Comparison of the Feeding Characteristics of Chub Mackerel Scomber japonicus in Jeju Island and the Yellow Sea of Korea

The feeding characteristics of the chub mackerel, Scomber japonicus from Jeju Island waters and the Yellow Sea were compared by analyzing the stomach contents. Large and small purse seines were used to collect 1437 individuals from Jeju Island waters and 1066 individuals from the Yellow Sea. The fork length of S. japonicus ranged from 21.0 to 43.6 cm for individuals from Jeju Island waters and 19.6 to 41.5 cm for those from the Yellow Sea. Based on the index of relative importance and variation in stomach contents according to fish size, S. japonicus was identified as a piscivore and a spatiotemporally opportunistic feeder. The proportion of fish in the diet increased as the body sizes of S. japonicus from both Jeju Island waters and the Yellow Sea increased, whereas the proportion of copepods, amphipods, and euphausiids gradually decreased. Differences in stomach content compositions were observed due to interactions between size and location. Thus, the feeding characteristics of S. japonicus are affected by the abundance and composition of prey in its habitat.