Diet composition of franciscana dolphin Pontoporia blainvillei from southern Buenos Aires, Argentina and its interaction with fisheries

Abstract

The present study provides information about prey species consumed by franciscana dolphin, Pontoporia blainvillei, from southern Buenos Aires coast in Argentina. We collected 66 franciscana dolphins between 2003 to 2011 incidentally entangled in the artisanal fishing nets. We analyzed the stomach contents and estimated prey size in order to evaluate size overlapping with fisheries. Although remains corresponded to 11 prey species, only two were important in the diet, the striped weakfish, Cynoscion guatucupa, and the squid, Loligo sanpaulensis. Almost all prey present in the diet are of commercial interest. The overlapping of target species and prey that are subject to overfishing could enhance the vulnerability of franciscana by reducing food availability.