Reproductive success and behavior of Japanese medaka (Oryzias latipes) exposed to 4-Tert-octylphenol

Japanese medaka (Oryzias latipes) were exposed to octylphenol, a known oestrogen agonist, to assess its effects on reproductive success. Male and female medaka were exposed to nominal concentrations of 10, 25, 50, and 100 micro g/litre octylphenol from 1 day after hatching to 6 months after hatching. In reproduction trials with exposed males and unexposed females, the males exposed to nominal concentrations of 25 and 50 micro g/litre showed a reduction in some courtship activity and overall reproductive success. Embryos produced from matings of exposed males and females displayed various developmental problems, including circulatory system difficulties, incomplete eye development (Anisophthalmia), and failure to inflate swim bladders upon hatching. One male fish with an intersex gonad was able to fertilize the eggs of an unexposed female..