태안 주변해역에 출현하는 홍어(Okamejei kenojei)의 식성

Abstract

Feeding habits of Okamejei kenojei were studied based on 500 specimens collected in the coastal waters off Taean, Korea from April 2008 to March 2009. The size of Okamejei kenojei ranged from 8.2 to 49 cm in total length (TL). Okamejei kenojei was a carnivore which consumed mainly shrimps, fishes, and crabs. Its diet also included small quantities of amphipods, mysids, mantis shrimps, cephalopods, euphausiids, copepods, cumaceans, isopods, and polychaetes. It showed ontogenetic changes in feeding habits. Although shrimps were eaten predominantly for all size groups, the proportion of shrimps to total prey items decreased with increasing fish size. Instead, the proportions of fish and crabs increased gradually with increasing fish size. The size of prey organisms including shrimps were differed with increasing of fish size. The relative proportion of the major prey items changed with season; Okamejei kenojei fed relatively various prey organisms in spring and autumn, whereas the consumption of shrimps was higher in summer and winter. The dietary breadth index increased, but stomach content index decreased with increasing of fish size.