Magellanic Penguin diet requirements and its relationship with commercial fisheries: a case study in Golfo San Jorge, Patagonia Argentina

GONZÁLEZ ZEVALLOS, DIEGO; YORIO, PABLO; BIAGIONI, OSCAR; GATTO, ALEJANDRO

Valparaiso

Conferencia; II Rufford Small Grant Conference, Sudamérica; 2015

The Rufford Foundation

Aspects related to the abundance, biomass and the role of the Magellanic Penguin (Spheniscus magellanicus) as top predator, position it as an important component of coastal and marine ecosystems. Although one quarter of the Patagonian population of this species breeds along the northern coast of Golfo San Jorge, recently included in the Patagonia Austral Marine Park, the composition of its diet is still unknown. This study analyzes the diet composition of Magellanic Penguins complementing two methodologies, stomach lavage and stable isotope analysis, during the breeding season 2011-2012 in colonies located in the North Vernacci Islands (45°11'S, 66°30'W). Samples were taken in the early and late chicks stages (chicks younger and older than 30 days, respectively). Through the analysis of stomach samples, a total of 1870 prey items were recorded and at least 14 species were identified, including 8 species of fish, 3 of cephalopods and 3 of crustaceans. The Anchovy (Engraulis anchovy) was the prey with the higher relative  importance index value in both stages of the reproductive cycle (88.4 and 54.1%) followed by squid (Illex argentinus) in the second stage (24.5%). Stable isotope analysis confirmed the results obtained using stomach lavage. The recent interest in developing an Anchovy fishery in the study area suggests the need for more information to assess the potential impact of the extractive activity on Magellanic penguin populations.