Fish and fisheries research to inform ScotMER evidence gaps and future strategic research in the UK: review

Evidence Gap FF.13: Cumulative pressures and impact pathways

Review of current knowledge

The assessment of cumulative effects is required through a number of legislative drivers such as EIA, Strategic Environmental Impact Assessment (SEA), Habitats Regulations Appraisal/Assessment (HRA) related regulations. However, cumulative effects are often not fully assessed due to their complexities and the lack of detailed information on proposed or existing developments and their interactions with the environment (MMO 2014b).

Frameworks to aid the assessment of cumulative effects have been developed in the UK and in other countries (e.g. MMO 2014b, Natural England 2014, Rijkswaterstaat 2019). These tend to follow the DPSIR approach which systematically identifies drivers, pressures, state, impacts and responses, and include consideration of evidence requirements in relation to activities, pressures and receptors. For example, the strategic framework for cumulative assessment developed by the MMO (2014b) includes detailed activity-pressure and pressure-receptor tables.

Despite the available guidance, assessing cumulative impacts on fish remains challenging due to the mobile nature of most species and the gaps in current knowledge on the impact of MRE developments (see Evidence Gap FF.06 to FF.12). This is of importance as understanding cumulative effects on fish species is critical to fully understand cumulative effects on other species groups (i.e. marine mammals and birds).

Modelling approaches have been used in recent years to facilitate ecosystem-based cumulative assessments (e.g. Niquil et al 2020, Nogues et al 2020, Raoux et al 2017). Existing models may be adapted to take account of different scenarios associated with the development of MRE projects, however, the improvement of knowledge gaps of the effects of MRE on fish (and shellfish) need to be progressed in parallel to maximise the utility of such models (MMO 2013b).

Next steps in research

Taking account of the findings of the literature review presented above in respect of "Evidence Gap FF.13: Cumulative impact assessments and impact pathways", the following next steps in research have been identified to address current knowledge gaps:

• Update and standardise current knowledge on cumulative pressures and impact pathways for key fish and shellfish receptors (and other inter-related receptors-benthic communities, marine mammals and birds) to allow the undertaking of consistent assessments across different projects and sectors on an UK-wide basis;
• Recommendations proposed for all other evidence gaps addressed in this report of relevance to fish and shellfish species, particularly evidence gaps FF.06 to FF.12, would also help improve the evidence base to inform cumulative assessments.