1. Department of Aquaculture, Pukyong National University, 599-1, Daeyeon Dong, Nam Gu, Pusan 608-737, South Korea
2. Department of Oceanography, Pukyong National University, 599-1, Daeyeon Dong, Nam Gu, Pusan 608-737, South Korea
3. Faculty of Fisheries, Nagasaki University, 1-14 Bunkyo-machi, Nagasaki 852-8521, Japan