

                        Tier 3

Operation and maintenance phase only
Magnitude of impact
  1. There was Tier 3 project identified within 10 km buffer with potential for cumulative effects associated with this impact:
  • Bellrock Offshore Wind Farm.
  1. Tier 3 projects are in a pre-application phase and no EIA Scoping Report or EIA Report is available to inform a quantitative assessment. Therefore, a qualitative assessment is provided below.
  2. As outlined in paragraph 599 et seq., the impacts related to EMF are expected to be localised and transient for marine mammals, expected to be localised to within the close vicinity of the respective projects and as such the assessment has focused only on projects within a representative 10 km buffer of the Array as a proportionate approach. Bellrock Offshore Wind Farm is the only project located within 10 km of the Array that has subsea cabling in the water column (Morven BP-EnBW Offshore Export Cable Corridor is buried), all other Tier 3 projects are located over 10 km away. The other Tier 3 projects which are located >10 km from the Array are considered to be located at a distance great enough that cumulative impacts are highly unlikely.
  3. At this point in time, Bellrock Offshore Wind Farm is anticipated to have impacts of EMF due to its floating design but no further information is currently available. Effects from EMF are expected to be highly localised to the projects, as described in paragraph 469 et seq. Moreover, the proposed capacity and spatial coverage of the Bellrock Offshore Wind Farm are both anticipated to be approximately one-third that of the Array (with Bellrock Offshore Wind Farm development area covering 280 km2).
  4. The cumulative impact is predicted to be of local spatial extent, long term duration, continuous and high reversibility. It is predicted that the impact will affect the receptor directly. The magnitude is therefore considered to be low.
Sensitivity of the receptors
  1. The sensitivity of marine mammals to EMF is as describe for the Array, with detail given in section 10.11.2, paragraph 476 et seq.) and is not repeated here.
  2. All receptors, except humpback whale, are deemed to be of high resilience, high adaptability and recoverability and international value. The sensitivity of these receptors is therefore, considered to be low. Humpback whale is deemed to be of medium resilience and adaptability and high recoverability. The sensitivity of humpback whale is therefore, considered to be medium.
Significance of effect
  1. Overall, for all marine mammal species, the magnitude of the impact is deemed to be low and the sensitivity is considered to be low for all species except humpback whale, which is assessed as medium. Due to the uncertainty associated with the magnitude, the effect is assessed precautionarily as being of minor adverse significance, which is not significant in EIA terms.
Further mitigation and residual effect
  1. No marine mammal mitigation is considered necessary because the likely effect in the absence of further mitigation (beyond the designed in measures outlined in section 10.10) is not significant in EIA terms.

Injury And Disturbance From Underwater noise Generated During The Operation Of Wind Turbines And Anchor Mooring Lines (Operation Phase)

  1. No Tier 1 projects with turbines (and therefore the potential for any cumulative operational noise) were identified within the 50 km buffer of the Array, and therefore there is no cumulative effect predicted from additional Tier 1 projects.

                        Tier 2

Operation and maintenance phase only
Magnitude of impact
  1. There was one Tier 2 project identified within 50 km buffer with potential for cumulative effects associated with this impact:
  2. Morven BP-EnBW. As outlined in paragraph 492 et seq. the impacts related to operational noise from turbines and anchor mooring lines are expected to be localised to within the close vicinity of the respective projects and as such the assessment has focussed only on projects within a representative 50 km buffer of the Array as a proportionate approach.
  3. Whilst there is the potential for the operation and maintenance phase of Morven BP-EnBW to overlap with the operation and maintenance phase of the Array, the Morven Offshore Scoping Report did not include operational noise as an impact for assessment (it has been scoped out in the Morven scoping report (Morven Offshore Wind Limited, 2023)) and therefore there is no additional potential for cumulative effects for Tier 2 projects.
Sensitivity of the receptors
  1. The sensitivity of marine mammals to operational noise from wind turbines and mooring lines is as described for the Array, with detail given in section 10.11.2, paragraph 496 et seq.) and is not repeated here.
  2. All receptors are deemed have limited resilience to auditory injury, low recoverability and adaptability and high international value. The sensitivity of the receptor to auditory injury is therefore, considered to be high.
Significance of effect
  1. Overall, the magnitude of the cumulative effect (auditory injury) is deemed to be negligible and the sensitivity of the receptor is considered to be high. The cumulative effect will, therefore, be of minor adverse significance, which is not significant in EIA terms.
  2. Overall, the magnitude of the effect (behavioural disturbance) is deemed to be negligible and the sensitivity of the receptor is considered to be medium. The effect will, therefore, be of minor adverse significance, which is not significant in EIA terms.
Further mitigation and residual effect
  1. No marine mammal mitigation is considered necessary because the likely effect in the absence of further mitigation (beyond the designed in measures outlined in section 10.10) is not significant in EIA terms.

 

                        Tier 3

Operation and maintenance phase
Magnitude of impact
  1. There were two Tier 3 projects identified with potential for cumulative effects associated with this impact:
  • Bellrock Offshore Wind Farm;
  • Bowdun Offshore Wind Farm; and
  • Campion.
  1. Tier 3 projects are in a pre-application phase and no EIA Scoping Report or EIA Report is available to inform a quantitative assessment. Therefore, a qualitative assessment is provided below.
  2. As described in paragraph 485 et seq., operational noise from anchor mooring lines is likely to be considerably lower compared to underwater noise associated with piling and UXO clearance activities that occurred during the construction phase. Most Tier 3 projects are located in excess of 50 km from the Array. The exceptions are Bellrock Offshore Wind Farm, Bowdun Offshore Wind Farm and Campion. Of these, only Bellrock and Campion are floating projects and may contribute to cumulative effects with respect to operational noise from anchor mooring lines.
  3. The Array alone assessment (see paragraph 485 et seq.), which draws on a study completed at a Hywind floating site in Scotland by Burns et al. (2022) concluded that the maximum distance at which the TTS could occur across all hearing groups was estimated for harbour porpoise at 50 m from a turbine assuming that the animal would remain stationary for the 24 hour period (Burns et al., 2022). The study concluded that even at a wind speed of 25 knots, the noise footprint is negligible and in the relatively noisy soundscape of the North Sea, it does not present any realistic threat of auditory injury to marine species. Similarly, the impact from the Array alone was considered to be negligible. As discussed in paragraph 489, Risch et al. (2023a) found noise emissions from FOW turbines were similar to the operational noise of fixed offshore wind turbines, with biggest difference between fixed and FOW turbines in relation to underwater noise generation is mooring-related noise, rather the operational wind turbine noise.
  4. Considering Bellrock Offshore Wind Farm, Bowdun Offshore Wind Farm and Campion are ~8 km, ~25 km~44 km from the Array, respectively and on the basis of the estimated TTS ranges associated with operational noise the potential for a cumulative impact is unlikely.
  5. For auditory injury, the cumulative impact is predicted to be of local spatial extent, long term duration, continuous and high reversibility (the elevation in underwater sound occurs only during the operation and maintenance phases). The injury, which is highly unlikely to occur, would be of medium (TTS) to low (PTS) reversibility. It is predicted that the impact will affect the receptor directly. Given that animals are highly unlikely to stay within the injury ranges continuously for 24 hours, injury and therefore population-level effects are highly unlikely to occur. The magnitude for injury is therefore considered to be negligible.
  6. For behavioural disturbance, the impact (elevated underwater noise from floating wind turbines and mooring lines) is predicted to be of local spatial extent, long term duration and continuous. The impact as well as the effect of behavioural disturbance are of high reversibility. It is predicted that the impact will affect the receptor directly. Although noise levels are likely to be audible to marine mammals, animals are unlikely to experience behavioural disturbance including displacement as a result of the increased underwater noise during operational phase. The magnitude is therefore considered to be negligible.
Sensitivity of the receptors
  1. The sensitivity of marine mammals to operational noise from wind turbines and mooring lines is as described for the Array, with detail given in section 10.11.2, paragraph 496 et seq.) and is not repeated here.
  2. All receptors are deemed have limited resilience to auditory injury, low recoverability and adaptability and high international value. The sensitivity of the receptor to auditory injury is therefore, considered to be high.
  3. All receptors are deemed to have some resilience to behavioural disturbance, high recoverability and adaptability and high international value. The sensitivity of the receptor to behavioural disturbance is therefore, considered to be medium.
Significance of effect
  1. Overall, the magnitude of the cumulative effect (auditory injury) is deemed to be negligible and the sensitivity of the receptor is considered to be high. The cumulative effect will, therefore, be of minor adverse significance, which is not significant in EIA terms.
  2. Overall, the magnitude of the effect (behavioural disturbance) is deemed to be negligible and the sensitivity of the receptor is considered to be medium. The effect will, therefore, be of minor adverse significance, which is not significant in EIA terms.
Further mitigation and residual effect
  1. No marine mammal mitigation is considered necessary because the likely effect in the absence of further mitigation (beyond the designed in measures outlined in section 10.10) is not significant in EIA terms.

Effects on marine mammals due to entanglement

  1. There are concerns regarding the hazards that mooring lines and dynamic cables may pose to marine mammals, which could inadvertently become entangled or entrapped (MD-LOT, 2023). The expansion in FOW means there is an increasing cumulative risk of entanglement.
  2. However, no Tier 1 or Tier 2 projects were identified with the potential for entanglement risk (i.e. FOW projects) within the 50 km buffer region.

                        Tier 3

Operation and maintenance phase
Magnitude of impact
  1. There were two Tier 3 FOW projects identified within the 50 km buffer region with potential for cumulative effects associated with this impact:
  • Bellrock Offshore Wind Farm; and
  • Campion.
  1. Tier 3 projects are in a pre-application phase and no EIA Scoping Report or EIA Report is available to inform a quantitative assessment. Therefore, a qualitative assessment is provided below.
  2. As described in paragraph 520, as a part of the designed in measures, mooring lines and dynamic inter-array cables will undergo regular inspections during the operation and maintenance phase, employing a risk-based adaptive management approach. All Tier 3 projects are located in excess of 50 km from the Array except for Bellrock, Bowdun and Campion Offshore Wind Farms. Of these projects only Bellrock and Campion are floating projects and may contribute to the cumulative impacts of entanglement.
  3. The risks of entanglement are not fully understood but the commitment of the Array to monitor and manage the risks will reduce any potential contribution to cumulative effects with other projects. There are no published standard industry measures at the time of writing, but should other wind projects adopt a similar 'monitor and manage' approach, it is likely that the potential for cumulative effects would be further reduced. Considering the implementation of these designed in measures during the operation and maintenance phases of the Array, the potential for contribution of the Array to any cumulative effects resulting from entanglement is considered very unlikely.
  4. The impact (risk of entanglement due to presence of mooring lines and inter-array cables in the water column) is predicted to be of very local spatial extent in the context of the geographic frame of reference, long term duration, continuous and the effect is irreversible when entanglement does occur. It is predicted that the impact will affect the receptor directly in the case of both (rare) primary entanglement and secondary entanglement, however the risk of secondary entanglement is sufficiently reduced with the application of the designed in measures (routine surveys and removal of marine debris as required following inspection) and any population-level effects are highly unlikely and the project will reduce any contribution to cumulative effects. Therefore, the magnitude of primary and secondary entanglement is considered to be low.
Sensitivity of the receptors
  1. The sensitivity of marine mammals to entanglement is as described for the Array, with detail given in section 10.11.2, paragraph 524 to 530 for primary entanglement and 534 to 545 for secondary entanglement) and is not repeated here.

Primary entanglement

  1. Mysticetes are deemed to have some resilience to primary entanglement (largely due to avoidance and design of mooring lines/cables), some adaptability, limited recoverability and are of international value. The sensitivity of the receptors (minke whale and humpback whale) is therefore, conservatively, considered to be medium.
  2. Odontocetes and pinnipeds are deemed to have some resilience to primary entanglement (largely due to avoidance and design of mooring lines/cables), high adaptability, limited recoverability and are of international value. The sensitivity of the receptors (harbour porpoise, bottlenose dolphin, white-beaked dolphin and grey seal) is therefore, considered to be low.

Secondary entanglement

  1. Marine mammals are deemed to have some resilience to secondary entanglement (largely via avoidance), medium adaptability, limited recoverability and are of international value. The designed in measures (routine inspections and removal of marine debris as required) will reduce the risks for secondary entanglement, but due to paucity of information on secondary entanglement and the irreversible nature if entanglement does occur, the sensitivity of all marine mammals is conservatively considered to be medium.

 

Significance of effect

Primary entanglement
  1. Overall, the magnitude of the cumulative impact (primary entanglement) is deemed to be low for all marine mammals and the sensitivity of the receptor is considered to be low for odontocetes and pinnipeds and medium for mysticetes. the cumulative effect therefore will be of minor adverse significance for all species, which is not significant in EIA terms.
Secondary entanglement
  1. Overall, the magnitude of the cumulative impact (secondary entanglement) is deemed to be low for all marine mammals and the sensitivity of all receptors (odontocetes, pinnipeds and mysticetes) is considered to be low. The cumulative effect will, therefore, be of minor adverse significance for all marine mammals, which is not significant in EIA terms.

Further mitigation and residual effect

  1. No marine mammal mitigation is considered necessary because the likely effect in the absence of further mitigation (beyond the designed in measures outlined in section 10.10) is not significant in EIA terms.

Effects On Marine Mammals Due To Altered Prey Availability

                        Tier 1

Construction phase
Magnitude of impact
  1. The construction of the Array together with the projects and plans identified in Table 10.52   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 MDSs for these receptors and therefore are carried forward here. Key impacts include temporary habitat loss/disturbance, long term habitat loss/disturbance and underwater noise from piling and UXO clearance impacting fish and shellfish receptors.
  2. There is potential for cumulative temporary habitat loss and disturbance impacting fish and shellfish receptors because of construction activities associated with the Array and the other plans and projects, and volume 2, chapter 9 identified one Tier 1 project with potential for CEA effects for this impact: the Proposed offshore export cable corridor(s). The maximum duration of the offshore construction phase for the Array is up to seven years and therefore, there may be five years of overlap between the site preparation and construction activities of the Array and the Proposed offshore export cable corridor(s). Within this phase of development of the Array, site preparation and construction activities are anticipated to occur intermittently; activities will be spread across the phase with only a small proportion of the MDS footprint for this impact being affected at any one time. As the cumulative effect was predicted to be of local spatial extent, medium duration and high reversibility, the magnitude has been assessed as low (in volume 2, chapter 9). Sensitivity of the fish and shellfish receptors was considered low to medium and overall, cumulative effects were assessed as being of minor adverse significance fish and shellfish IEFs.
  3. There is potential for cumulative long term habitat loss and disturbance impacting fish and shellfish receptors. Volume 2, chapter 9 identified two Tier 1 projects with potential for CEA effects for this impact: the Proposed offshore export cable corridor(s) and the Eastern Green Link (operation and maintenance phase). It likely that long term habitat loss will occur at the Tier 1 projects because of cable and/or pipeline protection and crossing protection, and presents some measurable, but minor, long term loss of and alteration to the affected areas of seabed within the Array fish and shellfish ecology study area and wider North Sea. As the cumulative effect was predicted to be of local spatial extent, the magnitude has been assessed as low (in volume 2, chapter 9). Sensitivity of the fish and shellfish receptors was considered low to medium and therefore overall, cumulative effects were assessed as being of minor adverse significance for all fish and shellfish IEFs.
  4. There is potential for cumulative effects from underwater noise from piling and UXO clearance impacting fish and shellfish receptors. Volume 2, chapter 9 identified two Tier 1 projects with potential for CEA effects for this impact: the Proposed offshore export cable corridor(s) and Berwick Bank Offshore Wind Farm. As the cumulative effect was predicted to be of regional spatial extent, medium duration and high reversibility, the magnitude has been assessed as low (in volume 2, chapter 9). Sensitivity of the fish and shellfish receptors was considered low to medium (herring) and therefore overall, cumulative effects were assessed as being of minor adverse significance for all fish and shellfish IEFs.
  5. With respect to indirect effects on marine mammals, no additional cumulative effects due to changes in prey availability are predicted (with no significant cumulative effects predicted for fish and shellfish IEFs). As discussed in paragraph 559, all marine mammals in this assessment are considered to be generalist opportunistic feeders and are thus not reliant on a single prey species. Given that marine mammals are wide-ranging in nature with the ability to exploit numerous food sources, there would be a variety of prey species available for marine mammal foraging.
  6. The impact of altered prey availability on marine mammals is predicted to be of local spatial extent, medium term duration, intermittent and the effect on marine mammals is of high reversibility. Therefore, cumulatively for marine mammals, the impact of effects on marine mammals due to altered prey availability is low.
Sensitivity of the receptors
  1. The sensitivity of marine mammals altered prey availability is as described for the Array, with detail given in paragraph 560 to 565 and is not repeated here.
  2. All receptors are deemed to be of high resilience, high recoverability and adaptability and high international value. The sensitivity of the receptor is therefore, considered to be low.
Significance of effect
  1. Overall, the magnitude of the impact is deemed to be low and the sensitivity of the receptor is considered to be low. The effect will, therefore, be of minor adverse (though could be minor beneficial for some species dependent on the reef effect) significance, which is not significant in EIA terms.
Further mitigation and residual effect
  1. No marine mammal mitigation is considered necessary because the likely effect in the absence of further mitigation (beyond the designed in measures outlined in section 10.10) is not significant in EIA terms.
Operation and maintenance phase
Magnitude of impact
  1. Potential cumulative impacts on marine mammal prey species during the operation and maintenance phase have been assessed in volume 2, chapter 9 using the appropriate MDSs for these receptors and therefore are carried forward here.
  2. There is potential for cumulative temporary habitat loss and disturbance because of activities associated with the Array and the other plans and projects, and volume 2, chapter 9 identified two Tier 1 projects with potential for CEA effects for this impact: the Proposed offshore export cable corridor(s) and Eastern Green Link 2. The operation and maintenance phase of Eastern Green Link 2 and Proposed offshore export cable corridor(s) overlaps temporally with that of the Array. As the cumulative effect was predicted to be of local spatial extent, the magnitude for cumulative temporary habitat loss and disturbance has been assessed as negligible (in volume 2, chapter 9). Sensitivity of the fish and shellfish receptors was considered low to medium and overall, cumulative effects from temporary habitat loss and disturbance were assessed as being of minor adverse significance.
  3. Volume 2, chapter 9 combined the cumulative assessment for all phases for the impact of long term habitat loss and disturbance and therefore the magnitude of impact is as described in paragraph 995 and is not duplicated here.
  4. There is potential for cumulative effects to fish and shellfish receptors due to EMF from subsea electrical cabling, and volume 2, chapter 9 identified the Proposed offshore export cable corridor(s) and Eastern Green Link 2 for cumulative effects associated with EMF. EMF levels in the vicinity of subsea cables are influenced by a variety of design and installation factors, including distance between cables, cable sheathing, number of conductors, and internal cable configuration. Further, the intensity of EMF from subsea cables decreases at approximately the inverse square/power of the distance away from the cable (Hutchison et al., 2021). This attenuation is the same for buried, unburied, and dynamic cables (Hutchison et al., 2021). Therefore, the cumulative magnitude of impact with the Tier 1 projects is likely to be highly localised to within metres to tens of metres from cables. For all fish and shellfish IEF species, including those key prey species for marine mammals, the cumulative magnitude of the impact is deemed to be low and the sensitivity of the receptor is considered to be low. The effect will, therefore, be of negligible to minor adverse significance, which is not significant in EIA terms.
  5. There is potential for cumulative effects to fish and shellfish receptors from colonisation of hard substrates. Volume 2, chapter 9 identified two Tier 1 projects with potential for CEA effects for this impact: the Proposed offshore export cable corridor(s) and the Eastern Green Link (operation and maintenance phase). A detailed CEA assessment is given in volume 2, chapter 9 which determined that the cumulative spatial extent of this impact in the operation and maintenance phase is likely to be small in relation to the whole Array fish and shellfish ecology study area. It is expected that these artificial hard substrates will be colonised by epifaunal species local to the Array fish and shellfish ecology study area, but this impact will represent a shift in the baseline seabed conditions from soft to hard substrate in the areas where the infrastructure is installed. This could result in beneficial effects for fish and shellfish IEFs (e.g. increased biodiversity, greater shelter/protection opportunities, greater prey availabilities and potential reef effects (Bender et al., 2020, Langhamer et al., 2016)), but could also reduce burial substrate for species like edible crab (which do not form a major prey species for marine mammal IEFs). As the cumulative effect was predicted to be of local spatial extent but long term duration, the magnitude has been assessed as low (in volume 2, chapter 9). Sensitivity of the fish and shellfish receptors was considered low to medium and therefore overall, cumulative effects were assessed as being of negligible (considering any potential beneficial effects) to minor adverse significance for all fish and shellfish IEFs.
  6. As discussed in paragraph 559 et seq. all marine mammals in this assessment are considered to be generalist opportunistic feeders and are thus not reliant on a single prey species. Given that marine mammals are wide-ranging in nature with the ability to exploit numerous food sources, there would be a variety of prey species available for marine mammal foraging.
  7. Therefore, cumulatively for marine mammals, the impact of effects on marine mammals due to altered prey availability is predicted to be of local spatial extent, long term duration, intermittent and the effect on marine mammals is of high reversibility. The magnitude for effects on marine mammals due to altered prey availability is therefore, considered to be low.
Sensitivity of the receptors
  1. The sensitivity of marine mammals altered prey availability is as described for the Array, with detail given in paragraph 560 to 565 and is not repeated here.
  2. All receptors are deemed to be of high resilience, high recoverability and adaptability and high international value. The sensitivity of the receptor is therefore, considered to be low.
Significance of effect
  1. Overall, the magnitude of the cumulative impact is deemed to be low and the sensitivity of the receptor is considered to be low. The effect will, therefore, be of minor adverse/beneficial significance, which is not significant in EIA terms.
Further mitigation and residual effect
  1. No marine mammal mitigation is considered necessary because the likely effect in the absence of further mitigation (beyond the designed in measures outlined in section 10.10) is not significant in EIA terms.
Decommissioning phase
Magnitude of impact
  1. Volume 2, chapter 9 combined the cumulative assessment for all phases for the impact of long term habitat loss and disturbance and therefore the magnitude of impact is as described in paragraph 995.
  2. Volume 2, chapter 9 combined the cumulative assessment for all phases for the impact of colonisation of hard structures and therefore the magnitude of impact is as described in paragraph 1022.
  3. Volume 2, chapter 9 did not assess the impact of temporary habitat loss during the decommissioning phase as there is not sufficient information to determine the decommissioning programme of plans/projects screened into the CEA. However, the magnitude of impact is likely to be similar to, or less than, the cumulative effect of construction.
Sensitivity of the receptors
  1. The sensitivity of marine mammals altered prey availability is as described for the Array, with detail given in paragraph 560 to 565 and is not repeated here.
  2. All receptors are deemed to be of high resilience, high recoverability and adaptability and high international value. The sensitivity of the receptor is therefore, considered to be low.
Significance of effect
  1. Overall, the magnitude of the impact is deemed to be low and the sensitivity of the receptor is considered to be low. The effect will, therefore, be of minor adverse (though could be minor beneficial for some species dependent on the reef effect) significance, which is not significant in EIA terms.
Further mitigation and residual effect
  1. No marine mammal mitigation is considered necessary because the likely effect in the absence of further mitigation (beyond the designed in measures outlined in section 10.10) is not significant in EIA terms.

                        Tier 2

Construction phase
Magnitude of impact
  1. The construction of the Array together with the projects and plans identified in Table 10.52   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 MDSs for these receptors and therefore are carried forward here.
  2. In addition to the Tier 1 projects, there was one Tier 2 project identified in volume 2, chapter 9 with potential for cumulative LSE1 associated with temporary habitat loss and disturbance in the construction phase: the operation and maintenance and decommissioning phases of Morven BP-EnBW. According to the Morven BP-EnBW Scoping Report (Morven Offshore Wind Limited, 2023), site preparation and construction activities applicable to this impact for Morven BP-EnBW are expected to be site preparation (sand wave clearance and boulder clearance and relocation) cable installation; and jack-up vessel use for infrastructure installation (Morven Offshore Wind Limited, 2023). Given the reversibility of temporary habitat loss and disturbance, and the fact that construction operations would only affect a small proportion of the total habitat loss and disturbance footprint at any one time any, the cumulative magnitude of impact is still not expected to represent additional material impact because it represents only a small proportion of the habitats within the fish and shellfish ecology study area and the wider North Sea area. For most marine and shellfish species, the cumulative magnitude of the impact is deemed to be low and the sensitivity of most fish IEFs (including herring) is considered to be low. The effect will, therefore, be of minor adverse significance, which is not significant in EIA terms. For sandeel, the cumulative magnitude of the impact is deemed to be low and the sensitivity is considered to be medium. The effect will, therefore, be of minor adverse significance which is not significant in EIA terms. This is largely due to the area of unsuitable habitat for sandeel, that sandeel spawning grounds within the fish and shellfish ecology area is of low intensity and because modelling shows the abundance of buried sandeel to be very low.
  3. In addition to the Tier 1 projects, there was one Tier 2 project identified in volume 2, chapter 9 with potential for cumulative effects associated with long term habitat loss and disturbance in the construction phase: the operation and maintenance and decommissioning phases of Morven BP-EnBW. According to the Morven BP-EnBW Scoping Report, infrastructure associated with long term habitat loss and disturbance is expected to include foundations, scour protection, cable protection, and cable crossing protection, although further detail on extents and footprints was not provided in the Scoping Report for Morven BP-EnBW (Morven Offshore Wind Limited, 2023). Volume 2, chapter 9 stated the cumulative magnitude of impact is still not expected to represent significant additional impact than that defined for the assessment of the Array alone because it represents only a small proportion of the habitats within the fish and shellfish ecology study area and the wider North Sea area. For most fish and shellfish IEF species (including herring), the cumulative magnitude of the impact is deemed to be low and the sensitivity of the receptor is considered to be low. The effect will, therefore, be of minor adverse significance, which is not significant in EIA terms. For sandeel (an important prey species for minke whale), the cumulative magnitude of the impact is deemed to be low and the sensitivity of the receptor is considered to be medium. The effect will, therefore, be of minor adverse significance, which is not significant in EIA terms.
  4. As discussed in paragraph 559 et seq. all marine mammals in this assessment are considered to be generalist opportunistic feeders and are thus not reliant on a single prey species. Given that marine mammals are wide-ranging in nature with the ability to exploit numerous food sources, there would be a variety of prey species available for marine mammal foraging.
  5. Therefore, cumulatively for marine mammals, the impact of effects on marine mammals due to altered prey availability is predicted to be of local spatial extent, medium term duration, intermittent and the effect on marine mammals is of high reversibility. The magnitude for effects on marine mammals due to altered prey availability is therefore, considered to be low.
Sensitivity of the receptors
  1. The sensitivity of marine mammals altered prey availability is as described for the Array, with detail given in paragraph 560 to 565 and is not repeated here.
  2. All receptors are deemed to be of high resilience, high recoverability and adaptability and high international value. The sensitivity of the receptor is therefore, considered to be low.
Significance of effect
  1. Overall, the magnitude of the cumulative impact is deemed to be low and the sensitivity of the receptor is considered to be low. The effect will, therefore, be of minor adverse/beneficial significance, which is not significant in EIA terms.
Further mitigation and residual effect
  1. No marine mammal mitigation is considered necessary because the likely effect in the absence of further mitigation (beyond the designed in measures outlined in section 10.10) is not significant in EIA terms.
Operation and maintenance phase
Magnitude of impact
  1. The construction of the Array together with the projects and plans identified in Table 10.52   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 operation and maintenance phase have been assessed in volume 2, chapter 9 using the appropriate MDSs for these receptors and therefore are carried forward here.
  2. In addition to the Tier 1 projects, there was one Tier 2 project identified in volume 2, chapter 9 with potential for cumulative effects during the operation and maintenance phase associated with temporary habitat loss and disturbance: the operation and maintenance phases of the Morven BP-EnBW. As with the Array, operation and maintenance activities applicable to this impact for the Morven BP-EnBW are expected to include cable repair and reburial and the use of jack-up vessels for operation and maintenance activities (Morven Offshore Wind Limited, 2023). Within the Scoping Report for Morven BP-EnBW, it is stated that the extent of these activities is expected to be lower than that of the site preparation and construction phase (Morven Offshore Wind Limited, 2023). The cumulative magnitude of impact of the Tier 2 assessment presented in volume 2, chapter 9 is not expected to represent additional material impact beyond that defined for the assessment of the Array alone. For marine and shellfish species, the cumulative magnitude of the impact is deemed to be low and the sensitivity of most fish IEFs (including herring) is considered to be low. The effect will, therefore, be of minor adverse significance, which is not significant in EIA terms. For sandeel, the cumulative magnitude of the impact is deemed to be low and the sensitivity is considered to be medium. The effect will, therefore, be of minor adverse significance which is not significant in EIA terms. This is largely due to the area of unsuitable habitat for sandeel, that sandeel spawning grounds within the fish and shellfish ecology area is of low intensity and because modelling shows the abundance of buried sandeel to be very low. For diadromous species, the cumulative magnitude of the impact is deemed to be low and the sensitivity of the receptor is considered to be low. The effect will, therefore, be of minor adverse significance, which is not significant in EIA terms.
  3. Volume 2, chapter 9 combined the cumulative assessment for construction and operation and maintenance phases for the impact of long term habitat loss and disturbance and therefore the magnitude of impact is as described in paragraph 1023.
  4. In addition to the Tier 1 projects, there was one Tier 2 project identified in volume 2, chapter 9 with potential for cumulative effects associated with colonisation of hard structures in the construction phase: the operation and maintenance and decommissioning phases of Morven Offshore Wind Farm. According to the Morven BP-EnBW Scoping Report, hard structures installed at the Morven BP-EnBW are expected to include foundations, scour protection, and cable protection (Morven Offshore Wind Limited, 2023). As per the Tier 1 assessment, it is expected that the hard structures will be colonised by local epifauna, but will still represent a shift in the baseline conditions from soft sediments to hard substrate, which could be beneficial for some fish and shellfish receptors (Bender et al., 2020, Langhamer et al., 2016). Some fish species may benefit from the colonisation of hard structures, whereas others (more likely to be less mobile, demersal species) may be adversely affected. Overall, for fish and shellfish, the cumulative magnitude of the impact is deemed to be low and the sensitivity of the receptor is considered to be low. At worst, the effect will, therefore, be of negligible to minor adverse significance, which is not significant in EIA terms, though could be minor beneficial for some species. This is likely to be a conservative prediction as there is some evidence (although with uncertainties) that some fish and shellfish populations are likely to benefit from introduction of hard structures. For diadromous fish, the cumulative magnitude of the impact is deemed to be low and the sensitivity of the receptor is considered to be low. The effect will, therefore, be of negligible to minor adverse significance, which is not significant in EIA terms.

 

  1. In addition to the Tier 1 projects, there was one Tier 2 project identified in volume 2, chapter 9 with potential for cumulative effects associated with EMF: the operation and maintenance phase of Morven BP-EnBW. As for Tier 1 projects, EMF levels in the vicinity of subsea cables are influenced by a variety of design and installation factors, including distance between cables, cable sheathing, number of conductors, and internal cable configuration. Further, the intensity of EMF from subsea cables decreases at approximately the inverse square/power of the distance away from the cable (Hutchison et al., 2021). This attenuation is the same for buried, unburied, and dynamic cables (Hutchison et al., 2021). Therefore, volume 2, chapter 9 concluded the cumulative magnitude of impact with the Tier 2 projects is likely to be highly localised to within metres to tens of metres from cables. For all fish and shellfish IEF species, the cumulative magnitude of the impact is deemed to be low and the sensitivity of the receptor is considered to be low. The effect will, therefore, be of negligible to minor adverse significance, which is not significant in EIA terms.
  2. As discussed in paragraph 559 et seq. all marine mammals in this assessment are considered to be generalist opportunistic feeders and are thus not reliant on a single prey species. Given that marine mammals are wide-ranging in nature with the ability to exploit numerous food sources, there would be a variety of prey species available for marine mammal foraging.
  3. Therefore, cumulatively for marine mammals, the impact of effects on marine mammals due to altered prey availability is predicted to be of local spatial extent, long term duration, intermittent and the effect on marine mammals is of high reversibility. The magnitude for effects on marine mammals due to altered prey availability is therefore, considered to be low.
Sensitivity of the receptors
  1. The sensitivity of marine mammals altered prey availability is as described for the Array, with detail given in paragraph 560 to 565 and is not repeated here.
  2. All receptors are deemed to be of high resilience, high recoverability and adaptability and high international value. The sensitivity of the receptor is therefore, considered to be low.
Significance of effect
  1. Overall, the magnitude of the cumulative impact is deemed to be low and the sensitivity of the receptor is considered to be low. The effect will, therefore, be of minor adverse/beneficial significance, which is not significant in EIA terms.
Further mitigation and residual effect
  1. No marine mammal mitigation is considered necessary because the likely effect in the absence of further mitigation (beyond the designed in measures outlined in section 10.10) is not significant in EIA terms.
Decommissioning phase
  1. Volume 2, chapter 9 did not assess decommissioning cumulatively and therefore it is not considered further in this CEA assessment. However, it is likely that the cumulative effects will be less than those from the construction and operational phase, and it is likely that over the lifetime of relevant projects marine mammals will have adapted to available prey sources.

                        Tier 3

Construction phase
Magnitude of impact
  1. The construction of the Array together with the projects and plans identified in Table 10.52   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 MDSs for these receptors and therefore are carried forward here.
  2. Volume 2, chapter 9 identified six Tier 3 projects with potential for cumulative effects associated with this temporary habitat loss in the construction phase: Bellrock Offshore Wind Farm, Bowdun Offshore Wind Farm, Campion Offshore Wind Farm, Eastern Green Link 3, Eastern Green Link 4 and Morven Offshore Export Cable Corridor. As these are Tier 3 projects, there are no Scoping Reports or EIA documents in the public domain. Therefore, there is no information available on the impact that these Tier 3 projects will have on fish and shellfish ecology. Temporary habitat loss and disturbance impacts associated with the Bellrock Offshore Wind Farm, Bowdun Offshore Wind Farm and Campion Offshore Wind Farm are expected to be similar in nature and extent to the Array. Impacts associated with the Morven Offshore Export Cable Corridor and Eastern Green Link 3 and 4 are likely to be similar to those assessed in Tier 1 for the Proposed offshore export cable corridor(s) and Eastern Green Link 2. The maximum duration of the offshore construction phase for the Array is up to seven years (2031 to 2038). There are currently no dates available for the construction phase of Bowdun Offshore Wind farm, Campion Offshore Wind farm and various INTOG projects. Therefore, there may be minimal overlap between the site preparation and construction activities of the Array and that of the Tier 3 projects. Volume 2, chapter 9 concluded for marine and shellfish species, the cumulative magnitude of the impact is deemed to be low and the sensitivity of most fish IEFs (including herring) is considered to be low. The effect will, therefore, be of minor adverse significance, which is not significant in EIA terms. For sandeel, the cumulative magnitude of the impact is deemed to be low, and the sensitivity is considered to be medium. The effect will, therefore, be of minor adverse significance which is not significant in EIA terms. This is largely due to the area of unsuitable habitat for sandeel, that sandeel spawning grounds within the fish and shellfish ecology area is of low intensity and because modelling shows the abundance of buried sandeel to be very low. For diadromous species, the cumulative magnitude of the impact is deemed to be low and the sensitivity of the receptor is considered to be low. The effect will, therefore, be of minor adverse significance, which is not significant in EIA terms.
  3. Long term habitat loss and disturbance impacts associated with Bellrock Offshore Wind farm, Bowdun Offshore Wind farm and Campion Offshore Wind Farm are expected to be similar in nature and extent to the Array, with the exception of the fixed foundations at Bowdun Offshore Wind farm, of which the extent of habitat loss is not possible to quantify at this stage. The impacts of site preparation and construction and operation and maintenance activities are expected to be long term and reversible. Volume 2, chapter 9 concluded for most fish and shellfish IEF species (including herring), the cumulative magnitude of the impact is deemed to be low and the sensitivity of the receptor is considered to be low. The effect will, therefore, be of minor adverse significance, which is not significant in EIA terms. For sandeel, the cumulative magnitude of the impact is deemed to be low and the sensitivity of the receptor is considered to be medium. The effect will, therefore, be of minor adverse significance, which is not significant in EIA terms. For diadromous species, the cumulative magnitude of the impact is deemed to be low and the sensitivity of the receptor is considered to be low. The effect will, therefore, be of minor adverse significance, which is not significant in EIA terms.
  4. Volume 2, chapter 9 identified addition to the Tier 1 and Tier 2 projects, seven Tier 3 projects with potential for cumulative effects associated with underwater noise impacting fish and shellfish receptors: Morven Offshore Export Cable Corridor(s), Bellrock Offshore Wind Farm, Bowdun Offshore Wind farm, Campion Offshore Wind Farm, unknown phases of INTOG 10, Flora Floating Wind Farm, and Aspen. As these are Tier 3 projects, there are no Scoping reports or EIA documents in the public domain. Therefore, there is no information available on the impact that these Tier 3 projects will have on fish and shellfish ecology, though piling activities during the construction phase are expected to be similar in nature as that of the Array. Although information on hammer energies and piling durations are not available for Bowdun Offshore Wind Farm and Campion Offshore Wind Farm, the impact is likely to be of medium term duration, with noise being intermittent during the construction phase. volume 2, chapter 9 identified there may be minimal overlap between the site preparation and construction activities of the Array and that of the Tier 3 projects. For most marine fish, diadromous fish, and shellfish, the cumulative magnitude of the impact is deemed to be low, and the sensitivity of most marine fish IEFs is considered low. The effect will, therefore, be of minor adverse significance, which is not significant in EIA terms. For herring, the cumulative magnitude of the impact is deemed to be low, and the sensitivity of herring is considered to be medium. The effect will, therefore, be of minor adverse significance, which is not significant in EIA terms.
  5. As discussed in paragraph 559 et seq. all marine mammals in this assessment are considered to be generalist opportunistic feeders and are thus not reliant on a single prey species. Given that marine mammals are wide-ranging in nature with the ability to exploit numerous food sources, there would be a variety of prey species available for marine mammal foraging.
  6. Therefore, cumulatively for marine mammals, the impact of effects on marine mammals due to altered prey availability is predicted to be of local spatial extent, medium term duration, intermittent and the effect on marine mammals is of high reversibility. The magnitude for effects on marine mammals due to altered prey availability is therefore, considered to be low.