%0 Journal Article
%T Bycatch of franciscana dolphins Pontoporia blainvillei and the dynamic of artisanal fisheries in the species' southernmost area of distribution
%A Mar¨ªa Fernanda Negri
%A Pablo Denuncio
%A Mar¨ªa Victoria Panebianco
%A Humberto Luis Cappozzo
%J Brazilian Journal of Oceanography
%D 2012
%I Universidade de S?o Paulo
%R 10.1590/s1679-87592012000200005
%X In Argentina, the franciscana dolphin is one of the most vulnerable cetaceans regularly entangled in coastal artisanal fishery nets. The aim of this paper is to estimate the species' incidental mortality on the Southern coast of Buenos Aires province through interviews with the captains of artisanal fishing vessels, in the period 2006-2009. Franciscana bycatch was reported for gillnets and shrimper gear all year round but it occurred more frequently between October and February, at 5 km offshore and 10-20 m depth. The estimated mean annual incidental mortality was 107 dolphins (CI 95% = 87-129), 92 caught in gillnets (CI 95% = 73-112) and 15 in shrimpers' gear (CI 95% = 8-25) with a capture per unit effort of 0.029 dolphins per km of gillnet (CI 95% = 0.023-0.036) and 0.022 per shrimpe r's net (CI 95% = 0.012-0.035). Annual fluctuations were due to differences in the number of gillnetting fishing days. If mortality estimates for the Northern coast are also taken into account, values attain a maximum of 360-539 dolphins bycaught in the entire Buenos Aires province, representing 2.5-3.7% of the species' abundance in Argentina. This will inevitably lead to the decline of franciscana dolphin populations in the near future unless alternative fishing grounds are identified and alternative gearadopted. Na Argentina, a toninha ¨¦ um dos cet¨¢ceos mais vulner¨¢veis devido ¨¤s capturas por rede de pesca artesanal. O presente estudo teve como objetivo estimar as capturas acidentais no sul da prov¨ªncia de Buenos Aires, atrav¨¦s de entrevistas aos capit es de barcos de pesca artesanal, entre os anos 2006-2009. As capturas foram reportadas para redes de emalhe e de camar o; com as mais altas frequ¨ºncias entre outubro e fevereiro, a 5 km da costa e 10-20 m de profundidade. A mortalidade acidental m¨¦dia anual estimada foi de 107 golfinhos (IC 95% = 87-129), 92 em redes de emalhe (IC 95% = 73-112) e 15 em redes de camar o (IC 95% = 8-25), com uma captura de 0,029 golfinhos/km de rede de emalhe (IC 95% = 0,023-0,036) e 0,024/rede de camar o (IC 95% = 0,012-0,035). As flutua  es anuais responderam principalmente ¨¤s diferen as nos dias de pesca. Considerando o ¨²ltimo levantamento estimativo feito para o norte costeiro da prov¨ªncia, estima-se uma mortalidade entre 360-539 golfinhos/ano em toda a prov¨ªncia de Buenos Aires. Esses valores correspondem de 2,5-3,7% da abundancia populacional da Argentina; o que traria como consequ¨ºncia um decl¨ªnio populacional da esp¨¦cie, tornando-se fundamental encontrar alternativas de pesca para a ¨¢rea.
%K Toninha
%K Pontoporia blainvillei
%K Capturas acidentais
%K Pesca artesanal
%K Atlantico Sul-Ocidental
%K Franciscana dolphin
%K Pontoporia blainvillei
%K Incidental mortality
%K Artisanal fisheries
%K Southwestern Atlantic Ocean
%U http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1679-87592012000200005