Appendix 8 Fish and Shellfish Ecology – Baseline EnvironmentFish and Shellfish Ecology – Baseline Environment
8.1. Desktop Study
- An initial desk-based review of literature and data sources to support this Scoping Report has identified a number of data sources which provide coverage of the fish and shellfish ecology study area, including the Array and the wider northern North Sea. A summary of these data sources is provided in Apx Table 8.1 Open ▸ below. These sources have been summarised briefly in the following sections and are supplemented with the results of site-specific surveys to inform the baseline characterisation for fish and shellfish ecology within this Scoping Report. These data sources, and others, will be expanded on further within the fish and shellfish chapter of the Array Environmental Impact Assessment (EIA) Report to ensure a robust characterisation is provided. The fish and shellfish ecology baseline assessment will also be informed through the commercial fisheries baseline characterisation (Appendix 10) and through consultation with relevant commercial fisheries bodies.
Apx Table 8.1: Summary of Key Desktop Reports for Fish and Shellfish Ecology
8.2. Site-specific Survey Data
- Site-specific grab sampling and seabed imagery sampling (supported by geophysical datasets) across the site boundary will be used to characterise the seabed types and sediment composition. The site-specific surveys also included epibenthic beam trawls, which will be used to support the baseline characterisation, particularly with respect to records of small demersal fish species present within the site boundary. While these surveys were primarily designed to inform the benthic subtidal ecology baseline characterisation (see Appendix 6), they will provide useful information on general seabed types, sediment suitability for fish spawning (specifically sandeel Ammodytidae spp. and herring Clupea harengus) and/or habitat for benthic fish and shellfish species. These may also provide opportunistic fish and shellfish records which can be used to inform the baseline characterisation. Site-specific data will therefore be used to enhance the fish and shellfish ecology data collated during the desk-based review of existing literature.
8.3. Baseline Characterisation
8.3.1 Fish Assemblage
- A range of biotic and abiotic factors are involved in the determination of fish distribution. Abiotic factors include water temperature, salinity, depth, local scale habitat features and substrate type, and biotic factors include predator-prey interactions, inter- and intra-specific competition and anthropogenic parameters such as marine and coastal infrastructure and commercial fishing intensity.
- The Array is situated in ICES area 4b, and within the south-east of the Scottish North Sea. The fish assemblage in the fish and shellfish ecology study area, which extends throughout the northern North Sea, includes demersal, pelagic, diadromous and elasmobranch species, many of commercial importance. Demersal species in the area include cod Gadus morhua, haddock Melanogrammus aeglefinus, whiting Merlangius merlangus, plaice Pleuronectes platessa, lemon sole Microstomus kitt, and sandeels. Sandeels, which are a crucial forage fish for many other species, are one of the most abundant species in the North Sea, accounting for approximately 25% of fish biomass (Christensen et al., 2013). Pelagic species include herring, mackerel Scomber scombrus and sprat Sprattus sprattus. Elasmobranchs (sharks, skates and rays) are also likely to be present in the vicinity of the Array and the wider fish and shellfish ecology study area. 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).
- In July 2022, epibenthic beam trawl surveys were conducted at ten locations within the site boundary (see Appendix 6, Apx Figure 6.1 Open ▸ ). There were 16 fish species 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. Both adult and juvenile long rough dab, Norway pout, and grey gurnard were recorded. Other species recorded in lower abundance were pogge Agonus cataphractus, gobies Aphia minuta and Pomatoschistus minutus, scaldfish Arnoglossus laterna, Lotidae and Argentinidae species.
- In August 2020, epibenthic beam trawl surveys were conducted across 15 locations within the proposed Berwick Bank Offshore Wind Farm, located 56.77 km to the south-west of the Array as part of the benthic subtidal surveys undertaken for the Berwick Bank Offshore Wind Farm EIA. A total of 553 bony fish across 21 taxa were recorded during the surveys, with common dab being the most abundant species (n = 167), followed by long rough dab, lesser sandeel Ammodytes tobianus and gobies Pomatoschistus sp. Common dab, long rough dab and lesser sandeel were recorded in trawls across the Berwick Bank Offshore Wind Farm, while gobies were only recorded in trawls within Berwick Bank’s Export Cable Corridors (ECCs). Two anglerfish and four-bearded rockling Enchelyopus cimbrius were also observed during the trawls (SSER, 2022).
- A total of a total of 53 epibenthic trawls were conducted in 2011 to inform the fish and shellfish ecology baseline characterisation for the nearby Seagreen 1 (formerly Seagreen Alpha and Bravo) Offshore Wind Farm (located 50.72 km to the west of the Array). Species observed in at least 50% of trawls were: pogge, common dab, gobies P. lozanoi and P. norvegicus, sandeels A. marinus, butterfish Pholis gunnellus, Norwegian topknot Phrynorhombus norvegicus, reticulated dragonet Callionymus reticulatus, common dragonet C. lyra, lemon sole and bull rout Myoxocephalus scorpius. 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).
8.3.2 Diadromous fish species
- Diadromous species refer to species that migrate between fresh water and the marine environment. Many species spawn in freshwater habitats and migrate to the marine environment for their adult phase, while European eel Anguilla anguilla spawn in the marine environment and return to freshwater as juveniles, i.e. glass eels and elvers. Diadromous fish are known to migrate to and from rivers on the east coast of Scotland and, therefore, may migrate through the fish and shellfish ecology study area at certain periods of the year. The fish and shellfish ecology assessments for the nearby Seagreen 1 (formerly Seagreen Alpha and Bravo) and Berwick Bank Offshore Wind Farms recognised eight diadromous fish species of relevance within the fish and shellfish ecology study area. These species were Atlantic salmon Salmo salar, sea trout S. trutta, sea lamprey Petromyzon marinus, river lamprey Lampetra fluviatilis, European eel, Allis shad Alosa alosa, twaite shad A. fallax, and sparling (European smelt) Osmerus eperlanus (Seagreen, 2018; SSER, 2022). Atlantic salmon, sea trout, European eel, sea lamprey and the two shad species are considered as having the potential to occur within the Array, with river lamprey and sparling known to have more coastal and estuarine distributions (ABPMer, 2019, NatureScot, 2022a, 2022b, SSER, 2022) and are, therefore, less likely to occur in offshore areas such as the Array.
- The River Dee Special Area of Conservation (SAC), River South Esk SAC, and River Spey SAC are primarily designated for Annex II Atlantic salmon and the symbiotic freshwater pearl mussel Margaritifera margaritifera. Although freshwater pearl mussels are not found in the offshore marine 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.
- No site-specific surveys are proposed to inform the impact assessment on diadromous fish species. For the purposes of this Scoping Report, it is assumed that the aforementioned species have the potential to be present within the Array during migration at key stages of their life cycles. This includes smolt migration from natal rivers and adult migration to spawning habitats. The main aim of the impact assessment for diadromous species will be determining whether construction, operation and maintenance, or decommissioning activities have the potential to disrupt migration. Migratory seasons will therefore be important and will be informed through desktop data sources (Maitland and Hatton-Ellis, 2003; 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). Apx Table 8.2 Open ▸ provides an overview of the timings of migration for diadromous fish species relevant to the Array.
Apx Table 8.2: Timings and Durations of Diadromous Fish Species Relevant to the Array
8.3.3 Spawning and/or Nursery Grounds
- Spawning and nursery grounds are described as sensitive areas as they are essential habitats for species during important, yet sensitive, stages of their life cycles (Aires, et al., 2014). 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. Ellis et al. (2010, 2012) reviewed this data for several species in the fish and shellfish ecology study area and provided an updated data on the spatial distribution of low and high intensity nursery and spawning grounds.
- Based on these key datasets, spawning and nursery areas for numerous species that overlap with or are located in close proximity to the Array have been identified. This includes high intensity nursery areas for cod, herring and whiting, and high intensity spawning areas for sandeels. This data has been summarised in Apx Table 8.3 Open ▸ and illustrated in Apx Figure 8.1 Open ▸ to Apx Figure 8.4 Open ▸ .
- As illustrated, there are widespread nursery and spawning grounds in the vicinity of the Array, many of which extend over much of the North Sea. Species such as sandeels and herring utilise specific demersal habitats to deposit their eggs and are therefore vulnerable to anthropogenic activities which impact the seabed. Furthermore, herring are classed under the guidelines for undertaking assessments of the effects of subsea noise on fish populations, as published by Popper et al. (2014), as a “Group Three” species according to their hearing sensitivity. Group Three species are those which have a swim bladder or other gas volume, are susceptible to barotrauma, and can detect sound pressure as well as particle motion (Wahlberg and Westerberg, 2005; Popper et al., 2014; Seagreen, 2018). Sandeels (and other species, such as mackerel and flatfish), are classified as a “Group One” species, as they have no swim bladder. Group One species are less susceptible to barotrauma and only detect particle motion, not sound pressure. A further review of the spawning and nursery grounds will be undertaken to support the fish and shellfish ecology assessment in order to ensure an accurate and up to date characterisation of spawning habitats and activity for herring in the Zone of Influence (ZoI) of the Array. Species-specific guidance will be followed where possible, such as the guidelines set out by Boyle and New (2018) which analyse multiple years of IHLS data to present heatmaps of herring spawning hotspots to inform impact assessments of elevated subsea noise during piling. In addition, the Particle Size Analysis (PSA) of grab samples collected during the site-specific surveys will be used to assess herring spawning habitat suitability using classifications derived from Reach et al. (2013).
- Similarly, due to their vulnerability to anthropogenic activities and their historic population declines within the North Sea, spawning habitat suitability for sandeels will also be undertaken. This will follow a similar approach to that for herring, through PSA of grab samples from the site-specific survey, but using habitat suitability classifications derived from Latto et al. (2013). Furthermore, the predicted distribution model for sandeels in the North Sea published by Langton et al., (2021) will be mapped in relation to the site boundary, in order to determine areas where the probability of sandeel presence and density are high.
Apx Figure 8.1: Spawning and Nursery Areas Overlapping with the Site Boundary for Anglerfish, Blue Whiting, Cod and European Hake (Source: Coull et al., 1998 and Ellis et al., 2012)
Apx Figure 8.4: Spawning and Nursery Areas Overlapping with the Site Boundary for Whiting, Spotted Ray and Spurdog (Source: Coull et al., 1998 and Ellis et al., 2012)
8.3.4 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 ICES rectangles in the south-east of Scotland provides an overview of species present within the vicinity of the Array (ICES rectangles: 40E7, 40E8, 41E7, 41E8, 41E9, 42E7, 42E8, 42E9 and 42F0, Apx Figure 8.5 Open ▸ ). Shellfish landings dominate the market in theses ICES rectangles, with 36,572 tonnes landed between 2014 to 2021, compared to 1,735 tonnes and 1,258 tonnes of pelagic and demersal fish, respectively (Marine Scotland, 2021). The value of these shellfish landings was significantly higher (£126,676,824) than that of demersal (£1,538,699) and pelagic (£1,223,787) fish between 2014 to 2021 (Marine Scotland, 2021). This high value of shellfish is primarily due to consistently high landings of Norway lobster Nephrops norvegicus (hereafter referred to as Nephrops) and medium landings of European lobster Hommarus gammarus throughout the specified ICES rectangles (Mclay et al., 2016; Mesquita et al., 2016, 2017; Marine Scotland, 2021). In 2020 for example, 1,404 tonnes of Nephrops were landed from ICES rectangle 41E7, at a value of £2,884,329, compared to only 123 tonnes of European lobster at a value of £1,555,388 (Marine Scotland, 2021).
- It should be noted that landings within ICES Rectangle 42E9, where the majority of the site boundary is located ( Apx Figure 8.5 Open ▸ ) are considerably lower than in nearby ICES Rectangles and those nearer the coast (e.g. 41E7). The shellfish species with the highest annual average landings within ICES Rectangle 42E9 between 2016 to 2021 are as follows:
- scallops: 5.9 tonnes (= £13,949);
- Nephrops: 2.6 tonnes (= £11,062);
- brown crab: 1.4 tonnes (= £3,410); and
- squid (Loligo sp.): 0.3 tonnes (= £1,335; MMO, 2022).
- Other shellfish with medium to low landings in the vicinity of the Array include crustaceans and molluscs (including cephalopods). Crustaceans include medium to low landings of brown crab Cancer pagurus and velvet swimming crab Necora puber, and low landings (< five tonnes) of common prawns Palaemon serratus, and green crab Carcinus maenas (Mesquita et al., 2016, 2017; Marine Scotland, 2021). Molluscs include medium to low landings of king scallops Pecten maximus, whelks Buccinum undatum, razor clams Solen spp., surf clams Spisula spp., clams Mya arenaria, squid Loliginidae, and octopi Ommastrephidae (Barreto and Bailey, 2013; Marine Scotland, 2021).
- During the site-specific benthic surveys conducted across the site boundary in 2022, horse mussels Modiolus modiolus were observed scattered across the south-east and along the border of the site boundary, however no M. modiolus beds were identified. Queen scallop Aequipecten opercularis were also observed, as were various non-commercial crustaceans, such as the shrimp Crangon allmanni.
- Similarly, during the epibenthic trawls conducted for Seagreen 1 (formerly known as Seagreen Alpha and Bravo) fish and shellfish study in 2011, two shellfish species were observed, king scallop and queen scallop (Seagreen, 2012, 2018). In addition, the 2020 epibenthic beam trawl surveys conducted for the Berwick Bank Offshore Wind Farm recorded Nephrops, brown crab, king scallop, brown shrimp Crangon crangon, and pandalid shrimp species (SSER, 2022). However, it should be noted that these observations were recorded further inshore than the Array.
Apx Figure 8.5: ICES Statistical Rectangles in Proximity to the Site Boundary
8.3.5 Designated Sites and Species of Conservation Importance
- Although there are no designated sites overlapping with the Array, there are several protected areas in East Scotland and north-east England for fish and shellfish ecology. These sites include SACs and one Marine Protected Area (MPA) and are provided in Apx Table 8.4 Open ▸ and Apx Figure 8.6 Open ▸ .
- Several fish and shellfish species potentially or likely to be present and/or with spawning and/or nursery grounds in the vicinity of the Array are listed as Priority Marine Features (PMF), OSPAR and Scottish Biodiversity List (SBL) species. These species are anglerfish, blue whiting, cod, herring, horse mackerel, ling, mackerel, saithe, sandeel, spurdog, whiting, and the marine life stage of Atlantic salmon, European eel, river lamprey, sea lamprey, and sea trout (Tyler-Walters et al., 2016). The PMF status of these species will also be fully considered and assessed in the fish and shellfish ecology chapter of the Offshore EIA Report.
- There were 13 species of conservation importance recorded during the site-specific benthic subtidal ecology surveys. The species included horse mussel (PMF, OSPAR, and SBL), anglerfish (PMF and SBL), cod (PMF, OSPAR, and SBL), Norway pout (PMF and SBL), plaice (SBL), saithe (PMF), sandeels (PMF and SBL), sole (SBL) and whiting (PMF and SBL). The remainder of the species were not of relevance to fish and shellfish ecology and are presented in Appendix 8.
Apx Table 8.4: Summary of Designated Sites for Fish and Shellfish Features in Proximity to the Array
Apx Figure 8.6: Sites Designated for Relevant Fish and Shellfish Features and Other Offshore Infrastructure Within Close Proximity to the Site Boundary