Tier 1

                        All phases

Magnitude of impact

374.           There were two Tier 1 projects identified with potential for cumulative LSE1 associated with this impact:

  • all phases of the Proposed offshore export cable corridor(s); and
  • the operation and maintenance and decommissioning phases of the Eastern Green Link 2 ( Table 9.31   Open ▸ ).

375.           There is currently no EIA Report available for the Proposed offshore export cable corridor(s). However, given that the Proposed offshore export cable corridor(s) is a HDVC subsea power cable, it is expected that the amount of infrastructure installed which may constitute long term habitat loss will be lower than that for the Array. It is likely that long term habitat loss will occur at the Tier 1 projects because of cable protection and crossing protection.

376.           For the Array, up to 19.27 km2 of long term habitat loss and disturbance may occur due to the installation of infrastructure, and an additional 778,464 m2 due to long term seabed disturbance from mooring lines and dynamic cabling ( Table 9.13   Open ▸ ). Within the Environmental Appraisal Report for the Eastern Green Link 2, a total footprint of up to 2.20 km2 long term habitat loss and disturbance was predicted to occur ( Table 9.32   Open ▸ ) (National Grid Electricity Transmission and Scottish Hydro Electric Transmission plc, 2022). It should be noted that footprint of long term habitat loss associated with the Eastern Green Link 2 will be spread out over a large portion of the North Sea (see Figure 9.10   Open ▸ , therefore will be substantially far from that of the Array at points (i.e. much of the habitat loss would occur outside the fish and shellfish ecology study area). This was comprised of up to 2 km2 of rock berm and up to 0.2 km2 of pipeline and cable crossing protection (National Grid Electricity Transmission and Scottish Hydro Electric Transmission plc, 2022).

 

Table 9.32:
Cumulative Footprint of Long Term Habitat Loss and Disturbance (km2) for the Tier 1 Projects

Table 9.32: Cumulative Footprint of Long Term Habitat Loss and Disturbance (km2) for the Tier 1 Projects

 

377.           This impact presents some measurable but minor long term loss of and alteration to the affected areas of seabed within the entire fish and shellfish ecology study area and wider North Sea as a whole. The cumulative magnitude of impact of the Array with the Tier 1 projects represents no additional material  impact than that defined for the assessment of the Array alone (paragraphs 108 et seq.). Following decommissioning, many of the hard structures (e.g. scour and cable protection) may be left in situ. Therefore, the long term habitat loss effect may persist beyond decommissioning. However, at this stage, it is not possible to quantify the extent of this habitat loss using the MDS methodology.

378.           The cumulative impact is predicted to be of local spatial extent, long term duration, continuous and of low reversibility within the construction and operation and maintenance phase. It is predicted that the impact will affect the receptor directly. The magnitude is therefore considered to be low.

Sensitivity of receptor

379.           The sensitivities of the fish and shellfish IEFs are as previously described above for the assessment of the Array alone (paragraphs 112 et seq.).

Significance of effect

380.           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.

381.           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.

382.           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.

Further mitigation and residual effect

383.           No secondary mitigation is considered necessary because the likely cumulative effect in the absence of further mitigation (beyond the designed in measures outlined in section 9.10) is not significant in EIA terms.

                        Tier 2

                        All phases

384.           In addition to the Tier 1 projects, there was one Tier 2 project identified with potential for cumulative LSE1 associated with this impact: the operation and maintenance and decommissioning phases of Morven Offshore Wind Farm ( Table 9.30   Open ▸ ). According to the Morven Offshore Wind Farm 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 Offshore Wind Farm (Morven Offshore Wind Limited, 2023).

385.           For the Array, up to 19.27 km2 of long term habitat loss and disturbance may occur due to the installation of infrastructure, and an additional 778,464 m2 due to long term seabed disturbance from mooring lines and dynamic cabling ( Table 9.13   Open ▸ ). Long term habitat loss and disturbance impacts associated with the Morven Offshore Wind Farm are expected to be similar in nature and extent to the Array, with the exception of the fixed foundations at Morven Offshore Wind Farm, of which the extent of habitat loss is not possible to quantify at this stage using the MDS methodology. As outlined in paragraphs 87 et seq. for the Array alone, the impacts of site preparation and construction and operation and maintenance activities are expected to be temporary and reversible, the cumulative magnitude of impact is still not expected to represent additional material impact than that defined for the assessment of the Array alone (paragraphs 108 et seq.) because it represents only a small proportion of the habitats within the fish and shellfish ecology study area and the wider North Sea area.

386.           Following decommissioning, many of the hard structures (e.g. scour and cable protection) may be left in situ. Therefore, the long term habitat loss effect may persist beyond decommissioning. At this stage, it is not possible to quantify the extent of this habitat loss due to a lack of an accurate MDS for these projects, however when considering experience from other similar projects it is considered likely that impacts from scour and cable protection would be localised to small discrete areas representing a very small proportion of seabed within project boundaries.

387.           The cumulative impact is predicted to be of local spatial extent, long term duration, continuous and of low reversibility within the construction and operation and maintenance phase. It is predicted that the impact will affect the receptor directly. The magnitude is therefore, considered to be low.

Sensitivity of receptor

388.           The sensitivities of the fish and shellfish IEFs are as previously described above for the assessment of the Array alone (paragraphs 112 et seq.).

Significance of effect

389.           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.

390.           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.

391.           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.

Further mitigation and residual effect

392.           No secondary mitigation is considered necessary because the likely cumulative effect in the absence of further mitigation (beyond the designed in measures outlined in section 9.10) is not significant in EIA terms.

                        Tier 3

                        All phases

Magnitude of impact

393.           In addition to the Tier 1 and Tier 2 projects, there were six Tier 3 projects identified with potential for cumulative effects associated with this impact:

  • Morven Offshore Export Cable Corridor(s);
  • Bellrock Offshore Wind Farm;
  • Bowdun Offshore Wind Farm; and
  • Campion Offshore Wind Farm;
  • Eastern Green Link 3; and
  • Eastern Green Link 4 ( Table 9.30   Open ▸ ).

394.           As these are Tier 3 projects, there are no Scoping Reports or EIA documents publicly available. Therefore, there is no information available on the impact that these Tier 3 projects will have on fish and shellfish ecology.

395.           For the Array, up to 19.27 km2 of long term habitat loss and disturbance may occur due to the installation of infrastructure, and an additional 778,464 m2 due to long term seabed disturbance from mooring lines and dynamic cabling ( Table 9.13   Open ▸ ). The three Tier 3 offshore wind farms are either fully floating or containing some floating wind turbines, similar to the Array, which is a fully floating project. 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 using the MDS methodology at this stage. As outlined in paragraphs 87 et seq. for the Array alone, the impacts of site preparation and construction and operation and maintenance activities are expected to be temporary and reversible.

396.           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 (see paragraphs 374 et seq.).

397.           Following decommissioning, many of the hard structures (e.g. scour and cable protection) may be left in situ. Therefore, the long term habitat loss impact may persist beyond decommissioning. At this stage, it is not possible to quantify the extent of this habitat loss using the MDS methodology, however when considering experience from other similar projects it is considered likely that impacts from scour and cable protection would be localised to small discrete areas representing a very small proportion of seabed within project boundaries

398.           The cumulative spatial extent of this impact in the construction and operation and maintenance phase likely to be small in relation to the whole fish and shellfish ecology study area. The cumulative magnitude of impact of the Tier 3 assessment is not expected to represent additional material impact than that defined for the assessment of the Array alone (paragraphs 108 et seq.).

399.           The cumulative impact is predicted to be of local spatial extent, long 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

400.           The sensitivities of the fish and shellfish IEFs are as previously described above for the assessment of the Array alone (paragraphs 112 et seq.).

Significance of effect

401.           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.

402.           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.

403.           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.

Further mitigation and residual effect

404.           No secondary mitigation is considered necessary because the likely cumulative effect in the absence of further mitigation (beyond the designed in measures outlined in section 9.10) is not significant in EIA terms.

Colonisation of Hard Structures

405.           The introduction of the hard structures at the Array and the other projects may potentially affect fish and shellfish ecology receptors by providing new habitat and ecosystem function in areas typically otherwise characterised by soft, sedimentary environments, essentially replicating naturally occurring rocky habitats (Karlsson et al., 2022). Hard structures include foundations, scour protection, cable protection, cable crossing protection, and subsea junction boxes. These artificial hard structures are expected to be colonised by a range of organisms, which could lead to local biodiversity increases which may be beneficial to some fish and shellfish (particularly demersal generalists) or be detrimental to others (such as sandeel and crabs, during certain life history stages when they bury into the seabed). For the purposes of this Array EIA Report, this impact has been assessed using the tiered approach outlined in section9.12.1. The plans and projects screened into the CEA for this impact and their respective tiers are outlined in Table 9.31   Open ▸ .

                        Tier 1

                        All phases

Magnitude of impact

406.           There were two Tier 1 projects identified with potential for cumulative LSE1 associated with this impact:

  • Proposed offshore export cable corridor(s); and
  • Eastern Green Link 2 ( Table 9.31   Open ▸ ).

407.           There is currently no Offshore EIA Report available for the Proposed offshore export cable corridor(s). However, given that the Proposed offshore export cable corridor(s) and Proposed onshore transmission infrastructure is a HDVC subsea power cable, it is expected that the amount of infrastructure installed which may lead to colonisation of hard structures will be lower than that for the Array. The preferred means of cable protection for the Proposed offshore export cable corridor(s) would be burial, with rock protection required at crossing points or where target burial depth cannot be achieved. It is likely that colonisation of hard structures will occur at the Tier 1 projects because of cable protection and crossing protection.

408.           Within the Environmental Appraisal Report for the Eastern Green Link 2, a total footprint of up to 2.20 km2 of artificial hard substrates was predicted to be installed ( Table 9.33   Open ▸ ), comprised of up to 2 km2 of rock berm and up to 0.2 km2 of pipeline and cable crossing protection (National Grid Electricity Transmission and Scottish Hydro Electric Transmission plc, 2022). For the Proposed offshore export cable corridor(s), the area of installed hard substrate is expected to be similar to that of the Eastern Green Link 2, given the similarity in nature of the two Tier 1 projects, although it is not possible to accurately quantify the extent of the footprint at this time. The cumulative spatial extent of this impact in the operation and maintenance phase therefore likely to be small in relation to the whole fish and shellfish ecology study area.

 

Table 9.33:
Cumulative Footprint of Hard Structures Installed (km2) for the Tier 1 Projects

Table 9.33: Cumulative Footprint of Hard Structures Installed (km2) for the Tier 1 Projects

 

409.           It is expected that these artificial hard structures will be colonised by epifaunal species local to the fish and shellfish ecology study area. However, 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, such as increased biodiversity, greater shelter/protection opportunities, greater prey availabilities and potential reef effects (Bender et al., 2020; Langhamer and Wihelmsson, 2009).

410.           Although this impact is expected to be beneficial in terms of increasing biodiversity and enhancing reef effects, the installation of hard structures will result in habitat loss for subtidal sands and gravels, which may be suitable burial substrate for species like edible crab and sandeel. However, given the wide availability of such habitats over the fish and shellfish ecology study area and wider North Sea, and the localised nature of this impact, this impact is only expected to result in minor loss or alteration to the soft bottom sediments. The cumulative magnitude of impact of the Array with the Tier 1 projects is not expected to represent additional material impact than that defined for the assessment of the Array alone (paragraph 138).

411.           Following decommissioning, many of the hard structures (e.g. scour and cable protection) may be left in situ. Therefore, colonisation on these hard structures may persist beyond decommissioning. However, at this stage, it is not possible to quantify the extent of this colonisation effect using the MDS methodology.

412.           Overall, for all IEFs, the cumulative impact is predicted to be of local spatial extent, long term duration, continuous, 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

413.           The sensitivities of the fish and shellfish IEFs are as previously described above for the assessment of the Array alone (paragraphs 139 et seq.).

Significance of effect

414.           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.

415.           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.

Further mitigation and residual effect

416.           No secondary mitigation is considered necessary because the likely cumulative effect in the absence of further mitigation (beyond the designed in measures outlined in section 9.10) is not significant in EIA terms.

                        Tier 2

                        All phases

Magnitude of impact

417.           In addition to the Tier 1 projects, there was one Tier 2 project identified with potential for cumulative effects associated with this impact: the operation and maintenance phase of Morven Offshore Wind Farm ( Table 9.30   Open ▸ ). According to the Morven Offshore Wind Farm Scoping Report, hard structures installed at the Morven Offshore Wind Farm are expected to include foundations, scour protection, and cable protection (Morven Offshore Wind Limited, 2023).

418.           For the Array, up to 19.27 km2 of hard structures may be installed ( Table 9.13   Open ▸ ). Colonisation of hard structures associated with the Morven Offshore Wind Farm are expected to be similar in nature and extent to the Array, with the exception of the fixed foundations at Morven Offshore Wind Farm, of which the extent of habitat loss is not possible to quantify at this stage using the MDS methodology). As outlined in paragraphs 155 to 157 for the Array alone, the impacts of site preparation and construction and operation and maintenance activities are expected to be of local spatial extent, long term duration, continuous, and low reversibility. It is predicted that the impact will affect the receptor directly. The magnitude is therefore, considered to be low.

419.           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 ecology receptors (Bender et al., 2020; Langhamer and Wihelmsson, 2009).

420.           Following decommissioning, many of the hard structures (e.g. scour and cable protection) may be left in situ. Therefore, colonisation on these hard structures may persist beyond decommissioning. However, at this stage, it is not possible to quantify the extent of this colonisation effect using the MDS methodology.

421.           Overall, for all IEFs, the cumulative impact is predicted to be of local spatial extent, long term duration, continuous, 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

422.           The sensitivities of the fish and shellfish IEFs are as previously described above for the assessment of the Array alone (paragraphs 139 et seq.).

Significance of effect

423.           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.

424.           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.

Further mitigation and residual effect

425.           No secondary mitigation is considered necessary because the likely cumulative effect in the absence of further mitigation (beyond the designed in measures outlined in section 9.10) is not significant in EIA terms.

                        Tier 3

                        All phases

Magnitude of impact

426.           In addition to the Tier 1 and Tier 2 projects, there were six Tier 3 projects identified with potential for cumulative effects associated with this impact:

  • 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 ( Table 9.30   Open ▸ ).

427.           As these are Tier 3 projects, there are no Scoping Reports or EIA documents publicly available. Therefore, there is no information available on the impact that these Tier 3 projects will have on fish and shellfish ecology. For the Array, up to 19.27 km2 of hard structures may be installed ( Table 9.13   Open ▸ ). Colonisation of hard structures associated 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. The cumulative magnitude of impact of the Tier 3 projects is not expected to represent additional material impact than that defined for the assessment of the Array alone (paragraph 138).

428.           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 ecology receptors. However, this is expected to have beneficial effects, such as increased biodiversity and reef effects (Bender et al., 2020; Langhamer and Wihelmsson, 2009). 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 fish and shellfish ecology study area and wider North Sea as a whole.

429.           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 (see paragraphs 406 et seq.).

430.           Following decommissioning, many of the hard structures (e.g. scour and cable protection) may be left in situ. Therefore, colonisation on these hard structures may persist beyond decommissioning. However, at this stage, it is not possible to quantify the extent of this colonisation effect using the MDS methodology.

431.           Overall, for all IEFs, the cumulative impact is predicted to be of local spatial extent, long term duration, continuous, 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

432.           The sensitivities of the fish and shellfish IEFs are as previously described above for the assessment of the Array alone (paragraphs 139 et seq.).

Significance of effect

433.           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.

434.           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, bye of negligible to minor adverse significance, which is not significant in EIA terms.

Further mitigation and residual effect

435.           No secondary mitigation is considered necessary because the likely cumulative effect in the absence of further mitigation (beyond the designed in measures outlined in section 9.10) is not significant in EIA terms.

Underwater noise from piling and UXO clearance impacting fish and shellfish receptors

436.           Underwater noise may arise from the Array’s construction due to piling for the installation of wind turbines and OSPs, and due to UXO clearance. There is the potential for cumulative impacts from underwater noise generation as a result of the construction phase of the Array and other offshore developments, which may impact fish and shellfish ecology receptors. For the purposes of this Array EIA Report, this impact has been assessed using the tiered approach outlined in section 9.12.1. The plans and projects screened into the CEA for this impact and their respective tiers are outlined in Table 9.31   Open ▸ .

                        Tier 1

                        Site preparation and construction phase

Magnitude of impact

437.           There were two Tier 1 projects identified with potential for cumulative effects associated with this impact:

  • Proposed offshore export cable corridor(s); and
  • Berwick Bank Offshore Wind Farm ( Table 9.30   Open ▸ ).

438.           The MDS for the Array’s construction is given in Table 9.13   Open ▸ , which considers the greatest impact from underwater noise on fish and shellfish IEFs, based on the greatest hammer energy. This scenario is represented by the installation of up to 265 semi-submersible floating foundations, with up to six anchors per foundation and one 4.5 m diameter pile per anchor (1,590 piles) for wind turbines, and up to three large and 12 small jacket foundations (total 216 piles) for OSPs, with all piles installed via impact piling. Herring spawning grounds exist to the north of the Array, and low intensity spawning grounds for cod exist throughout the Array, which span out to the North Sea’s offshore waters. This is also the case for sandeel and plaice spawning grounds.

439.           Currently, there is no EIA Report available for the Proposed offshore export cable corridor(s), though construction is likely to be of medium term duration, with noise being intermittent. Although there is no information on construction activities associated with the Proposed offshore export cable corridor(s), it is not expected that piling will be included in the project description (as this is a cable project). As such, noise impacts which have the potential to affect fish and shellfish ecology receptors are limited to UXO clearance operations during site preparation. While there is no site-specific information on these impacts, it is expected they would be similar to those assessed for the project alone (paragraphs 155 to 157).

440.           Berwick Bank Offshore Wind Farm’s pre-construction phase will involve clearance of up to 15 UXOs (a maximum of 300 kg) within the inter-array area or offshore export cable route, and single donor charge of up to 80 g NEQ for each clearance event. Up to 500 g NEQ may be used for a clearance shot to neutralise residual explosive material, with up to two detonations within 24 hours and clearance occurring during daylight only (SSER, 2022a).

441.           During the construction phase for the Berwick Bank Offshore Wind Farm, up to 179 piles jacket foundations with up to four legs per foundation (1,432 piles) have been assessed for wind turbines. The maximum hammer energy is up to 4,000 kJ with a realistic maximum hammer energy of 3,000 kJ. Two concurrent piling events will occur with a minimum of 900 m and maximum of 49.3 km distance between these two events. Up to ten hours of absolute maximum piling per pile may occur with a wind turbine piling duration of 14,320 hours and a realistic maximum of 12,888 hours.

442.           During the construction phase for the Berwick Bank Offshore Wind Farm, up to eight jacket foundations with up to six legs per foundation (64 piles) have been assessed for OSPs/offshore converter substation platforms, with a maximum hammer energy of 4,000 kJ. Piling may occur for up to eight hours, with a total piling duration of 1,792 hours (realistic maximum) or 2,048 hours (absolute maximum). The total piling phase is over 52 months within a construction period of 96 months.

443.           The Berwick Bank Offshore Wind Farm underwater noise assessment considered effects (including mortality, injury and behavioural effects) on a similar range of fish and shellfish receptors as the Array. In particular, the risks to sandeel and herring were considered in detail. In line with the assessment for the Array alone, the Berwick Bank Offshore Wind Farm assessment predicted that injury effects would be limited in extent and although behavioural effects would occur across a wider area, the effects would be temporary, reversible and would not result in significant effects on fish and shellfish receptors, including spawning or nursery habitats.

444.           The construction of the Array, and of Berwick Bank Offshore Wind Farm, will coincide for only two years (2031 and 2032). Furthermore, due to the large distance between the projects (56.84 km), there is limited potential for noise contours to interact.

445.           The cumulative impact of underwater noise on fish and shellfish ecology receptors during the construction phase is predicted to be of regional spatial extent, medium term duration, intermittent and high reversibility. It is predicted that the impact may affect the receptor directly. The magnitude is therefore considered to be low.

Sensitivity of receptor

446.           The sensitivities of the fish and shellfish IEFs are as previously described above for the assessment of the Array alone (paragraphs 168 et seq.).

Significance of effect

447.           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 significance, which is not significant in EIA terms.

448.           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. This is due to the hearing sensitivity of herring, coupled with the presence of a small proportion of undetermined intensity spawning grounds within range of underwater sound levels which may give rise to limited behavioural effects, noting impacts are not expected to extend to the core herring spawning habitat.

Further mitigation and residual effect

449.           No secondary mitigation is considered necessary because the likely cumulative effect in the absence of further mitigation (beyond the designed in measures outlined in section 9.10) is not significant in EIA terms.