POPULATION DYNAMICS AND SECONDARY PRODUCTION OF CORBICULA FLUMINEA (MÜLLER, 1774) IN A TYPICAL AQUACULTURAL LAKE (DATONG) OF THE CENTRAL YANGTZE RIVER BASIN, CHINA

Samples of Corbicula fluminea (Müller, 1774) were collected monthly from March 2011 to February 2012 in the Datong Lake to study its population dynamics and secondary production in its native environment. A total of 4,108C. fluminea were collected and measured, with shell length (SL) ranging from 3.41 to 29.58 mm, and wet weight (WW) ranged from 0.005 to 10.03 g. The calculated SL-WW equation was log WW = –3.52+3.08 log SL (R²=0.97), which showed that the growth curve of C. fluminea followed a positive allometric pattern. The recruitment patterns peaked in one from March to April and the other one during the months of August to October. The mean annual abundance and biomass ( \bar B ) were (274±95) ind./m² and (20.1±5.7) g AFDW/m² (Ash Free Dry Weight, AFDW), respectively. The annual secondary production (P) was estimated to be 23.90 g AFDW/m²·year, resulting in a P/ \bar B ratio of 1.20/year and a turnover time of 298 days. The asymptotic maximum length (L_∞), curvature parameter (K) and seasonal oscillation in growth rate (C) derived from the von Bertalanffy Seasonal Growth Formula (VBSGF) were 31.91 mm, 0.45/year, and 0.84, respectively. The slowest growth period was in January, and the potential lifespan (t_max) was estimated to be 4.44 years. The total mortality (Z), natural mortality (M) and fishing mortality rates (F) estimated were 1.68/year, 0.89/year and 0.79/year, respectively. Its exploitation rate (E=0.47) indicated a slightly high exploited stock that needs some management intervention to maintain the sustainability of this fishery resource.