Oestrogens have no hormonal effect on the development and reproduction of the harpacticoid copepod Nitocra spinipes

In recent years, reports have described endocrine-disruptive effects of environmental oestrogens in fish, but little is known about similar effects in crustaceans. The objective of the present study was therefore to examine whether the oestrogens 17-beta -oestradiol, 17-alpha -ethynylestradiol and diethylstilbestrol (DES), could affect mortality, larval development rate, fecundity and sex ratio in the sexually reproducing harpacticoid copepod Nitocra spinipes. Newly released naaplii (< 24-h old) were exposed to 1/1000, 1/100 and 1/10 (nominal concentrations) of each oestrogen's 96 h-LC50 value for less than or equal to 18 days at 22 +/- 1 degreesC. The percentage of gravid females and the number of developed copepodites were both reduced at 0.03 mg l(-1) DES, although the latter response was not significant. None of the other two oestrogens induced any measurable effects. Since the only observed significant response appeared at a DES concentration no more than 10 times below the 96 h-LC50 value, there is no evidence of endocrine-disruptive activity in N. spinipes exposed to oestrogens. (C) 2001 Elsevier Science Ltd. All rights reserved.