First observations of operational interactions between bottom-trawling fisheries and South American sea lion, <i>Otaria flavescens</i> in south-central Chile

Abstract

This paper presents results of a study conducted on the trawling industrial fishery fleet of Merluccius gayi in south-central Chile, and the resulting interactions with the South American sea lion (Otaria flavescens) . This study is based on observations made during September 2004, when incidental sea lion catch in the trawls was 6.3 sea lions/working day (1.2 sea lions/trawl −1 ). A total of 82 animals were incidentally caught, of which 12 were found dead, and the 70 remaining suffered from internal bleeding and/or fractures as a result of their capture. 83.3% of the fatalities occurred during nocturnal trawls, which comprise 30% of all observed trawls. Possible mechanisms of sea lion take are discussed. This note presents the first records of sea lions incidental by-catch by the trawler fleet along the south-east Pacific coast of Chile.