Co-occurrence of seal foraging behaviour and offshore set-net fisheries in the north-east Atlantic

This study examined the overlap between grey seal (Halichoerus grypus) foraging behavior and offshore set-net fisheries using tracking data from 164 individuals tagged across the UK, Ireland, and France. Grey seals were more likely to transition from travelling to foraging behavior in or near areas with high fishing activity. This relationship was stronger in male grey seals compared to females. However, only 4.5% of recorded foraging activity occurred within 5 km of potential set-net locations, and 33-41% of seals that passed within 5-10 km of fishing activity did not switch to foraging behavior. These findings suggest that seals encounter nets opportunistically while foraging in areas that are also targeted by set-net fisheries, rather than actively seeking out fishing gear. The results provide important context for understanding seal-fishery interactions and support the use of targeted management measures, including deterrents, gear modifications, operational adjustments, and area closures to reduce opportunistic net attendance and mitigate associated conflicts such as depredation and bycatch.