Combined effect of temperature and food concentration on the filtration and clarification rates and assimilation efficiency of Atrina tuberculosa Sowerby, 1835 (Mollusca: Bivalvia) under laboratory conditions

In Mexico, Atrina tuberculosa and other bivalve mollusks of commercial importance are intensively exploited, resulting in a drastic decline in their natural populations. This makes the ecophysiological studies of our native mollusks very important. The filtration and clarification rates, and the assimilation efficiency of Atrina tuberculosa at three temperatures (17, 22.5 and 28°C) and three microalgae concentrations (20,000, 40,000 and 60,000 cell mL-1) were evaluated under laboratory conditions. The data of each physiological variable were fit to a second-degree polynomial model by the method of square minimums to generate surface response graphs. The temperature and food concentration had a direct and synergic effect on the filtration and clarification rates of the species. The food concentration significantly affected the assimilation efficiency, which was observed to be the highest at the lowest food concentration. The filtration and clarification rates were lower at 17°C as compared to 28°C. No optimal values of assimilation efficiency were observed, which suggests that a wider range of temperatures and food concentration must be evaluated.