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-β-oestradiol, 17-α-ethynylestradiol and diethylstilbestrol (DES), could affect mortality, larval development rate, fecundity and sex ratio in the sexually reproducing harpacticoid copepod Nitocra spinipes. Newly released nauplii (<24-h old) were exposed to 1/1000, 1/100 and 1/10 (nominal concentrations) of each oestrogenʹs 96 h-LC50 value for ≤18 days at 22±1°C. 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.