Diet composition of carnivorous fishes from coral reef lagoons of New Caledonia

A total of 212 carnivorous coastal fish species from New Caledonia, represented by 7335 individuals, were analysed for their diet. Fifty two prey items were identified and later grouped into broader taxonomic categories refered as prey types. For each fish species 6 biological traits were defined: maximum adult size, major biotope, schooling behaviour, home range, nycthemeral behaviour, degree of crypticity. A general linear model was fit to the diet data taking into account these traits, and depth of capture and fish family. This model was applied to the average number of prey types/stomach and to the volume of 5 prey types: nekton, crustaceans. molluscs, echinoderms, worms. A second analysis was performed on the effect of observed size on diet composition, taking into account these traits and taxonomy. This analysis was restricted to species with at least five individuals, representing 113 species from 33 families. More detailed information is given for the three major families, Serranidae, Lutjanidae and Lethrinidae and intra-family variations are illustrated for Lethrinidae. All the factors tested had significant effects on diet. fish size and taxonomy being the two major factors. The five prey types analysed in detail displayed marked differences according to the factors studied. In particular nekton increased in importance with fish size, whereas crustaceans decreased and molluscs presented a dome shaped relationship. Nekton and crustaceans made the bulk of the diet of most species, with molluscs being at times important. Echinoderms and worms were never a major food item and were eaten only by a restricted range of species.