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Abstract: A six-day static-renewal toxicity test was performed to determine the influences of cadmium on the development of embryos of soldatov''s catfish (Silurus soldatovi). The median lethal concentration (LC50) value and median effective concentration (EC50, i.e., the total adverse effects, including developmental defects and mortality) were calculated to be 2740 and 133μg/L, respectively, when cadmium was prepared in dilution water. The LC50 decreased to 266μg/L in a subsequent test one month later, thereby suggesting that the sensitivity of this fish to cadmium in the early life stage 1 [1] The early life stage terminology used here is defined by . Embryo, stage before hatching; pro-larva, stage between hatching and yolk sac resorption; larva, stage between yolk-stage resorption and juvenile morphology. was largely influenced by the quality of fertilized eggs, which is known to be dependent on the season. The mortality and total adverse effects showed a concentration-dependent relationship at dosages greater than 1000 or 10μg/L (p<0.05), respectively, at pro-larva stage (i.e., 144hpf) with dilution water. To compare the toxic effects of cadmium under field and experimental conditions, filtered river water was adopted as a solvent simultaneously compared with dilution water. No significant differences were observed in mortality rate, hatching rate and adverse effect prevalence between the two solvents. In comparison to previously published toxicity data for other fish, the pro-larva of soldatov''s catfish were less sensitive than established test fish in the early life stage. Therefore, the environmental risks would be overestimated when considering only existing toxicity data for other test fish. [Copyright &y& Elsevier]