Diet Composition and Feeding Habits of Fish Larvae of Five Species in the Burullus Lake, Egypt

Abstract

Feeding habits of fish larvae were analysed in a comparative study of five species (Oreochromis niloticus, O. aureus, Tilapia zilli, Mugil cephalus and Liza ramada) from the Burullus Lake. We investigated the potential influence of larvae size on their feeding and looked for common patterns in larval prey preference. Gut contents of a total of 1068 larvae were examined. The feeding habits of the examined larvae shared some characteristics. As larvae of the five species grew, the preferred prey size and the number and diversity of prey in the gut increased. On the other hand, larval feeding also differed in several aspects, especially differences in the composition of preferred prey items. For Cichlidae larvae, the dominant prey was the rotifer Brachionus plicatilis followed by copepodite stages. For M. cephalus larvae, the copepods Paracalanus sp and Acartia sp were the most important diets, while for L. ramada, decapod larvae were the most important. The Mugilidae larvae consumed significantly larger prey than the cichlid larvae, which could be related to their morphology, especially the mouth size. Ivlev’s selectivity index calculated for larvae showed positive selection for particular prey. In all the species, copepods were the most selected, particularly for Mugillidae larvae, but for Cichlidae larvae, the rotifer Brachionus competed with copepods as a selected prey. This dietary study of fish larvae of these important species is essential for the development of fisheries and can be implemented in further related studies of other areas.