Diet of three shark species in the Ecuadorian Pacific, <italic>Carcharhinus falciformis, Carcharhinus limbatus</italic> and <italic>Nasolamia velox</italic>.

We analysed the stomach contents of 69 silky sharks <italic>Carcharhinus falciformis</italic>, 44 blacktip sharks <italic>Carcharhinus limbatus</italic> and 24 whitenose sharks <italic>Nasolamia velox</italic> caught in the Ecuadorian Pacific from August 2003 to December 2004. Prey included bony fishes, elasmobranchs, molluscs, crustaceans and turtles, with bony fishes being the most important to the diets of all three sharks, suggesting they are piscivorous predators. Based on the index of relative importance, the <italic>C. falciformis</italic> diet includes <italic>Thunnus albacares, Thunnus</italic> sp. and <italic>Auxis thazard</italic>, as well as some squid, fish and turtles. Similarly, the <italic>C. limbatus</italic> diet was dominated by <italic>T. albacares, Exocoetus monocirrhus, A. thazard, Katsuwonus pelamis</italic>, members of the Ophichthidae family and other elasmobranchs. Meanwhile, <italic>N. velox</italic> consumed mainly <italic>Dosidicus gigas, Larimus argenteus, Cynoscion</italic> sp. and <italic>Lophiodes spilurus</italic>. There is little competition for food between these tertiary carnivores: <italic>C. limbatus</italic> prefers prey from coastal-oceanic habitats; <italic>C. falciformis</italic> consumes mostly oceanic prey and <italic>N. velox</italic> focuses on prey from coastal habitats. The lack of information on the biology of sharks in Ecuador hinders the development of appropriate management and conservation plans to protect shark resources. This study increases our knowledge and understanding of sharks in Ecuador, thus contributing to their conservation. [ABSTRACT FROM AUTHOR]