Toxicity of Mercury to Growth and Survival of Seabass Larvae, Lates calcarifer and the Modifying Effects of Salinity

Abstract

ABSTRACT: Short-term chronic toxicity tests were conducted to investigate the adverse effects of mercury (Hg) on growth (measured as dry weight) and survival of seabass larvae, Lates calcarifer, and the modifying effects of salinity. Seven-day static-renewal tests were conducted at four salinities: 2, 10, 20 and 30 psu. The experiments were repeated three times for each salinity. Results indicated that seabass larvae were very sensitive to low concentrations of Hg. Based on the actual measured Hg concentrations, the mean NOEC, LOEC and LC 50 values for survival were 30.8, 52.5 and 46.2 µg L -1 , respectively, while the mean NOEC, LOEC, IC 25 and IC 50 values for growth were 5.2, 12.6, 8.5 and 19.2 µg L -1 , respectively. Salinity did not have any significant effects on the toxicity of Hg on survival and growth of seabass larvae. One possible explanation is that Hg preferentially forms very strong complexes with sulfhydryl groups (-SH) in proteins rather than with chloride