Buoys with looming eyes deter seaducks and could potentially reduce seabird bycatch in gillnets

• Main Authors: Yann Rouxel, Rory Crawford, Ian R. Cleasby, Pete Kibel, Ellie Owen, Veljo Volke, Alexandra K. Schnell, Steffen Oppel
• Format: Article
• Language: English
• Published: The Royal Society 2021-05-01
• Series: Royal Society Open Science
• Subjects: gillnet; bycatch; seabirds; deterrent; mitigation measures; marine conservation
• Online Access: https://royalsocietypublishing.org/doi/10.1098/rsos.210225

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.