‘Human-dolphin ( Tursiops truncatus Montagu, 1821) cooperative fishery’ and its influence on cast net fishing activities in Barra de Imbé/Tramandaí, Southern Brazil

Abstract

‘Human-dolphin ( Tursiops truncatus Montagu, 1821) cooperative fishery’ and its influence on cast net fishing activities in Barra de Imbé/Tramandaí, Southern Brazil – aims to describe ‘fishing with dolphins’ or ‘ botos’ ( Tursiops truncatus Montagu, 1821), its importance in mullet fishing in conjunction with the traditional knowledge of artisanal fishermen, and the negative economic impact that tourism has had on mullet fishing in Barra de Imbé/Tramandaí (29°58′S 50°07′W). In November and December of 2009, 22 artisanal fishermen associated with the Tramandaí Fishermen’s Union were interviewed. During these interviews, questionnaires were employed utilizing both open and closed questions that dealt with behavioral ecology, biological and interactional issues related to bottlenose dolphins, and small-scale fishing in the region. All those interviewed described “ boto fishing,” in which bottlenose dolphins “helped out the fishermen.” According to these interviews, this kind of fishing, marked by close interaction between humans and ‘ botos,’ allows nets to be cast fewer times and with captured fish yields that are greater than, when there is no dolphin is present. The fishermen maintain that this increased productivity results from ‘ botos’ showing them exactly where the schools of fish are located below the water surface. This has made it possible to observe the impact that dolphin fishing has on the monthly incomes of these fishermen, and there is concern among fishermen, that the intense tourism may one day contribute to the disappearance of the ‘ boto,’ a situation, they believe would negatively affect their fishing activities.