Effects of 17.BETA.-estradiol on the Reproduction of Freshwater Shrimp, Paratya compressa improvisa

In this study, we investigated the effects of an endocrine disruptor, 17β-estradiol, on the reproduction of freshwater shrimp, Paratya compressa improvisa (Natantia, Decapoda, Crustacea). Female shrimps with fertilized eggs were exposed to 0.1, 1.0, and 10μg·l-1 17β-estradiol. Larval mortality after 14 days of hatching for these female shrimps significantly increased from 2.0% in the control group to 66-80% in the exposed groups. On the other hand, when larvae of this species, obtained within 24 h after hatching, were exposed to 0.1, 1.0, and 10μg·l-1 17β-estradiol, larval mortality after 14 days of hatching slightly increased from 2.0% in the control group to 3.9-9.2% in the exposed groups. The sex ratio (female/male) of adults exposed to 17β-estradiol changed markedly from 1.1 in the control group to 0.5 in the exposed groups at 1.0 and 10μg·l-1. Female shrimps with fertilized eggs were observed after 150 days of hatching in the control group and the exposed groups at 0.1 and 1.0μg·l-1. The larval mortality of the next generation after 14 days of hatching gradually increased from 0.8-3.4% in the control group to 8.1-16% in the exposed group at 0.1μg·l-1 and 64-84% in the exposed group at 1.0μg·l-1. These results suggest that this compound affects the reproduction of this species.