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 operation and maintenance 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 and Tier 2 projects, volume 2, chapter 9 identified six Tier 3 projects with potential for cumulative effects associated with temporary habitat loss and disturbance during the operation and maintenance phase: Morven Offshore Export Cable Corridor(s), Bellrock Offshore Wind Farm, Bowdun Offshore Wind Farm, Campion Offshore Wind Farm, Eastern Green Link 3 and Eastern Green Link 4. As these are Tier 3 projects, there are no scoping reports or EIA documents available 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. The activities associated with Bellrock Offshore Wind Farm, Bowdun Offshore Wind Farm, and Campion Offshore Wind Farm are likely to be similar to those of the Array. These activities include cable repair and reburial and use of jack-up vessels for infrastructure maintenance. The cumulative spatial extent of this impact in the operation and maintenance phase likely to be small in relation to the whole Array fish and shellfish ecology study area, although there is the potential for repeated disturbance to the habitats in the immediate vicinity infrastructure and cables. 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. 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 1044 and is not duplicated here.
  4. Colonisation of hard structures 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(s) 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 cumulative magnitude of impact of the Tier 3 projects is not expected to represent significant additional impact than that defined for the assessment of the Array alone. 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. However, this is expected to have beneficial effects, such as increased biodiversity and reef effects (Bender et al., 2020, De Mesel et al., 2015, Karlsson et al., 2022, Lindeboom et al., 2011, Mavraki et al., 2020). Although a shift from soft sediments to hard structures will constitute habitat loss for the offshore subtidal sands and gravels, which may provide suitable substrate for burying crabs and sandeel, for example, the localised nature of the footprints is likely to only result in a minor loss to the soft bottom substrates in the Array fish and shellfish ecology study area and wider North Sea as a whole. 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, volume 2, chapter 9 concluded 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.
  5. In addition to the Tier 1 projects, there were six Tier 3 projects identified in volume 2, chapter 9 with potential for cumulative effects associated with EMF during the operation and maintenance phase: Morven Offshore Export Cable Corridor(s), Bellrock Offshore Wind Farm, Bowdun Offshore Wind Farm, Campion Offshore Wind Farm, Eastern Green Link 3 and Eastern Green Link 4. As there is no published Scoping Report or EIA, there is no project-specific information regarding cable lengths, dimension, and voltages currently available for the Tier 3 projects. However, given the scale of the projects, it is likely that EMF related impacts associated with the Bellrock, Bowdun, and Campion Offshore Wind Farms will be of a similar in nature and extent to those of the Array and Morven BP-EnBW. Volume 2, chapter 9 concluded for most 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. For European lobster, Nephrops, edible crab and elasmobranchs, 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 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 significance, which is not significant in EIA terms.
  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
  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.

10.13. Proposed Monitoring

  1. This section outlines the proposed monitoring proposed for marine mammals. Proposed monitoring measures are outlined in Table 10.63   Open ▸ .
  2. As a part of the designed in measures ( Table 10.22   Open ▸ ), mooring lines and dynamic inter-array cables will undergo regular inspections during the operation and maintenance phase. The inspection frequency for mooring lines and dynamic inter-array cables is anticipated to be more frequent initially (e.g. years 1 and 2), and likely to decline in frequency after this, following a risk based approach. Any inspected or detected debris on the floating lines and cables will be recovered based on a risk assessment which considers impact on environment including risk to marine mammal, risk to asset integrity, and health & safety. In addition, Ossian OWFL will consider new technologies for monitoring of mooring lines/snagged gear and will agree approach to monitoring of mooring lines and associated removal of gear with NatureScot and MD-LOT prior to the operation and maintenance phase. This will reduce the risk of entanglement (largely secondary entanglement).
  3. The Applicant will engage with MD-LOT, NatureScot, and other relevant key stakeholders to identify and contribute to targeted and proportionate regional or strategic monitoring to better understand the environmental effects of offshore wind taking account of known evidence gaps. This may involve engaging and contributing to ongoing strategic initiatives from ScotMER forum (Scottish Government, 2024). (see Table 10.63   Open ▸ ).

 

Table 10.63:
Proposed Monitoring and the Method of Implementation for Marine Mammals

Table 10.63: Proposed Monitoring and the Method of Implementation for Marine Mammals

 

  1. No monitoring as a result of the CEA is proposed.