Effects of cadmium chloride on the development of rainbow trout Oncorhynchus mykiss early life stages

The sub-chronic (28-56 days) effects of exposure to low concentrations of cadmium (Cd; 0.05, 0.25, 0.50 and 2.50 mu g 1(-1)) shortly following fertilization on embryos, larvae and juvenile rainbow trout Oncorhynchus mykiss were examined. Premature hatching occurred at lower concentrations (0.05 and 0.25 mu g 1(-1) Cd), however, delayed hatching was seen in the 2.50 mu g 1(-1) Cd group, with > 90% of hatching occurring on the last day of the hatching period. Larval growth was negatively affected by Cd exposure in a concentration-dependent manner. Larvae exposed to 2.50 mu g l(-1) Cd were 13.9 +/- 0.8% shorter in total length (L-T) and weighed 22.4 +/- 3.5% (mean +/- S.E.) less than controls at the end of the exposure period. Plasma sex steroid concentrations (oestradiol in juvenile females and 11-ketotestosterone in juvenile males) were elevated (four- to 10-fold over controls) in exposed fish in both males and females, following 28 days of exposure to 0.05, 0.25 and 0.50 mu g 1(-1) Cd, respectively. These results suggest that environmentally realistic concentrations (in the mu g 1(-1) range) of Cd can affect the development of O. mykiss impacting embryos, larvae and juvenile fish. (C) 2008 The Authors Journal compilation (C) 2008 The Fisheries Society of the British Isles.