| Adult mummichog (Fundulus heteroclitus) were exposed to 0, 0.1, 1, 10 or 100ng/L 17alpha-ethynylestradiol (EE2) for 21 and 28 days in a reproductive bioassay assessing endocrine and reproductive endpoints. The exposure protocol continued for 63 weeks with their offspring in an early life-stage bioassay assessing embryonic survival and hatching, and a growout protocol assessing growth and reproductive potential. Minimal disruption to adult reproductive endocrine status, offspring development and reproductive potential occurred in fish exposed at environmentally-relevant concentrations of EE2(≤10ng/L). In fish exposed to the highest concentration of EE2 tested (100ng/L), vitellogenin was induced in adult male fish and juvenile females; gonadosomatic index (GSI), spawning, fertilization, circulating steroid levels and gonadal steroid production were affected in adult fish; and hatch success and male GSI decreased, and the sex ratio was skewed to >80% female in the offspring. These effects have the potential to affect long-term population sustainability. This work furthers our ability to extrapolate between short-term endocrine response and population-level responses in endocrine disruption studies. |
