Interactions between subantarctic fur seal ( Arctocephalus tropicalis) and cookiecutter shark ( Isistius plutodus) on the coast of Bahia, north-eastern Brazil

Abstract

The predation of pinnipeds by sharks in tropical or temperate regions is a significant cause of mortality of this group and little is known about these interactions off the Brazilian coast, since the records of these species are occasional, mainly in the north-eastern region. The objective of this study is to report the predator–prey interactions between sub-Antarctic fur seal (Arctocephalus tropicalis) and cookiecutter shark (Isistius brasiliensis) off the coast of Bahia. The present study was based on numbers of pinnipeds stranded, where there had been observed two specimens of sub-Antarctic fur seal, A. tropicalis. The diagnostic identification of shark predators was through the analysis of the morphology and conditions of the wounds compared with specialized literature. The measures are fit in category III, to whose height and width they are similar, suggesting to have been inferred for I. plutodus. This study confirms the necessity for continuing to study the interactions between sharks and pinnipeds in order to better understand the predator–prey relations off the Brazilian coast, as well as to question the extent to which these interactions cause the hindrance of this group.