Diet of common dolphinfish (Coryphaena hippurus) in the Pacific coast of Ecuador

Abstract

The diet and the feeding habits of the common dolphinfish (Coryphaena hippurus) in the Pacific coast of Ecuador was assessed by examining 320 stomachs of individuals ranging from 51 to 149 cm in total length. Fish was the predominant prey group in the diet (Alimentary Index, %AI = 95.39) followed by cephalopods (%AI = 4.13) and crustaceans (%AI = 0.48). Among the 17 prey items that make up the dolphinfish diet, the Exocoetidae family was the most important prey (%AI = 57.13), Dosidicus gigas being the most abundant invertebrate species (%AI = 7.65). Feeding patterns were evaluated using the graphing method of Amundsen, which suggested that this species shows a varying degree of specialization on different prey taxa. Thus, while some species were unimportant and rare (Hippocampus hippocampus, Lagocephalus lagocephalus, Gobiidae and Argonauta sp.), several dolphinfishes showed a high degree of specialization on Scombridae, Pleuroncodes planipes, Portunus xantusii and Opisthonema libertate. Size-related and temporal shifts in dietary composition were investigated by PERMANOVA analysis, which showed wide variations among size classes and periods of capture. The results of this study indicate that the common dolphinfish is an opportunistic feeder, which is capable of consuming a wide variety of schooling epipelagic organisms.