東京湾湾口部館山湾におけるウツボの食性とその季節変動

抄録

The diet and feeding habits of the Kidako moray eel Gymnothorax kidako in Tateyama Bay, Chiba Prefecture, Japan were investigated. Of 348 specimens collected in traps, 214 had empty stomachs. Prey of the remaining specimens included teleosts, cephalopods, crustaceans, and polychaetes, evidence of the carnivorous role of the former, feeding primarily on fishes. Notably, predation of tetrodotoxin-possessing species, such as the grass puffer, implied a potentially significant impact of G. kidako on reef ecosystems. Additionally, seasonal variations were apparent in the gastric emptying rate of G. kidako, suggesting differing feeding activities during the breeding and non-breeding seasons. To precisely evaluate the feeding habits of G. kidako in Tateyama Bay, future research should carefully consider sampling methods, so as to ensure a sufficiently large sample size for a comprehensive study.