Effect of zinc pyrithione on reproduction of calanoid copepod

Zinc pyrithione (ZnPT) has been proposed to use as an antifouling compound instead of organotin antifouling biocide in coastal and marine environment. But its impact on marine life especially on smaller zooplankton is so far unknown. The present study was conducted to determine the effect of ZnPT on survival, egg production and egg hatch of a calanoid copepod, Acartia omorii under bath administration. Survival was observed every 24 h for 10 days. Each 10 individuals of adult female were incubated at different concentrations of ZnPT (0.001, 0.01, 0.1, 1, 10 and 100 μg/L) with food (Isochrysis sp. + Tetraselmis sp., ratio 1:1). Egg production was examined through the incubation of single gravid female with above conditions but only in 0.001, 0.01, 0.1 and 1μg/L of ZnPT concentrations. Egg hatching success was determined for each 60 eggs at each concentration of ZnPT, which were obtained from pre-exposed female at the same concentration. Adult survival was affected above 0.1 μg/L concentration of ZnPT and LC₅₀s were obtained in 1, 10 and 100 μg/L concentrations of ZnPT after 72, 48 and 24h, respectively of exposure period. Significant (P < 0.05) decrease in egg production were obtained in 0.1μg/L concentration and above. Egg hatching success was decreased in 1 μg/L concentration. Result suggests that persistent level 0.1 μg/L and above of ZnPT affects the reproduction success of the calanoid copepod, A. omorii.