Induction of Intersex and Masculinization of the Equilateral Venus,Gomphina veneriformis(Bivalvia: Veneridae) by Zinc

Abstract This study aims to find out the effect of heavy metals, as is the case of EDCs (endocrine disrupting chemicals), on reproductive endocrine disruption of aquatic animals. In the present experiment zinc, which is a heavy metal well known for its androgenous activity, was used. The experimental period was 24 weeks, starting in November during the inactive stage of the clam's reproductive cycle. The experimental groups were composed of one control condition and three zinc exposure conditions (0.64, 1.07, and 1.79 mg/L). The sex ratio (F:M) was 1:1.06 in the control group and 1:1.70 in all the exposed group, illustrating the tendency for higher proportion of males with increases in zinc concentration. Gonad maturity was higher in 1.07, and 1.79 mg/L groups compared to the control group, with higher maturity observed in males than females. Intersex individuals made up 24.7% of the exposed group, while females exhibited a higher ratio than the males with increasing zinc concentration. The results of this study indicate that zinc functions as an androgenic effector on the reproduction of Gomphina veneriformis. Key words: Gomphina veneriformis sex ratiogonadal activityintersexandrogenic effectorzinc Notes To whom correspondence should be addressed. Tel: +82–61 ‐659–3172; Fax: +82–61 ‐659–3172 E‐mail: ljs@chonnam.ac.kr