Abstract

In order to study the feeding habits of Istiophorids in Venezuela, samples were taken from specimens of the four species of billfish in the area, sail fish (Istiosphorus albicans), blue marlin (Makaira nigricans), spear fish (Tetrapturus pfluegeri) and white marlin (Tetrapturus albidus). The animals were captured on board of long line vessels targeting tunas or swordfish, in the Central and Eastern regions of Venezuela during April/August 1994. The sample consisted of 121 stomachs, from billfish in the size range 115 - 257 cm lower jaw-fork length, and 165 - 257 Kg total weight. Stomach content was analysed according to the method of frequency of occurrence, as well as volumetric and gravimetric analyses. The most frequent food items were pelagic fish and squid. There were also occasionally and accidentally consumed items, like mesopelagic and bathipelagic fish, with very low frequency in the samples. From the 15 families of fishes found, the most frequent were Scombridae, Cupleidae and Carangidae. Most of the identified cephalopods belonged to the species Loligo spp. Other food items found were copepods, crustaceans and gastropods. Additionally, a parasitic fauna was found in the stomachs, integrated by digenetic trematodes, nematodes and cestodes. The vacuity Index from the animals captured in the Central zone was larger (20.3%; 12 empty stomachs) than that of the animals from the eastern region of Venezuela (4.1%; 2 empty stomachs). This fact may be associated with the larger availability of food in the latter region.

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