Optimizing selection and application of reproduction model of small yellow croaker in the East China Sea

Based on time series of abundances collected from demersal trawling surveys in the East China Sea from 1999 to 2008,the author studied the relationship between stock and recruitment of the small yellow croaker in the East China Sea using Ricker,Beverton-Holt and Cushing reproduction models.The best relationship was selected using AIC(Akaike Information Criterion) and BIC(Bayesian Information Criterion) methods,respectively,which had the advantage of testing the significance of the difference between the functions of different model specifications.The environmental factors influencing the relationship between stock and recruitment,were selected using single factor correlation analysis and stepwise regression analysis.The result indicated that the Ricker reproduction model was the best among the three reproduction models.The environmental factors could obviously influence the relationship between stock and recruitment,including the average SST from March to April,and July of the sea area in Lusi fishing ground,the average runoff on May,July and August of Yangzi River and the speed of the summer monsoon in the very year.The optimized model not only increased the precision of predication ability of stock-recruitment model,but also could be used to improve the management objective of the stock.