Abstract

The grey snapper (Lutjanus griseus and lane snapper (Lutjanus synagris) are species commercially important in the mexican fisheries. The fishing volume of these two species is only superable by the grouper (Epinephelus morio). Nevertheless, there is little knowledge of the nourishment of adults and even less of juveniles. The stomach content of juveniles from the two species collected thruoghout two years were analyzed. The five main groups found in both species were Amphipoda, Mysidacea, Brachiura, Penaeidae and prey-fish. There was an ontogenic shift between fishes < 90 mm and >90 mm in both species. L. griseus < 90 mm feed on small preys and > 90 mm change to larger preys. L. synagris < 90 mm consumed the same proportion of small and large preys and > 90 mm quit consuming small preys and base their nourishment on large preys. The trophic intraspecific interaction was significant between near size classes and gradually diminished when the difference of size class raised. The trophic interspecific interaction was very high, however feeding schedules in each species might have concealed the real values of interaction between them. There was small alimentary variation throughout the two years in both species, perhaps due to food availability of the dynamic tropical ecosystems.

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