1. East China Sea Fisheries Research Institute, Chinese Academy of Fishery Sciences, Shanghai 200090, P. R. China
2. Beijing Research Center for Agricultural Standards and Testing, No. 9 Middle Road of Shuguanghuayuan, Haidian District, Beijing 100097, P. R. China
3. Physical Chemistry Laboratory, UFR SSMT, Université Felix Houphouet Boigny, 22 BP 582, Abidjan 22, Cote d’Ivoire