Short-term mercury exposure affecting the development and antioxidant biomarkers of Japanese flounder embryos and larvae

This study investigated the acute and sub-lethal toxicities of waterborne mercuric chloride to Japanese flounder (Paralichthys olivaceus) embryos and larvae. Acute toxicity tests indicated that the 48-h LC50 values of mercury to the embryos and larvae were 48.1 (32.8–63.6) and 99.4 (72.9–147.0) μg L−1, respectively. Mercury could cause low hatching success, delayed hatching process, reduced growth at concentrations ≥20 μg L−1, and induce reduced survival and higher morphological malformations at concentrations ≥40 μg L−1 in the embryos and larvae. In sub-lethal toxicity test, superoxide dismutase (SOD) and catalase (CAT) activities, reduced glutathione (GSH) and malondialdehyde (MDA) contents of the larvae were significantly increased, while glutathione-S-transferase (GST) was decreased by 10 days of 0–10 μg Hg2+ L−1 exposure. These findings suggested that the hatching, survival, growth and antioxidant biomarkers of the flounder were sensitive to the highest mercury concentrations and could thereby serve as potential biomarkers for evaluating mercury contamination in the aquatic environment.