Seasonal Food Composition and Prey-Length Relationship of Pipefish Nerophis ophidion (Linnaeus, 1758) Inhabiting the Aegean Sea

Abstract

        This study examined the gut content of 43 Nerophis ophidion individuals obtained from Izmir Bay, Eastern Aegean Sea. A four season sampling process provided 7 groups of prey: Ostracoda, Amphipoda, Gastropoda, Cirripedia, Decapod crustacea, bentic Cinideria and Copepoda (Calanoid, Harpacticoid, Cyclopoid-Sapphirina sp., E. acutifrons and Monstrilloid) Harpacticoid copepod, Cyclopoid copepod Cypris larvae and Ostracoda. Only 4 stomachs were empty. Gastropoda (9.47%), Amphipoda (37.22%) and Harpacticoid copepod (1.77%) are considered as dominant prey in the food composition of N.ophidion. On the other hand, Harpacticoid and Cyclopoid copepods are found in almost all sampling periods, and thus they are considered as major prey. Amphipoda was the most predominant prey in both spring (24.39%) and summer (12.82%), and Gastropoda (6.32%) in autumn. The presence of Harpacticoid copepods consumed by almost all lengths of fish indicates that their intake by pipefish derives from bentic vegetation rather than the water column. The ability to consume larger prey may be correlated with fish size. In our study, while larger Nerophis ophidion had an intake of relatively larger prey, they continued to catch smaller prey items as well. This result may imply that the bigger the fish in size, the more prey groups they could catch.