Diets of abundant fishes from beach seine catches in seagrass beds of a tropical bay (Gazi Bay, Kenya)

The composition of the diet of 14 fish species that were common in beach se ine catches over the seagrass beds of Gazi Bay (Kenya) was investigated. Th ree trophic guilds could be distinguished based on dietary diversity and on the numerical and gravimetrical composition of the diet. Herklotsichthys g uadrimaculatus, Stolephorus indicus and Atherinomorus duodecimalis were pla nktivores. Their stomach fulness index was low and the diet was not diverse . The main food items were harpacticoid and calanoid copepods and brachyura n zoea and megalopae. Apogon thermalis, Fowleria aurita, Paramonacanthus ba rnardi, Mulloides flavolineatus, Lutjanus fulviflamma, L. argentimaculatus and Gerres acinaces were benthivores, mainly feeding on small epi- and hype rbenthic prey. Their diet was very diverse and it was dominated by Amphipod a (Gammaridea), Tanaidacea and Mysidacea. Their fulness indices were low, b ut a little bit higher than those observed for the planktivores. A third gr oup were the << piscivores >>: Bothus myriaster, Fistularia commersonii, Sp hyraena barracuda and Plotosus lineatus. The dominant items in the food spe ctrum of these species were postlarval fishes and large nektonic invertebra tes (gammaridean amphipods, mysids, shrimp and crabs). Their diet was not d iverse and the fulness index was much higher than that of the other species examined. All other species caught were further classified according to th e following feeding guilds : herbivores, planktivores, benthivores (epi- an d hyperbenthivores) and piscivores. The ichthyofauna of Gazi Bay was clearl y dominated by benthivores.