Cadmium toxicity to embryonic-larval development and survival in red sea bream Pagrus major

Abstract

At 18 degrees C and 33 psu, 24 and 48 h LC(50) values of cadmium (Cd) for red sea bream Pagrus major embryos were 9.8 and 6.6 mgl(-1), respectively, while 24, 48, 72, and 96 h LC(50) values for larvae were 18.9, 16.2, 8.0, and 5.6 mgl(-1), respectively, indicating that embryos were more sensitive to Cd toxicity than larvae. Cd concentrations at > or =0.8 mgl(-1) led to low hatchability (0-90% in > or =0.8 mgl(-1) solutions vs. 97-100% in lower ones), delay in time to hatch, high mortality (38-100% vs. 1-10%), morphological abnormality (42-100% vs. 1-10%), reduced length (3.55-3.60 vs. 3.71-3.72 mm) in the embryos and larvae. They were Cd concentration dependent and potential biological significant endpoints for assessing the risk of Cd to aquatic organisms. Heart beat and yolk absorption of the larvae were significantly inhibited at some high concentrations but they were not as sensitive as other endpoints to Cd exposure.