Scottish Marine and Freshwater Science Vol 11 No 12

Offshore renewables have the potential to make a significant contribution to the Scottish Government’s target to generate 50% of Scotland's overall energy consumption from renewable sources by 2030 and to have decarbonised the energy system almost completely by 2050. The offshore wind industry is set to expand substantially in Scotland and the rest of the UK over the next decade and beyond as both the Scottish and UK Governments strive for clean energy and climate change targets, and a green economic recovery.

In May 2018, Crown Estate Scotland unveiled proposals to lease the seabed to encourage a new generation of offshore wind projects in Scotland’s waters, and ScotWind launched on 10 June 2020. To inform the spatial development of this leasing round, Marine Scotland, as Planning Authority for Scotland’s Seas, is currently developing the Sectoral Marine Plan for Offshore Wind (SMP). This plan will identify sustainable options for future commercial scale offshore wind developments. ScotWind applications must be sited within finalised Plan Option Areas identified by the Adopted SMP. Any changes to leasing arrangements needed to reflect changes between the draft and Adopted Plan will be addressed in Crown Estate Scotland ‘Post-Adoption Addendum to ScotWind Leasing’ (to be published by Crown Estate Scotland shortly after the Adopted SMP becomes available).

The construction, operation and decommissioning of renewable energy devices, such as offshore wind farms, has the potential to impact sensitive marine species such as marine mammals, which are protected in Scotland under various pieces of legislation e.g. EU Habitats Directive, Marine (Scotland) Act 2010. A key requirement in understanding and mitigating any potential impacts on these animals is ascertaining how many individuals there are, which areas they use and when they are present.

This project, undertaken by SMRU Consulting and funded by the Scottish Government and Crown Estate Scotland, consolidates marine mammal abundance and distribution estimates derived from data collected by local, regional, national and international partners. Data sources include visual (aerial, land-based and vessel-based) surveys, static and towed acoustic monitoring and animal-borne telemetry. Data originate from published and unpublished sources. The report covers all species of marine mammal commonly occurring in Scottish waters (17 species in total) and will provide important baseline information to inform marine spatial planning in Scottish waters.

The report provides a thorough review of each data source used, before exploring all known abundance and distribution estimates available for each species. A further chapter provides up-to-date information on species vital rates (e.g. survival and reproduction) where known, to allow parameterisation of population models used in impact assessments. In the final chapter, all known density estimates of each species for each of the Scotwind Leasing Draft Plan Option (DPO sites) are aggregated. Five appendices accompany the report, detailing:
i. summary of data sources used in the report,
ii. summary tables of marine mammal vital rates for species,
iii. the results of the SCANS surveys (in particular, SCANS III),
iv. updated seal at-sea usage maps, and
v. density estimates for each Draft Plan Option sites.

This work represents the most comprehensive review of its kind for marine mammal baseline information in Scottish waters, bringing together a diverse dataset from key sources to provide important geospatial and demographic information for cetaceans and seals. This information will be crucial in future licensing and consenting of marine renewable energy projects and to guide mitigation measures.