Feeding habits of the Guiana dolphin, Sotalia guianensis (Cetacea: Delphinidae), in Norte Bay, southern Brazil

摘要

The stomach contents of 18 Guiana dolphins stranded or accidentally caught by fishing around Norte Bay of Santa Catarina Island between 1990 and 2006 were examined. The small population of Guiana dolphins studied showed a varied diet, and prey was caught disproportionately. The stomach contents of these dolphins consisted of 448 prey remains coming from 18 species and 10 families. Their diet primarily consisted of fish, but also shrimp and squid. The most important species were cutlass fish (Trichiurus lepturus) and white mouth croaker (Micropogonias furnieri), which together comprised 75% of the total biomass. Although prey size ranged widely from 1.4 to 92.8 cm, a prevalence of prey smaller than 20 cm was observed. There was a predominance of prey living in moderate or large schools. The prey also had a wide vertical distribution in the water column. Our results support the opportunistic feeding habit of the Guiana dolphin, since its diverse diet was clearly guided by the availability and accessibility of resources in its habitat.