Enhancement of Chinese shrimp in northern Yellow Sea, China
Ye Changchen Li Peijun Liu Haiying Wang Wenbo Dong Jing Chen Tan ※ (Marine Fisheries Reaearch Institute of Liaoning, Dalian 116023) (※ Dalian Worker's University)
Based on the abundance index of young Chinese shrimp pre- and post-releasing in northern Yellow Sea during 1985～1992,the percentage of released amount in mixed stock (wild and released) was estimated as 92% in average, and the mean recapture rate was 9.2%. The relationship between the postreleased abundance index (Y) and released amount (X) can be presented as Y=24.01X-1.00 3X 2,R=0 898. The significance of correlation is significant when examined by using of F test. The best effect of enhancement can be obtained with a medium released amount.The optimum released amount corresponding with the maximum yield was 1.6 billion ins, and that with the maximum abundance index was about 1.2 billion ins.The death character of the released shrimp was described and the mortalities under different conditions were estimated. Up to opening date(August 15) the survival amount with Cohort Analysis was about 10.5% of the released. The fishing mortality was 0.82 and the natural mortality was 0.11 during the fishing season. The rest 0.07 of the released amount migrated to the wintering ground out of northern Yellow Sea.