9.8. Key Parameters for Assessment

9.8.1. Maximum Design Scenario

43.               The MDSs identified in Table 9.13   Open ▸ are those expected to have the potential to result in the greatest effect on an identified receptor or receptor group. These scenarios have been selected from the details provided in volume 1, chapter 3 of the Array EIA Report. Effects of greater adverse significance are not predicted to arise should any other development scenario, based on details within the Project Description (volume 1, chapter 3) (e.g. different infrastructure layout), to that assessed here, be taken forward in the final design scheme.

 

Table 9.13:
Maximum Design Scenario Considered for Each Potential Impact as Part of the Assessment of LSE1 on Fish and Shellfish

Table 9.13: Maximum Design Scenario Considered for Each Potential Impact as Part of the Assessment of LSE1 on Fish and Shellfish

 

9.8.2. Impacts Scoped Out of the Assessment

44.               The fish and shellfish ecology pre-Scoping workshop (see Table 9.7   Open ▸ ) was used to facilitate stakeholder engagement on topics to be scoped out of the assessment.

45.               On the basis of the baseline environment and the Project Description outlined in volume 1, chapter 3 of the Array EIA Report, a number of impacts have been agreed to be scoped out of the assessment for fish and shellfish ecology. This was either agreed with key stakeholders through consultation as discussed in volume 1, chapter 5, or otherwise, the impact was proposed to be scoped out in the Array EIA Scoping Report (Ossian OWFL, 2023), and no concerns were raised by key consultees within the Scoping Opinion.

46.               These impacts are outlined, together with a justification for scoping them out, in Table 9.14   Open ▸ .

Table 9.14:
Impact Scoped Out of the Assessment for Fish and Shellfish Ecology (Tick Confirms the Impact is Scoped Out)

Table 9.14: Impact Scoped Out of the Assessment for Fish and Shellfish Ecology (Tick Confirms the Impact is Scoped Out)

 

9.9. Methodology for Assessment of Effects

9.9.1. Overview

47.               The fish and shellfish ecology assessment of effects has followed the methodology set out in volume 1, chapter 6 of the Array EIA Report. Specific to the fish and shellfish ecology EIA, the following guidance documents have also been considered:

  • guidelines for Ecological Impact Assessment (EcIA) in the UK and Ireland. Terrestrial, Freshwater and Coastal (CIEEM, 2019);
  • guidance on Environmental Considerations for Offshore Wind Farm Development (OSPAR, 2008); and
  • guidelines for data acquisition to support marine environmental assessments of offshore renewable energy projects (Judd, 2012).

9.9.2. Criteria for Assessment of Effects

48.               When determining the significance of effects, a two-stage process that involves defining the magnitude of the potential impacts and the sensitivity of the receptors. This section describes the criteria applied in this chapter to assign values to the magnitude of potential impacts and the sensitivity of the receptors. The terms used to define magnitude and sensitivity are based on those which are described in further detail in volume 1, chapter 6 of the Array EIA Report.

49.               The criteria for defining magnitude in this chapter are outlined in Table 9.15   Open ▸ . Each assessment considered the spatial extent, duration, frequency and reversibility of impact and these are outlined within the magnitude section of each assessment of effect (e.g. a duration of hours or days would be considered for most receptors to be of short term duration, which is likely to result in a low magnitude of impact).

 

Table 9.15:
Definition of Terms Relating to the Magnitude of an Impact

Table 9.15: Definition of Terms Relating to the Magnitude of an Impact

 

50.               The criteria for defining sensitivity in this chapter are outlined in Table 9.16   Open ▸ .

51.               The definitions of sensitivities of fish and shellfish IEFs have been informed by the Marine Evidence based Sensitivity Assessment (MarESA) (MarLIN, 2021) and FeAST (NatureScot, 2021). The MarESA defines sensitivity as a product of the likelihood of damage (resistance) due to a pressure and the rate of recovery (recoverability) once the pressure has been removed. Recoverability is the ability of a habitat to return to the state of the habitat that existed before the activity or event which caused change. Full recovery does not necessarily mean that every component species has returned to its prior condition, abundance, or extent but that the relevant functional components are present, and the habitat is structurally and functionally recognisable as the initial habitat of interest. The FeAST is another web based application which allows users to investigate the sensitivity of marine features in Scotland’s seas, to pressures arising from human activities (noting that this has been developed for features of low/limited mobility, so may not be relevant to fish and shellfish ecology). The FeAST sensitivity assessment considers feature tolerance (ability to absorb or resist change or disturbance) to a pressure and its ability to recover once the pressure stops. Both the MarESA and the FeAST define pressures by a benchmark which describes the extent and duration of the pressure but does not consider the intensity, frequency of pressures or any cumulative impacts. The FeAST tool has been utilised to identify pressures where possible, however, it is only available for a small number of fish and shellfish species at the time of writing.

52.               Information on sensitivity of the fish and shellfish ecology IEFs are discussed within the impact assessment according to the broad groupings set out in section 9.7.3, as in many cases sensitivities for fish and shellfish receptors to particular impacts are similar across species groupings. Where further detail on species specific sensitivities are required (e.g. for species known to be sensitive to particular impacts and/or of particular importance), these are discussed and evidenced as appropriate. For example sensitivity to habitat loss impacts may be discussed for marine fish and shellfish species in general, with further evidence presented for sandeel, which are known to be particularly sensitive to seabed impacts. For each impact, where a species is particularly sensitive to that impact this species is considered individually under its own heading. Sensitivities for other marine fish and shellfish species are presented separately to diadromous fish species. This approach has been agreed with stakeholders through the Scoping process. 

 

Table 9.16:
Definition of Terms Relating to the Sensitivity of the Receptor

Table 9.16: Definition of Terms Relating to the Sensitivity of the Receptor

 

53.               The magnitude of the impact and the sensitivity of the receptor are combined when determining the significance of the effect upon fish and shellfish ecology. The particular method employed for this assessment is presented in Table 9.17   Open ▸ .

54.               Where a range is suggested for the significance of effect, for example, minor to moderate, it is possible that this may span the significance threshold. The technical specialist’s professional judgement was applied to determine which outcome defines the most likely effect, which took in to account the sensitivity of the receptor and the magnitude of impact. Where professional judgement was applied to quantify final significance from a range, the assessment has set out the factors that result in the final assessment of significance. These factors may include the likelihood that an effect will occur, data certainty and relevant information about the wider environmental context.

55.               For the purposes of this assessment:

  • a level of residual effect of moderate or more will be considered a ‘significant’ effect in terms of the EIA Regulations; and
  • a level of residual effect of minor or less will be considered ‘not significant’ in terms of the EIA Regulations.

56.               Effects of moderate significance or above are therefore considered important in the decision-making process, whilst effects of minor significance or less warrant little, if any, weight in the decision-making process.

 

Table 9.17:
Matrix Used for the Assessment of the Significance of the Effect

Table 9.17: Matrix Used for the Assessment of the Significance of the Effect

 

9.9.3. Designated Sites

57.               This fish and shellfish ecology EIA chapter assesses the LSE1 in EIA terms on the qualifying interest feature(s) of Natura 2000 sites (i.e. nature conservation sites in Europe designated under the Habitats or Birds Directives[4]) and/or sites in the UK that comprise the National Site Network (collectively termed ‘European sites’) as described within section 9.7.2 of this chapter. The RIAA for the Array includes the assessment of the potential impacts on the site itself. A summary of the outcomes reported in the RIAA is provided in (Ossian OWFL, 2024).

58.               Where locally designated sites and national designations (other than European sites) fall within the boundaries of a European site and where qualifying interest features are the same, only the assessment on the European site is presented. Potential impacts on the integrity and conservation status of the locally or nationally designated site on the relevant qualifying interest features would be synonymous with the assessment of the European site so a separate assessment for the local or national site is not presented.

59.               However, assessment of the LSE1 on a local or nationally designated site which falls outside the boundaries of a European site, but within the fish and shellfish ecology study area, has been undertaken within this chapter using the EIA methodology.