Traditional knowledge identifies causes of bycatch on bottlenose dolphins (Tursiops truncatus Montagu 1821): An ethnobiological approach

Studies have documented the importance of understanding the traditional knowledge of artisanal fishermen regarding fishery-cetacean interactions. In this paper, we identified the effects of artisanal fisheries on bottlenose dolphins (Tursiops truncatus) in southern Brazil (∼30°S - 32°S) and searched for alternatives to decrease the possible negative effects based on fishermen's knowledge. In November and December 2009, 44 interviews were conducted with fishermen who worked in the Barra de Imbé/Tramandaí (n = 22) and in the southern part of the Lagoa dos Patos in Rio Grande (n = 22). There is an overlap between bottlenose dolphin distribution and fishery activities, which could cause an increase in bycatch frequency. According to local fishermen, more rigorous laws must be enacted to prevent entanglement. The employment of acoustic alarms in gillnets to reduce the frequency of bycatch is not well accepted because there is a widespread fear of causing a decrease in fishing efficiency.