[Estimation of biological parameters and yield per recruitment for Coilia nasustaihuensis in Dianshan Lake, Shanghai, China].

Coilia nasustaihuensis is the most abundant species in Dianshan Lake and plays an important role in the lake ecosystem. From July 2010 to August 2011, a total of 3107 samples of C. nasustaihuensis were collected from Dianshan Lake. Based on length data of these samples, ELEFAN I technique was employed to estimate growth and mortality parameters, and the Beverton-Holt dynamic model was used to evaluate the population dynamics trend for C. nasustaihuensis. Growth of this species was described using avon Bertalanffy model, and the estimated parameters were Linfinity = 35.70 cm, k = 0.54, and t0 = -0.48 a. The turning point for body mass growth curve of the stock was situated at t = 1.37 a. Natural mortality coefficient M was then estimated using Pauly's empirical equation and found to be 0. 872. Length-converted catch curves were used to estimate the total mortality coefficient Z, which was found to be 2.121. Accordingly, the fishing mortality coefficient (F) was equal to 1.249, and the current exploitation rate was 0. 589, suggesting the stock was over-exploited. According to the Beverton-Holt dynamic model, the minimum capture size for C. nasustaihuensis should be 21.42 cm (age 1.22 years).