Scottish Animal Welfare Commission - proximity of seals to farmed fish: response to Marine Scotland

SAWC project: data sources

Evidence was gathered from several sources as part of the project. Firstly, a literature review was carried out to determine what evidence was available for the effects of seals on salmon and the role that ADDs play in preventing damage. The review indicated that there were significant gaps in the scientific knowledge base. While there were some data from a report in 2010 (12) on fish mortalities attributable to seals, there were few current data. In particular, there was very little information on the whether the fish may suffer from stress due the close proximity of seals to sea pens (of passing or ‘patrolling’ seals), which could lead to negative effects on fish welfare, leading to increased susceptibility to disease or impaired growth and development, and ultimately to economic losses.

A survey of Scottish finfish industry groups and relevant NGOs was then carried out in September/October 2021 to attempt to gather this information directly. The survey asked for evidence or informed opinion on the effects of direct seal attacks on sea pens, the effects of seal presence on fish behaviour, feeding and disease rates and the perceived efficacy of ADDs or alternatives in deterring seals. Three producer organisations, three NGOs, the APHA and a researcher responded to the survey and provided informative responses (see Appendix 1 for a list of respondents). However, there were still unanswered questions about current ADD design and potential effects on wildlife and efficacy, so a series of interviews with experts was held to address these topics.