Tolerance and respiration of a fouling dreissinid bivalve Mytilopsis sallei (Recluz) (Pelecypoda : Dreissinidae) exposed to chromium at different salinities

Chromium tolerance and metabolic rate in Mytilopsis sallei, a fouling bival ve which inhabits Visakhapatnam harbour were studied at different salinitie s such as 10, 15, 25, 32 and 35 parts per thousand. The LC50 values were fo und to increase with increasing salinities indicating a decrease in toxicit y. However, low salinities did not affect the toxicity of chromium. The met abolic rate of the control animals (without toxicant. exposure) showed an i ncreasing trend up to 32 parts per thousand followed by a decrease at 35 pa rts per thousand. In general, different concentrations of chromium (1.9 to 14.4 ppm) inhibited the metabolic rate at all salinities studied.