Study on mitigation measures to minimise seabird bycatch in gillnet fisheries

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The incidental capture of non-target marine animals in fishing gear, such as seabirds, cetaceans, elasmobranchs, and turtles, is commonly referred to as ‘incidental bycatch’. Seabird bycatch in bottom set gillnet fisheries (GNS) is known to be a major conservation issue both globally and within Europe; an estimated 76,000 birds are caught annually in the Baltic Sea alone (Žydelis et al. 2013). Diving seabirds, such as seaducks, auks, divers, grebes and cormorants are particularly susceptible to capture in this gear. Gillnets, made of thin nylon twine, are essentially invisible under water, and diving birds are presumably not able to perceive the net whilst foraging at depth, becoming entangled and drowning. This particular fishing gear is used extensively across Europe, with both small and large-scale fleets operating in EU member states’ waters. Click here to read more

Looming Eye Research – Abstract ‘Bycatch of seabirds in gillnet fisheries is a global conservation issue with an estimated 400 000 seabirds killed each year. To date, no underwater deterrents trialled have consistently reduced seabird bycatch across operational fisheries. Using a combination of insights from land-based strategies, seabirds’ diving behaviours and their cognitive abilities, we developed a floating device exploring the effect of large eyespots and looming movement to prevent vulnerable seabirds from diving into gillnets. Here, we tested whether this novel above-water device called ‘Looming eyes buoy’ (LEB) would consistently deter vulnerable seaducks from a focal area. We counted the number of birds present in areas with and without LEBs in a controlled experimental setting. We show that long-tailed duck Clangula hyemalis abundance declined by approximately 20–30% within a 50 m radius of the LEB and that the presence of LEBs was the most important variable explaining this decline. We found no evidence for a memory effect on long-tailed ducks but found some habituation to the LEB within the time frame of the project (62 days). While further research is needed, our preliminary trials indicate that above-water visual devices could potentially contribute to reduce seabird bycatch if appropriately deployed in coordination with other management measures. Click here to read this paper