Seasonal movements of the south american sea lion (otaria flavescens, shaw) off the rio grande do sul coast, brazil

Abstract

From 1977 to 1986, 292 dead specimens of Otaria flavescens (synonymy O. byronia) found between Hermenegildo (33°40'S) and Barra do Estreito (31°51'S) in southern Brazil were examined. From April 1985 to May 1986 observations were conducted on hauled-out individuals on the eastern jetty at Lagoa dos Patos (32°10'S). Sea lions apparently move north from rookeries in Uruguay after the breeding season. Most animals (81 %) were males, represented mainly by immature individuals. Females were mainly adults. The species is present on the Rio Grande do Sul coast in large numbers from April to June. The extremity of the eastern jetty is a resting area for males, with larger numbers being observed early in the morning, decreasing during the day and increasing again in the evening. Although females were observed on the jetty, no reproductive activity was noted. Of the 292 carcasses analysed, 29.8 % presented signs of interaction with fisheries. Instances of aggressive behaviour from fishermen towards sea lions were recorded. © 1994, Walter de Gruyter. All rights reserved.