STOMACH CONTENTS OF FALSE KILLER WHALES (PSEUDORCA CRASSIDENS) STRANDED ON THE COASTS OF THE STRAIT OF MAGELLAN, TIERRA DEL FUEGO

Authors

  • Mariano Koen Alonso,

    1. Centro Nacional Patagónico (CENPAT), Boulevard Brown 3600, (9120) Puerto Madryn, Chubut, Argentina Universidad Nacional de la Patagonia, Boulevard Brown 3700, (9120) Puerto Madryn, Chubut, Argentina E-mail: koen@cenpat.edu.ar
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  • Susana N. Pedraza,

    1. Centro Nacional Patagónico (CENPAT), Boulevard Brown 3600, (9120) Puerto Madryn, Chubut, Argentina Universidad Nacional de la Patagonia, Boulevard Brown 3700, (9120) Puerto Madryn, Chubut, Argentina E-mail: koen@cenpat.edu.ar
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  • Adrian C. M. Schiavini,

    1. Centro Austral de Investigaciones Cientificas (CADIC), Casilla de Correo 94, (9410) Ushuaia, Tierra del Fuego, Argentina
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  • R. NATALIE P. Goodall,

    1. Centro Austral de Investigaciones Cientificas (CADIC), Casilla de Correo 94, (9410) Ushuaia, Tierra del Fuego, Argentina
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  • Enrique A. Crespo

    1. Centro Nacional Patagónico (CENPAT), Boulevard Brown 3600, (9120) Puerto Madryn, Chubut, Argentina Universidad Nacional de la Patagonia. Boulevard Brown 3700, (9120) Puerto Madryn, Chubut, Argentina
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Abstract

We examined the stomachs of 25 false killer whales collected from a mass stranding of 181 animals along both coasts of the Strait of Magellan, Chile, in March 1989. The 21 stomachs (nine males and 12 females), with food remains contained 11 prey species (nine cephalopods and two fishes) with a total of 442 individuals. Except for one case, food remains were meager, indicating that the animals had not eaten for some time or through stress had vomited on the beach. Eleven of the 21 animals had mud (often with squid beaks) in the esophagus and first stomach. The prey were identified employing squid beaks, fish otoliths and bones, and their wet weights were estimated using regressions between hard parts and known weights of species. The most important prey were the oceanic and neritic-oceanic squids, Martialia byadesi and Illex argentinus, followed by the neritic fish, Macruronus magellanicus. Of less importance were the oceanic squid, Todaroes fillipovae, the oceanic and epipelagic octopus, Ocytboe sp., and the oceanic squid, Moroteuthis ingens. The rest of the prey were poorly represented and included four oceanic squids and one neritic fish. The prey species of these animals were subantarctic, with two antarctic species, abundant over the Patagonian shelf and adjacent oceanic waters around Tierra del Fuego.

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