Effects of 17beta-estradiol on survival, growth, sexual development and molting cycles of the marine crustacean mysid shrimp, Americamysis bahia.

A 14-day partial life-cycle test was performed to assess the effects of 17beta-estradiol (E2) on the survival, growth, sexual development and molting cycles of a marine crustacean mysid shrimp (Americamysis bahia). Seven-day-old mysids were exposed to the nominal E2 concentrations of 31.3, 62.5, 125, 250 and 500 microg/l for 14 days. The total length and the body weight of mysids significantly decreased relative to the controls when exposed to 62.5, 250 and 500 microg/l E2 for 14 days. Moreover, the carapace length significantly decreased in the 500 microg/l E2 treatment groups. No significant differences were observed in sex ratio with the appearance of secondary sex characteristics in the all treatment groups including the control and solvent control groups. However, the percentage of females with eggs in the oviduct or brood sac decreased significantly in mysids treated with E2 at 62.5, 125, 250 and 500 microg/l. The cumulative total number of molting cycles when exposed to E2 for 14 days significantly decreased in the treatment groups at 500 microg/l relative to the controls. These results suggest that concentrations of E2 over 62.5 microg/l may cause growth suppression in mysid shrimp, and that the disruption of molting cycles may result in alterations in growth due to a sublethal response to toxicant exposure.