Studies on food organisms of pelagic fishes as revealed by the 1979 North Atlantic Eel Expedition

The extent to which pelagic fishes occurring in the Sargasso Sea and adjacent parts of the Atlantic prey on leptocephali (Anguilliformes) was investigated. Most of the fishes examined (c. 95%) were collected using a commercial pelagical trawl. The stomach contents of about 1000 fishes (25 species of 10 families), mostly belonging to the suborders Myctophoidei, Stomiatoidei and the order Anguilliformes, were examined. The remains of invertebrates, mainly crustaceans, molluscs, tunicates, chaetognaths, and siphonophores were found in 28.8 % of the stomachs. Fishes, mostly myctophids or fish remains, were observed in 11.2 % of the stomachs; 18.7 % contained unidentified items and 40.6 % were empty. Leptocephali (Ariosoma spp. and Gnathophis sp.) were found in the alimentary tract of 0.5 % of the fishes examined, exclusively represented by the myctophid, Ceratoscopelus warmingii. This report indicates that the Sargasso Sea population of Anguilla leptocephali, economically the most important eel, is not seriously affected by predation of oceanic fish species considered in this study.