Seabird bycatch in demersal longline fisheries off southeast and southern Brazil

Seabird bycatch in DLL fisheries is well documented worldwide. However, information gaps for several fleets, including the Brazilian fisheries, remains a challenge for fully understanding the global impact of DLL fisheries on seabirds, as well as to identify target fleets for management actions. Here we assessed seabird bycatch in Brazilian DLL fisheries using detailed set-by-set information on fishing operations and seabird bycatch voluntary self-reported by skippers between November 2017 and December 2019, in three ports across southern (Rio Grande-RS and Itajaí-SC) and southeast Brazil (Cabo Frio-RJ). The total dataset includes 109 fishing trips, 2,031 sets and nearly 4 million hooks. For the Southern fleet, a total of 33 seabirds were reported caught (BPUE = 0.02), while for Southeast fleet, 263 seabirds were reported (BPUE = 0.14). In the estimate of global seabird bycatch in longline fisheries conducted by Anderson et al. (2011), Brazilian DLL fisheries was assumedly collapsed. However, our results not only show that this fishery has continuously operated since the 90s, but also that the current annual seabird mortality (mean = 7,730 birds) is much higher than previously estimated, roughly 4,000 birds per year. The current high bycatch levels in DLL fisheries off southern and southeast Brazil represent a pervasive and cumulative threat to albatrosses and petrels already imperilled by bycatch in pelagic longline fisheries. Therefore, a management plan for monitoring and addressing seabird bycatch in these fisheries is urgently needed to reduce the fisheries-related mortality of threatened seabirds in the Southwest Atlantic Ocean.