PRODUCTION OF GASTROPODS IN LAKE BIANDANTANGI.ANNUAL PRODUCTION OF BELLAMYA AERUGINOSA

An investigation on one of the dominant species of gastropods, Bellamya aeruginosa in Lake Biandantang was carried out from April, 1996 to March,1997.The results showed that the population was composed of four year classes, amongwhich the 1996 year class grew most quickly, with instantaneous growth rate of wetweight 4.15 and that of dry weight (unshelled), 3.40. The annual production of theanimal calculated by instantaneous growth rate method was: wet weight 15771.9 mg穖-2穉-1;dry weight (unshelled), 862.4 mg穖-2. a-1. The corresponding annualP/B ratios were almost the same: 0.50, 0.51, respectively. Generaly, relationshipbetween wet weight (Ww, mg穖-2穉-1) and dry weight (Wd, mg穖-2穉-1) ofpreduction of Bellamya aeruginosa is expressed as: Ww = 17.20 Wd.