Diet of the Neotropic Cormorant Phalacrocorax olivaceus at West Chubut, Patagonia, Argentina

A total of 124 pellets (regurgitated casts) produced by the Neotropic Cormorant (Phalacrocorax olivaceus) were collected monthly between January 2004 and November 2005 from a roosting site at Rosario Lake Chubut, Patagonia, Argentina. Analyses of the samples showed that fish were the most frequent a...

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Bibliographic Details
Published in:Waterbirds
Main Authors: Casaux, Ricardo Jorge, Di Prinzio, Cecilia Yanina, Bertolin, María Lila, Tartara, Maria Alejandra
Format: Article in Journal/Newspaper
Language:English
Published: Waterbird Society
Subjects:
Online Access:http://hdl.handle.net/11336/97817
Description
Summary:A total of 124 pellets (regurgitated casts) produced by the Neotropic Cormorant (Phalacrocorax olivaceus) were collected monthly between January 2004 and November 2005 from a roosting site at Rosario Lake Chubut, Patagonia, Argentina. Analyses of the samples showed that fish were the most frequent and important prey by number, followed by crustaceans and molluscs. The three fish species inhabiting Rosario Lake were represented in the diet which suggests that this bird is a generalist feeder. However, cormorants positively selected for Patagonian Silverside and Rainbow Trout, which might be related to their foraging strategy and/or to the conspicuousness of potential prey. The estimated annual fish intake by cormorants at Rosario Lake ranged between 2.3-3.7 tons of fish or 16,000-26,000 individuals. The impact produced by the Neotropic Cormorant on recreational fish resources and local fish farms appears negligible. Fil: Casaux, Ricardo Jorge. Ministerio de Relaciones Exteriores, Comercio Interno y Culto. Dirección Nacional del Antártico. Instituto Antártico Argentino; Argentina. Universidad Nacional de la Patagonia "San Juan Bosco"; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina Fil: Di Prinzio, Cecilia Yanina. Universidad Nacional de la Patagonia "San Juan Bosco"; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina Fil: Bertolin, María Lila. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina Fil: Tartara, Maria Alejandra. Universidad Nacional de la Patagonia "San Juan Bosco"; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina