9.7. Baseline Environment
9.7.1. Overview of Baseline Environment
Marine fish and shellfish species
21. The following sections provide a summary of the fish and shellfish ecology baseline environment. The fish and shellfish Technical Report (volume 3, appendix 9.1) includes full details of the analysis undertaken to develop the fish and shellfish ecology baseline characterisation, including results of site-specific surveys. The fish and shellfish ecology receptors that could be potentially impacted by the Array have been determined by the desktop review of available data and information as detailed in Table 9.8 Open ▸ , and through site-specific surveys, as detailed in Table 9.9 Open ▸ (see volume 3, appendix 9.1 for further detail regarding baseline data collection and site-specific surveys). The baseline environment was described for the fish and shellfish ecology study area, which encompasses the Firth of Forth (see Figure 9.1 Open ▸ ). Baseline data sources cover a broad spatial and temporal scale, making use of data collected using a range of methods. The baseline presented is therefore considered to represent a comprehensive and robust description of likely fish and shellfish species that could be present within the vicinity of the site boundary and fish and shellfish study area.
22. The following species were identified as those key fish and shellfish receptors likely to be found within the fish and shellfish ecology study area, representing the most commonly found species in the area. Based on the baseline information a subset of ecologically and commercially important species have been carried forward as IEFs for the purposes of EIA (see section 9.7.3):
- demersal species – cod Gadus morhua, haddock Melanogrammus aeglefinus, whiting Merlangius merlangus, plaice Pleuronectes platessa, lemon sole Microstomus kitt, ling Molva molva, saithe Pollachius virens and sandeel Ammodytes spp;
- pelagic species – herring Clupea harengus, mackerel Scomber scombrus and sprat Sprattus sprattus;
- elasmobranch species – spotted ray Raja montagui, thornback ray Raja clavata, tope shark Galeorhinus galeus, small-spotted catshark Scyliorhinus canicula, spurdog Squalus 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).
- diadromous species – Atlantic salmon, sea trout, river lamprey Lampetra fluviatilis (inshore areas only), sea lamprey Petromyzon marinus, European eel Anguilla anguilla, allis shad Alosa alosa, twaite shad Allosa fallax, and freshwater pearl mussel Margaritifera margaritifera (included here due to reliance on Atlantic salmon and sea trout at specific life stages); and
- shellfish species – pink shrimp Pandalus borealis, Nephrops, edible crab Cancer pagurus, king scallop Pecten maximus, European lobster Homarus gammarus, brown shrimp Crangon crangon, velvet swimming crab Necora puber, queen scallop Aequipecten opercularis, cockle Cerastoderma edule, blue mussel Mytilus edulis, common whelk Buccinum undatum (referred to as whelk hereafter), and squid (Loliginidae spp. and Ommastrephidae spp.).
23. The spawning and nursery habitats present within the site boundary are summarised in Table 9.10 Open ▸ based on Ellis et al. (2012) and Coull et al. (1998). Nursery and spawning habitats were categorised by Ellis et al. (2012) as either high or low intensity dependent on the level of spawning activity or abundance of juveniles recorded. Spawning grounds identified by Coull et al. (1998) are classified as low, high or undetermined, again based on the level of spawning activity. Intensity of nursery grounds were not specified by Coull et al. (1998). Further detail on nursery and spawning grounds is presented in volume 3, appendix 9.1.
Table 9.10: Key Species with Spawning and Nursery Grounds which Overlap with the Site Boundary
Herring
24. Herring utilise specific benthic habitats during spawning, which increases their vulnerability to activities impacting the seabed. Further, as a hearing specialist (Popper et al., 2022), herring are vulnerable to impacts arising from underwater noise. Figure 9.2 Open ▸ illustrates site-specific survey data alongside EMODnet seabed substrate data. This figure shows the site boundary as characterised unsuitable habitat for herring to spawn. Preferred habitats are located directly north of the site boundary, in line with spawning grounds from Coull et al. (1998).
25. As displayed by Figure 9.2 Open ▸ the spawning ground adjacent to the north-west of the site boundary identified by Coull et al. (1998) has recorded persistently high levels of spawning activity with relatively little variation from 2007 to 2016. The spawning area identified to the south-west of the site boundary has had variable spawning levels from 2007 to 2016. Due to lack of IHLS survey data between 2017 and 2018, and a change in reporting strategy from IHLS, since 2019, more recent herring larvae data were not available for analysis. However, an ICES scientific report (ICES, 2021) noted that IHLS data for 2019 to 2020 in the Buchan area (where an autumn spawning stock exists off the north-east coast of Scotland) was in the same order of magnitude as previous years (Boyle and New, 2018), therefore, it can be assumed that there are no significant changes from the results presented for 2007 to 2016 outside of normal annual variations. The highest concentrations of herring larval abundances are localised off the coast of Peterhead, which do not extend throughout the undetermined intensity spawning grounds of Coull et al. (1998) (see Figure 9.2 Open ▸ ). This is supported by the habitat suitability data from both site-specific sampling effort and broadscale EMODnet seabed substrates (following classifications in Reach et al., 2013), as shown in Figure 9.2 Open ▸ .
Sandeel
26. Raitt’s sandeel Ammodytes marinus and lesser sandeel Ammodytes tobianus are Scottish PMFs. Sandeel behaviour limits the habitat that sandeel can occupy to areas of very specific sediment particle sizes, where penetration into the sediment is possible. Figure 9.4 Open ▸ presents the results of site-specific PSA survey data alongside EMODnet seabed substrate data which can be used to assess habitat suitability for sandeel.
27. For the purposes of considering sandeel habitat, suitability across the fish and shellfish ecology study area and surrounding areas, ‘gravelly sand’, ‘(gravelly) sand’, and ‘sand’ in the EMODnet data were classified as preferred habitat and ‘sandy gravel’ as marginal habitat (see volume 3, appendix 9.1 for further details on these classifications). The EMODnet data suggests that the whole site boundary is covered by slightly gravelly sand, which is a preferred habitat for sandeel ( Figure 9.4 Open ▸ ). However, the site-specific survey data show the north-west portion as preferred and marginal habitat and south-east as a mosaic of unsuitable and marginal habitat. These data highlight a degree of fine-scale variation that is not possible to resolve when working with broadscale data alone and highlights the patchy nature of sandeel habitat within the site boundary.
28. The north-west section of the site boundary is mostly characterised by marginal and preferred habitats, while the south-east is covered by patches of unsuitable and marginal habitat, according to Latto et al. (2013) criteria ( Figure 9.4 Open ▸ ). Abundance data from grab sampling and epibenthic trawls within the site boundary also indicated higher abundances of sandeel in the north-west section of the site boundary which aligns with the composition of the sediments (see volume 3, appendix 9.1 for further detail).
29. Figure 9.4 Open ▸ presents the outputs of predicted distribution modelling by Langton et al. (2021) within the site boundary and shows that the whole site boundary has extremely low probability of sandeel presence, with areas where predicted density is high closer to the coasts or towards the Firth of Forth.
Figure 9.2: Herring Spawning Habitat Preference Classifications from EMODnet and Site-specific Survey Data
Figure 9.3: Herring Cumulative Larval Density from IHLS Data Sets from 2007 to 2016
Figure 9.4: Sandeel Habitat Classification from EMODnet, Latto et al. (2013), and Site-specific Survey Data
Figure 9.5: Model Derived Predictions of Density and Probability of Presence of Sandeel within the Site Boundary (Derived from Langton et al. 2021)
9.7.2. Designated Sites
30. Designated sites and relevant qualifying interest features identified for the fish and shellfish ecology Array EIA Report chapter are described in Table 9.11 Open ▸ and presented in Figure 9.6 Open ▸ .
Table 9.11: Designated Sites and Relevant Qualifying Interest Features for the Fish and Shellfish Ecology Array EIA Report Chapter
Figure 9.6: Fish and Shellfish Ecology Relevant Designated Sites
9.7.3. Imporant Ecological Features
31. For the purposes of the fish and shellfish ecology Array EIA chapter IEFs have been identified using good practice guidelines (Chartered Institute of Ecology and Environmental Management (CIEEM), 2019). The potential impacts of the Array which have been scoped into the assessment (see section 9.8) have been assessed against the IEFs to determine whether or not they are likely to be significant, therefore, the IEFs assessed are those that are considered to be important and potentially impacted by the Array. Importance may be assigned due to quality or extent of habitats, habitat or species rarity or the extent to which they are threatened (CIEEM, 2019). For a species or habitat to be considered an IEF, they must have a specific biodiversity importance recognised through international or national legislation or through local, regional, or national conservation plans (e.g. Annex I habitats under the Habitats Directive, Convention for the Protection of the Marine Environment of the North-East Atlantic (OSPAR), National Biodiversity Plan or the Marine Strategy Framework Directive, Scottish PMFs and the Scottish Biodiversity list). In addition, the commercial importance of fish and shellfish receptors is considered when assigning importance of IEFs within the fish and shellfish ecology study area, drawing on information presented in commercial fisheries baseline characterisation (volume 3, appendix 12.1).
32. As requested by NatureScot ( Table 9.7 Open ▸ ), IEFs have been identified based on a range of factors, including their importance as PMFs, their ecological importance (e.g. as prey species) and the importance of the fish and shellfish study area at particular life history stages (e.g. spawning, nursery and migration).
33. Table 9.12 Open ▸ lists all the IEFs within the fish and shellfish ecology study area, by applying the defining criteria summarised in paragraph 31 (see volume 3, appendix 9.1 for further detail).
Table 9.12: IEFs within the Fish and Shellfish Ecology Study Area
9.7.4. Future Baseline Scenario
35. If the Array does not come forward, a description of the ‘without development’ future baseline conditions has also been carried out and is described within this section.
36. The baseline environment is not static and will exhibit some degree of natural change over time, even if the Array does not come forward, due to naturally occurring cycles and processes and additionally any potential changes resulting from climate change (refer to volume 2, chapter 17 for further detail). Therefore, when undertaking assessments of LSE1, it will be necessary to place any potential impacts into the context of the envelope of change that might occur over the timescale of the Array.
37. Further to potential change associated with existing cycles and processes, it is necessary to consider the potential effects of climate change on the marine environment. Variability and long term changes on physical influences may bring direct and indirect changes to fish and shellfish populations and communities in the mid to long term future (Heath et al., 2012).
38. Scottish and UK waters are facing an increase in sea surface temperature. The rate of increases is varied geographically, but between 1985 and 2009, the average rate of increase in Scottish waters has been greater than 0.2°C per decade, with the south-east of Scotland having a higher rate of 0.5°C per decade (Marine Scotland, 2011). A study completed over a longer period showed Scottish waters (coastal and oceanic) have warmed by between 0.05 and 0.07°C per decade, calculated across the period 1870 to 2016 (Hughes et al., 2018). Changes in temperature will have an effect on fish and shellfish at all biological levels (cellular, individual, population, species, community and ecosystem) both directly and indirectly. As sea temperatures rise, species adapted to cold water (e.g. cod and herring) will begin to disappear while warm water adapted species will become more established. It is also predicted that due to changes in weather patterns, for example increased numbers of spring storms, changes in stratification of water columns and plankton production may occur (Morison et al., 2019). This may cause knock on impacts on fish and shellfish species due to changes in food availability for prey species. Climate change presents many uncertainties as to how the marine environment will change in the future.
39. Furthermore, fisheries management measures, may also affect fish and shellfish species, communities and habitats in the fish and shellfish ecology study area. This includes the recent closure of sandeel fisheries in Scottish waters (i.e. The Sandeel (Prohibition of Fishing) (Scotland) Order 2024) which will see a ban on the fishing for sandeel from March 2024 within the Scottish zone. It is anticipated that this closure will provide wider potential benefits to the marine ecosystem including direct benefits to sandeel populations (through reduction of pressures from fishing) and indirect benefits to a wide range of fish, seabird and marine mammal species, as sandeel is an important prey species for a wide range of species in the marine ecosystem.
40. Any changes that may occur during the design life span of the Array should be considered in the context of both greater variability and sustained trends occurring on national and international scales in the marine environment.
9.7.5. Data Limitations and Assumptions
41. The data sources used in this chapter are detailed in Table 9.8 Open ▸ and volume 3, appendix 9.1. The desktop data used are the most up to date publicly available information which can be obtained from the applicable data sources as cited. Data that has been collected is based on existing literature, consultation with stakeholders, identification of habitats and site-specific survey data. This has been used to inform likely fish and shellfish species and communities and their associated habitats within the fish and shellfish ecology study area.
42. Site-specific surveys, including grab sampling and epibenthic trawls, were carried out to characterise the benthic subtidal ecology within the site boundary (volume 2, chapter 8), and did not specifically target fish and shellfish species. As a result, some species may have been missed. However, commercial fisheries information has been incorporated into the baseline characterisation, which itself was informed by consultation with the fishing industry, as presented in volume 2, chapter 12. As such, this additional information will have filled any gaps missed through site-specific surveys. These surveys provided opportunistic additional fish and shellfish data which have been incorporated into the assessment. However, given the detailed desktop study completed, covering a long time series and a wide variety of information sources (e.g. including scientific literature, grey literature, commercial fisheries information) and the conservative approach adopted, it is unlikely that key species have been omitted from the assessment.