A long term program on South American Sea Lion of Argentina

CAPPOZZO, H.L.

Abstracts Sea Lions of the World

NOAA and Sea Grant Alaska

Lugar: Anchorage, Alaska; Año: 2004 p. 122 - 122

This presentation aims at updating the information about the behavior, genetics and diet of the South American Sea Lion, Otaria flavescens, in relation with this species? interaction with commercial fisheries. This species is distributed along the Atlantic and Pacific coasts of South America. Total population has recently been estimated at 110,000 for the Southwestern Atlantic coast, mainly concentrated at the Patagonian coast and southern islands. Along the coast of the province of Buenos Aires, Argentina, there has been a great reduction of habitat because of the human use of the zone. Our program comprises studies conducted at Buenos Aires?s province and Patagonian coasts since the past decade. There is little information regarding migrations and seasonal movements. We started the analysis of the genetic variability by comparing two groups (Uruguay vs. Northern Patagonia), and the results suggest that they belong to the same population. The rookeries of Buenos Aires presented mainly subadult and/or adult males, which interact with the coastal fisheries, supposedly causing some damage to nets and competing over preys. In our seasonal study of the diet, we determined that sea lions prey mainly on finfishes and secondarily on cephalopods. The main prey on the area of Puerto Quequén is Raneya fluminensis, a non-commercial species, although other preys may be of commercial use. These results suggest that there may be some interference or biological interaction between the sea lions and the fishing fleet. This update highlights the need of understanding the behavior in other rookeries, analyzing the genetics of the other groups of the southwestern Atlantic in order to determine the variability of the population, and obtaining more information about operational interactions with commercial fishing. We consider all this a fundamental basis for outlining a coherent management policy, and are subject of our research program.