Population dynamics and production of <i>Bellamya aeruginosa</i> (Reeve) (Mollusca: Viviparidae ) in Lake Donghu, Wuhan

Abstract

Bellamya aeruginosa (Reeve) is a predominant benthic macroinvertebrate in many shallow lakes along the middle and lower basins of the Yangtze River, and there is little published information on its production in China by far. This paper dealed with the population dynamics and production of B. aeruginosa, a subtropical, shallow, eutrophic lake located near the middle reaches of the Yangtze River. B. aeruginosa was sampled monthly at the eleven stations in Lake Donghu from June 1998 to May 1999. The results showed that the annual average density and biomass were 92.2ind./m2 and 142.83g/m2, respectively, and the density and biomass peaks were observed in June(157ind./m2) and in November(205.78g/m2), respectively. B. aeruginosa population was composed of five year classes, among which the 1998 year class was dominant. The annual production of the animal calculated by instantaneous growth rate method was 91.56g/m2 in wet weight and 5.32g/m2 in dry weight (unshelled), and corresponding annual P/B ratio was 0.64. The production and P/B ratio of B. aeruginosa in the present paper were moderate among the values reported. The study on dynamic of mean daily production of B. aeruginosa showed that the accumulation of production of B. aeruginosa occurred in Spring, Summer and Autumn, and the value of 1998 year class was dominant in the total production.