Factors Affecting Growth and Survival of the Asiatic Clam, Corbicula sp., under Controlled Laboratory Conditions

Abstract

Growth of Asiatic clams (Corbicula sp.) was determined in relation to food supply, water temperature, and clam size as an aid to researchers conducting chronic effects toxicity studies. Mean initial sizes (shell length) of clam groups were small (12 mm), medium (20 mm), and large (28 mm). Water temperatures for the two 84-day test series were 10, 20, and 30°C. Linear models provided good relationships (r2 > 0.90) between clam shell length, total weight, and wet/dry tissue weights. Clam growth was minimal during low phytoplankton densities (∼ 300 cells/mL), and all three size groups lost weight at 20 and 30°C. Mortality of small clams at 30°C was 100% after 71 days. At phytoplankton densities greater than 1000 cells/mL, overall differences in growth with respect to clam size and temperature were detectable at p > 0.01; growth of all clam groups was greatest at 30°C. Small clams exhibited the greatest absolute increase in mean shell length at all test temperatures and their weight gains were similar to those of medium and large clams. Clams in well water that were fed trout chow at 117 mg/mL dry weight had an estimated conversion efficiency of 2.0%. Use of individual marks and multivariate analysis techniques decreased sample size and test duration needed to detect differences in Corbicula growth.