Reproductive success and behavior of Japanese medaka (Oryzias latipes) exposed to 4‐tert‐octylphenol

Abstract

Japanese medaka (Oryzias latipes), a small freshwater fish used extensively to investigate sexual differentiation and development, were exposed to octylphenol (OP), a known estrogen agonist, to assess its impact on reproductive success. Male and female medaka were exposed to nominal concentrations of 10, 25, 50, and 100 μg/L OP from 1 d posthatch to 6 months posthatch. In reproduction trials involving exposed males and unexposed females, the males exposed to nominal concentrations of 25 and 50 μg/L showed a reduction in some courtship activity and overall reproductive success. Eggs produced by matings of exposed males and females demonstrated various developmental problems, including circulatory system difficulties, incomplete eye development (i.e., anisophthalmia), and failure to inflate swim bladders upon hatch. One male fish with an intersex gonad was able to fertilize the eggs of an unexposed female. This study is one of the first to show the possible behavioral and transgenerational effects of an estrogenic compound on the reproductive success and second generation embryo‐larval development of fish.

Octylphenol, Estrogen, Endocrine disruption, Reproductive behavior, Medaka

Issue Section:

ENVIRONMENTAL TOXICOLOGY