1. Institute of Marine Affairs; National Sun Yat-sen University; 70 Lien-hai Road Kaohsiung 804 Taiwan
2. Department of Applied Mathematics; National Sun Yat-sen University; 70 Lien-hai Road Kaohsiung 804 Taiwan
3. Department of Environmental Biology and Fisheries Sciences; National Taiwan Ocean University; 2 Pei-Ning Road Keelung 202 Taiwan
4. Institute of Oceanography; National Taiwan University; Number 1, Section 4 Roosevelt Road Taipei 106 Taiwan
5. National Marine Fisheries Service; Pacific Islands Fisheries Science Center; Honolulu Hawaii 96816 USA