6.2. Fish and Shellfish Ecology

6.2.1. Introduction

This section of this Scoping Report presents the relevant fish and shellfish ecology data sources and baseline in the vicinity of the Array and the wider fish and shellfish ecology study area and considers the scope of assessment on fish and shellfish ecology from the construction, operation and maintenance, and decommissioning of the Array.

6.2.2. Study Area

As fish and shellfish are spatially and temporally variable, a broad study area has been defined for the purposes of the baseline characterisation and subsequent Array Environmental Impact Assessment (EIA) Report ( Figure 6.3 Open ▸ ). The fish and shellfish ecology study area encompasses the site boundary and a surrounding area defined by the boundary of the northern North Sea ( Figure 6.3 Open ▸ ). The fish and shellfish ecology study area provides a wider context for the spatially and temporally variable species and populations, including diadromous fish, which are known to occur within the Array. This area was considered appropriate as it will ensure the characterisation of all fish and shellfish receptors within the northern North Sea and is, therefore, large enough to consider all direct (e.g. habitat loss/disturbance within the site boundary) and indirect impacts (e.g. subsea noise over a wider area) associated with the Array on the identified receptors.

6.2.3. Baseline Environment

This section provides a brief summary of the baseline environment of the fish and shellfish ecology study area. A more detailed description is provided in Appendix 8.

Fish assemblage

The fish and shellfish ecology study area includes demersal, pelagic, diadromous, and elasmobranch fish species, including commercial and non-commercial species. Demersal species include cod Gadus morhua, haddock Melanogrammus aeglefinus, whiting Merlangius merlangus, plaice Pleuronectes platessa, lemon sole Microstomus kitt and sandeel Ammodytidae spp. Pelagic species include herring Clupea harengus, mackerel Scomber scrombus and sprat Sprattus sprattus. Elasmobranch species, such as spotted ray Raja montagui, thornback ray R. clavata, tope shark Galeorhinus galeus, small-spotted catshark Scyliorhinus canicula, spurdog Squalas acanthias, thorny skate Amblyraja radiata and cuckoo ray Leucoraja naevus, among others, have been observed in the fish and shellfish ecology study area (Coull, et al., 1998, Daan et al., 2005, Baxter et al., 2011, Ellis et al., 2012).
As set out in Appendix 8, a site-specific epibenthic beam trawl survey, comprising ten individual trawls, were conducted within the site boundary in July 2022. During these surveys, 16 fish species were observed, with the most abundant being the long rough dab Hippoglossoides platessoides, followed by plaice, common dab Limanda limanda, Norway pout Trisopterus esmarkii, lemon sole, sandeel Ammodytes marinus, and grey gurnard Eutrigla gurnardus.

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Figure 6.3: Site Boundary and Fish and Shellfish Ecology Study Area

Between 2011 and 2020, site-specific epifaunal beam trawl surveys were undertaken across the Berwick Bank and Seagreen 1 Offshore Wind Farms (formerly known as Seagreen Alpha and Bravo), located approximately 56 km and 50 km from the Array, respectively. They recorded a range of demersal species, such as common dab, long rough dab, lesser sandeel A. tobianus, Raitt’s sandeel A. marinus, four-bearded rockling Enchelyopus cimbrius, pogge Agonus cataphractus, butterfish Pholis gunnellus, Norwegian topknot Phrynorhombus norvegicus, reticulated dragonet Callionymus reticulatus, common dragonet Callionymus lyra, lemon sole, bullrout Myoxocephalus scorpius, and goby species (Gobiidae spp.). Commercial species such as plaice, whiting, cod, and red gurnard Chelidonichthys cuculus, were also recorded, as were smooth sandeel Gymnammodytes semisquamatus and greater sandeel Hyperoplus lanceolatus, and one elasmobranch species, the cuckoo ray (Seagreen, 2012, 2018, SSER, 2022).

Diadromous fish species

Diadromous fish (i.e. species that migrate between freshwater and the marine environment for breeding) could potentially migrate to and from rivers in the vicinity of the Array and, therefore, may migrate through the site boundary during certain periods of the year. Based on information on diadromous fish populations on the east coast of Scotland, the Berwick Bank and Seagreen 1 Offshore Wind Farm impact assessments identified eight diadromous fish species which have the potential to occur in offshore areas within the vicinity of the Array or coastal areas along the east of Scotland. These species were Atlantic salmon Salmo salar, sea trout S. trutta, sea lamprey Petromyzon marinus, river lamprey Lampetra fluviatilis, European eel Anguilla anguilla, allis shad Alosa alosa, twaite shad A. fallax, and sparling (European smelt) Osmerus eperlanus (Seagreen, 2018; SSER, 2022). It should be noted that river lamprey and sparling are primarily coastal species and are, therefore, unlikely to interact with the Array. The species that are therefore considered as having the greatest potential to be present within the vicinity of the Array are Atlantic salmon, sea trout, European eel, sea lamprey and allis and twaite shad.
No further site-specific surveys are proposed to inform the diadromous fish impact assessment. For the purposes of this Scoping Report, it will be assumed that the species mentioned in paragraph 353 are likely to be present within the fish and shellfish ecology study area during migration at key stages of their life cycles. This includes smolt migration from natal rivers and adult migration to spawning habitats. The aim of the impact assessment is to determine whether construction, operation and maintenance, or decommissioning activities have the potential to disrupt migration of these species. Therefore, migratory seasons will be an important element of the baseline characterisation and will be collated through desktop data sources (Malcolm et al., 2010, 2015, Godfrey et al., 2015, Hume, 2017, Lothian et al., 2017, Newton et al., 2017, Gardiner et al., 2018, Seagreen, 2018). More information on the timings of migration for diadromous fish species relevant to the Array is provided in Appendix 8.
The River Dee Special Area of Conservation (SAC), River South Esk SAC, and River Spey SAC are designated for Annex II Atlantic salmon and the symbiotic freshwater pearl mussel Margaritifera margaritifera as primary features. Although freshwater pearl mussels are not found in the offshore environment, they depend on the Atlantic salmon smelting population during their parasitic larval stage (Taeubert and Geist, 2017). Therefore, freshwater pearl mussel populations may be indirectly affected if Atlantic salmon are adversely affected by the Array.

Shellfish assemblage

The population structure of shellfish stocks around the UK is not well understood, with assessments largely based on previous fishing and landings data (Mesquita et al., 2016). Therefore, commercial landing data in the area provides an overview of species likely to be present. There are consistently high landings of Norway lobster Nephrops norvegicus, and medium to low landings of European lobster Hommarus gammarus, brown crab Cancer pagurus, velvet swimming crab Necora puber, king scallop Pecten maximus, whelks Buccinum undatum, razor clam Solen spp., surf clam Spisula spp., clams Mya arenaria, squid Loligo spp. and octopi Ommastrephidae (Mesquita et al., 2016, 2017, Marine Scotland, 2021a). Occasionally caught species include green crab Carcinus maenas, common prawn Palaemon serratus and queen scallop Aequipecten opercularis (Marine Scotland, 2021a).
During the site-specific benthic surveys conducted across the site boundary (Appendix 7), horse mussels Modiolus modiolus were observed scattered across the south-east and along the edge of the site boundary, however no M. modiolus beds were identified. Queen scallops were also recorded.

Spawning and/or nursery grounds

Potential nursery and spawning grounds were identified by Coull et al. (1998), for a range of species in the North Sea. These grounds were based on larvae, egg and benthic habitat survey data. In 2012, Ellis et al. reviewed this data for several species in the fish and shellfish ecology study area and provided updated data on the spatial distribution of low and high intensity nursery and spawning grounds.
Species with known spawning periods and nursery habitats identified within the fish and shellfish ecology study area are summarised in Table 6.6 Open ▸ and Apx. Table 7.3.

Table 6.6: Key Species with Geographic Spawning and Nursery Grounds which Overlap with the Site Boundary. Spawning and Nursery Intensity Specified Where Available. Adapted from Coull et al. (1998) and Ellis et al. (2012)

Common name	Species	Spawning	Nursery	Spawning Intensity	Nursery Intensity
Teleost fish
Anglerfish	Lophius piscatorius		✓		Low
Blue whiting	Micromesistius poutassou		✓		Low
Cod	Gadus morhua	✓	✓	Low	Low
European hake	Merluccius merluccius		✓		Low
Haddock	Melanogrammus aeglefinus		✓
Herring	Clupea harengus	Adjacent	✓		Low
Ling	Molva molva		✓		Low
Lemon sole	Microstomus kitt	✓	✓
Mackerel	Scomber scombrus		✓		Low
Plaice	Pleuronectes platessa	✓	✓	Low	High
Sandeel	Ammodytidae spp.	✓	✓	Low	High
Sprat	Sprattus sprattus	✓	✓
Whiting	Merlangius merlangus	✓	✓	Low	High
Elasmobranchs
Spotted ray	Raja montagui		✓		Low
Spurdog	Squalus acanthias		✓		Low

Designated sites

The site boundary does not overlap with any designated sites but there are several protected areas for fish and shellfish features within the fish and shellfish ecology study area. These sites are presented in Apx Table 8.4 Open ▸ . A full screening of the National Site Network and European sites with qualifying fish and shellfish features will be undertaken in the LSE Screening Report for the Array. Relevant fish and shellfish features will be fully considered and assessed in the fish and shellfish ecology chapter of the Array EIA Report, with the assessment on the European designated sites itself provided in the Report to Inform Appropriate Assessment (RIAA) accompanying the consent application.

6.2.4. Potential Array Impacts

A number of potential impacts which may occur during the construction, operation and maintenance, and decommissioning phases of the Array in the absence of designed in measures on fish and shellfish ecology have been identified in Table 6.7 Open ▸ .

Table 6.7: Potential Impacts Identified for Fish and Shellfish Ecology in the Absence of Designed In Measures

Potential Impact	Justification
Construction
Temporary habitat loss and disturbance	There is potential for temporary habitat loss and disturbance during construction operations (e.g. cable laying) and seabed preparation. If this temporary habitat loss or disturbance occurs over important sensitive habitats, such as spawning and/or nursery areas, impacts could be detrimental at local or population levels.
Subsea noise impacting fish and shellfish receptors	There is potential for disturbance, auditory injury and/or mortality for sensitive fish and shellfish species as a result of construction activities which increase subsea noise, specifically pile-driving. Subsea noise is also predicted to occur from vessels, however, with lower potential for impacts to fish and shellfish.
Effects to fish and shellfish ecology due to increased SSCs and associated sediment deposition	There is potential for an increase in SSCs and associated deposition during construction activities, such as seabed preparation and cable laying.
Effects to fish and shellfish ecology due to accidental release of pollutants	There is a risk of pollution being accidentally released from vessels and equipment involved during construction activities.
Operation and Maintenance
Long term habitat loss and disturbance	The presence of mooring and anchoring systems, Offshore Substation Platform (OSP) foundations, and scour and cable protection will result in loss of seabed habitats or change from one seabed habitat to another (e.g. soft sediments to hard substrates). If this habitat loss occurs over important sensitive habitats, such as spawning and/or nursery areas, impacts could be detrimental at a local or population levels.
Temporary habitat loss and disturbance	There is potential for temporary habitat loss and disturbance during maintenance operations, such as remedial cable burial operations. In addition, temporary habitat loss/disturbance may also occur due to movement of foundation mooring and anchoring systems or cables on the seabed during the operation and maintenance phase. If this temporary habitat loss or disturbance occurs over important sensitive habitats, such as spawning and/or nursery areas, impacts could be detrimental at local or population levels.
Effects to fish and shellfish ecology due to EMF from subsea electrical cabling	The subsea electrical cabling produces EMFs which may affect fish and shellfish trophic interactions and ecology (e.g. prey/predator relationships). These potential effects could occur due to changes in background EMFs inhibiting or interfering with fish and shellfish behaviours.
Effects to fish and shellfish ecology due to accidental release of pollutants	There is a risk of pollution being accidentally released from vessels and equipment involved during operation and maintenance activities.
Subsea noise from impacting fish and shellfish receptors	Subsea noise emissions will occur as a result of vessel movements and wind turbine operation, which could impact fish and shellfish receptors.
Colonisation of hard structures	Artificial structures placed on the seabed (e.g. foundations) are expected to be colonised by a range of marine species during the operation and maintenance phase. This could lead to localised increases in biodiversity and potential changes in prey/predator interactions.
Decommissioning
Temporary habitat loss and disturbance	There is potential for temporary habitat loss and disturbance due to decommissioning activities. If this temporary habitat loss or disturbance occurs over important sensitive habitats, such as spawning and/or nursery areas, impacts could be detrimental at local or population levels.
Subsea noise impacting fish and shellfish receptors	There is potential for disturbance, auditory injury and/or mortality for sensitive fish and shellfish receptors due to increases subsea noise associated with decommissioning activities. Subsea noise is also predicted to occur from vessels, however, with lower potential for impacts to fish and shellfish.
Colonisation of hard structures and their removal during decommissioning	Artificial structures placed on the seabed (e.g. foundations) are expected to be colonised by a range of marine species during the operation and maintenance phase. Removal of these structures during the decommissioning phase could result in loss of these artificial habitats, and potential changes to the communities present.
Effects to fish and shellfish ecology due to increased SSCs and associated sediment deposition	There is potential for an increase in SSCs and associated deposition during decommissioning activities, such as turbine foundation removal.
Effects to fish and shellfish ecology due to accidental release of pollutants	There is a risk of pollution being accidentally released from vessels and equipment involved during decommissioning activities.

6.2.5. Designed In Measures

The following designed in measures have been considered in the identification of potential impacts that have been scoped into the Array assessment, including how these can reduce potential for impact ( Table 6.9 Open ▸ ):

implementation of soft-start and ramp-up measures for piling;
development of, and adherence to, an appropriate Code of Construction Practice (CoCP);
development of, and adherence to, an EMP, including Marine Pollution Contingency Plan (MPCP); and
development of, and adherence to, a Decommissioning Programme.

The significance of the effects on fish and shellfish ecology may result in the requirement for additional mitigation. This will be consulted upon with the statutory consultees throughout the EIA and consultation processes. It is possible that particular mitigation may be required for species such as herring, which are particularly sensitive to subsea noise. This will be discussed via the EIA and consultation processes.

6.2.6. Relevant Consultations

A summary of the key points of agreement with relevant stakeholders and Statutory Nature Conservation Bodies (SNCBs) during the Array Scoping workshop is presented in Table 6.8 Open ▸ .

Table 6.8: Summary of Key Consultation on the Scoping Assessment for the Array

Date	Consultee(s)	Type of Consultation	Summary of Consultation	Where Addressed
15 November 2022	MS-LOT, MSS, NatureScot	Scoping workshop	Scoping out of effects on fish and shellfish ecology due to increases in SSCs and associated deposition was discussed and agreed upon, as was temporary habitat loss and disturbance within the operation phase. A currently unpublished report (Putland et al., In prep), was described to the stakeholders to support the proposal to scope out impacts to fish and shellfish due to operational noise. Data sources to inform scoping and assessment were presented to stakeholders, and additional literature sources were recommended by MSS.	Table 6.10 Open ▸

Date

Consultee(s)

Type of Consultation

Summary of Consultation

Where Addressed

15 November 2022

MS-LOT, MSS, NatureScot

Scoping workshop

Scoping out of effects on fish and shellfish ecology due to increases in SSCs and associated deposition was discussed and agreed upon, as was temporary habitat loss and disturbance within the operation phase. A currently unpublished report (Putland et al., In prep), was described to the stakeholders to support the proposal to scope out impacts to fish and shellfish due to operational noise.

Data sources to inform scoping and assessment were presented to stakeholders, and additional literature sources were recommended by MSS.

Table 6.10 Open ▸

6.2.7. Potential Impacts After the Implementation of Designed in Measures

Table 6.9 Open ▸ outlines the impacts which have been scoped into the Array assessment alongside a description of any additional and/or supporting analyses (e.g. modelling) that will be required to enable a full assessment of the impacts.
Table 6.10 Open ▸ describes the potential impacts to fish and shellfish ecology that have been scoped out of the assessment presently.

Table 6.9: Impacts Proposed to be Scoped In to the Array Assessment for Fish and Shellfish Ecology. Project Phase Refers to Construction (C), Operation and Maintenance (O) and Decommissioning (D) Phase of the Array

Impact	Project Phase			Justification (including consideration of designed in mitigation measures)	Data Collection and Analysis Required to Characterise the Baseline Environment for the EIA	Summary of Proposed Approach to Assessment
Impact	C	O	D			Summary of Proposed Approach to Assessment
Subsea noise impacting fish and shellfish receptors				Increased subsea noise generated during construction activities, specifically pile driving and decommissioning activities has the potential to result in mortality, injury and/or disturbance to sensitive fish and shellfish species. Designed in measures, such as piling soft-start and ramp-up measures, will be implemented to reduce the potential impact arising from this impact pathway.	A benthic subtidal ecology survey has been conducted to cover the site boundary area, following the methodology previously agreed with stakeholders (Appendix 7). Data from this survey will provide a characterisation of the seabed habitats which will allow for assessment of habitat suitability for various fish species (e.g. herring, sandeel and other species with specific habitat requirements), to ensure the baseline characterisation is site-specific and up to date. The epibenthic beam trawl survey, undertaken to characterise the benthic subtidal ecology baseline, was utilised to enhance the existing desktop data for fish and shellfish ecology within the fish and shellfish ecology study area. The survey was designed using best practice methods and was consulted and agreed upon with NatureScot and Marine Scotland. Additionally, as presented in Appendix 8, wide-ranging and comprehensive information and data sources will be used to characterise the baseline environment for fish and shellfish ecology.	The outputs of subsea noise modelling as detailed in section 5.2 will be used to inform this assessment. This will consider potential auditory injury across various species and the potential for disturbance to fish spawning and diadromous fish migration. In particular, the hearing ability of fish species, and both sound pressure and particle motion will be considered. Increases in subsea noise due to vessel usage are expected to be minimal and are therefore scoped out of the EIA ( Table 6.10 Open ▸ ).
Temporary habitat loss and disturbance				Construction activities (such as foundation mooring and anchoring system placements, cable installation and seabed preparation works), and decommissioning activities have the potential to impact fish and shellfish ecology through temporary, direct habitat loss and disturbance.		Impacts will be assessed quantitively where possible, however there is no specific modelling required to inform this impact. Quantitative assessment will largely focus on the footprint of the impacts on the seabed from activities during the construction, operation and maintenance, and decommissioning phases. This will be informed by information presented in the Project Description chapter of the EIA Report.
Long term habitat loss and disturbance				The presence of foundations (including mooring and anchoring systems and associated scour protection) and cable protection measures will result in loss of benthic habitat (e.g. change of seabed type from soft sediment to hard substrate). If this habitat loss occurs over important sensitive habitats, such as spawning and/or nursery areas, species-specific impacts could be detrimental at a local or population level. Adherence to an appropriate CoCP is considered a designed in measure for this impact, through management of construction activities and detailing EMPs and procedures to be adhered to during construction activities to manage the spatial footprint of activities which may result in long-term habitat loss.		Impacts will be assessed quantitively where possible, however, there is no specific modelling required to inform this impact. Quantitative assessment will largely focus on the footprint of the impacts on the seabed from activities during the operation and maintenance phase. This will be informed by information presented in the Project Description chapter of the EIA Report..
Effects to fish and shellfish ecology due to EMF from subsea electrical cabling				Changes in background EMFs generated through the subsea electrical cabling may interfere with fish and shellfish behaviours and affect fish and shellfish prey/predator relationships. A recent study has demonstrated that increased cable burial depth reduces the intensity of EMF for receptive species (Hutchison et al., 2021). Cable burial at an appropriate depth is therefore a designed in measure that may limit exposure to static inter-array cabling on the seabed.		No specific modelling is required to inform this impact assessment, however the potential for disturbance or disruption to diadromous fish migration will be considered using the best available evidence available on the effects of EMF on fish and shellfish ecology.
Colonisation of hard structures				Artificial structures, such as mooring and anchoring systems and foundations in the water column, and infrastructure placed on the seabed in the offshore environment, are expected to be colonised by a range of marine species. This has the potential to lead to localised increases in biodiversity and potential changes in ecological processes (e.g. prey/predator interactions).		No specific modelling is required to inform this impact assessment. As with the habitat loss impacts, this will be quantified where possible and draw on the best available scientific evidence on this subject.

Table 6.10: Impacts Proposed to be Scoped Out of the Array Assessment for Fish and Shellfish Ecology

Impact	Justification
Construction
Effects to fish and shellfish ecology due to accidental release of pollutants	Pollution could be accidentally released from vessels, equipment, and machinery associated within the construction phase. However, the potential risk of accidental release of pollutants is minimised by designed in mitigation measures, such as the development of, and adherence to, an appropriate CoCP, and an EMP which includes an MPCP. These designed in mitigation measures include planning for accidental spills, discuss all potential contaminants, and provide key emergency contact details. They will also adhere to good industry practice and relevant guidelines, such as the Convention for the Protection of the Marine Environment of the North-East Atlantic (OSPAR), International Marine Organisation (IMO), and MARPOL (International Convention for the Prevention of Pollution from Ships) guidelines for preventing pollution at sea. An accidental spill is, therefore, very unlikely, and even if it occurs, the magnitude will be minimised through measures outlined in the designed in measures for this impact (such the MPCP). Based on this information, and subject to consultation with regulators, advisory bodies and SNCBs, it is proposed to scope this impact out of further consideration within the EIA for fish and shellfish ecology.
Effects to fish and shellfish ecology due to increased SSCs and associated sediment deposition	Activities such as seabed preparation in the construction phase, and various decommissioning activities have the potential to result in increased SSCs and associated deposition. However, these potential increases in SSCs will be highly localised within a limited footprint, temporary, intermittent, of a short duration, and reversible, and the fish and shellfish receptors in the Array are not known to be sensitive to temporary increases in SSCs. Furthermore, adherence to an appropriate CoCP is a designed in mitigation measure for this impact. Therefore, increased SSCs and associated deposition are not considered to have potential significant effects on fish and shellfish ecology, and it is proposed to scope this impact out of further consideration within the EIA.
Operation and Maintenance
Effects to fish and shellfish ecology due to accidental release of pollutants	As above for the construction phase.
Subsea noise from wind turbine operation impacting fish and shellfish receptors	There are no designed in measures necessary as the subsea noise generated by operational wind turbines occurs at a very low frequency and low sound pressure level (Andersson et al., 2011). Studies have demonstrated that subsea noise from operational wind turbines could only cause a possible behavioural reaction within metres from the wind turbine (Sigray and Andersson, 2011), which is highly unlikely to occur with respect to fish and shellfish species. These observations from earlier offshore wind farms (with smaller turbines) are supported by modelling of the noise emissions from larger offshore wind turbines, which demonstrate that the risk of injury of behavioural effects on fish and shellfish populations is negligible (SSER, 2022). Putland et al. (in prep) recently presented a study into operational noise of floating offshore wind turbines; their findings indicate that operational noise is comparable to that of fixed bottom turbines, generating low-level noise which is unlikely to cause significance disturbance effects to fish. Therefore, levels of noise generated by operational wind turbines are not considered to have potential significant effects on fish and shellfish receptors, and it is proposed to scope this impact out of further consideration within the EIA for fish and shellfish ecology.
Subsea noise from vessels impacting fish and shellfish receptors	There are no designed in measures necessary as subsea noise generated by operational vessels is likely to be low and potential impacts to fish and shellfish receptors are only likely to occur if individuals remained within their immediate vicinity (i.e. within metres) for several hours/days. This is highly unlikely to occur. Therefore, levels of noise generated by vessels are not considered to have potential effects on fish and shellfish receptors, and it is proposed to scope this impact out of further consideration within the EIA for fish and shellfish ecology. The proposal to scope this impact out of the assessment for fish and shellfish ecology is in line with that of similar projects (e.g. Inch Cape; Red Rock Power Limited, 2018, Seagreen 1; Seagreen, 2012, Berwick Bank; SSER, 2022).
Temporary habitat loss and disturbance	There is potential for temporary habitat loss and disturbance to occur during the operation and maintenance phase through activities such as cable repair. However, these are likely to be intermittent and of a short-term duration in comparison to activities within the construction and decommissioning phases. Therefore, this impact is not considered to have significant effects on fish and shellfish ecology, and it is proposed to scope it out of further consideration within the EIA for fish and shellfish ecology.
Decommissioning
Effects to fish and shellfish ecology due to accidental release of pollutants	As above for the construction phase.
Effects to fish and shellfish ecology due to increased SSCs and associated sediment deposition	As above for the construction phase.
Subsea noise from vessels impacting fish and shellfish receptors	As above for the operation and maintenance phase.

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