Diet of the bull shark, Carcharhinus leucas, and the tiger shark, Galeocerdo cuvier, in the eastern Pacific Ocean

Authors : Colombo ESTUPIÑÁNMONTAÑO, José F ESTUPIÑÁNORTIZ, Luis G CEDEÑOFIGUEROA, Felipe Galvan MAGAÑA, Carlos J POLOSILVA

Pages : 1111-1117

View : 10 | Download : 4

Publication Date : 0000-00-00

Article Type : Research Paper

Abstract :This study presents information on the diet of two shark species, Carcharhinus leucas and Galeocerdo cuvier, that inhabit the southeastern Pacific Ocean. The stomachs were collected from October 2003 to July 2005 in Ecuador. Stomachs of 41 C. leucas and six G. cuvier were analyzed. According to the index of relative importance insert ignore into journalissuearticles values(%IRI);, the most important prey for C. leucas were fishes: family Ophichthidae insert ignore into journalissuearticles values(13.41%);, Tylosurus pacificus insert ignore into journalissuearticles values(9.79%);, Katsuwonus pelamis insert ignore into journalissuearticles values(4.54%);, and fish remains insert ignore into journalissuearticles values(44.81%);. G. cuvier, for its part, consumed squids: Ancistrocheirus lesueuri insert ignore into journalissuearticles values(45.14%);, Pholidoteuthis boschmaii insert ignore into journalissuearticles values(7.81%);, and Octopoteuthis spp. insert ignore into journalissuearticles values(5.17%);, as well as turtles: Caretta caretta insert ignore into journalissuearticles values(9.7%);, Lepidochelys cf. kempii insert ignore into journalissuearticles values(5%);, and turtle remains insert ignore into journalissuearticles values(16.5%);. The results show that C. leucas insert ignore into journalissuearticles values(trophic level, ITR; 4.32 $\pm$ 0.13); and G. cuvier insert ignore into journalissuearticles values(ITR; 4.26 $\pm$ 0.09); are tertiary consumers, occupying high positions in the food chain, but also are generalist predators that feed on a variety of prey. The high frequency of sea turtles in the stomachs of G. cuvier insert ignore into journalissuearticles values(>300 cm); suggests that this shark species is an important predator of turtles, which are commonly found along the southeastern Pacific coasts.
Keywords : Top predator, feeding habits, trophic level, Ecuador, stomach contents