Effects of Wood-Related Sterols on the Offspring of the Viviparous Blenny, Zoarces viviparus L.

The parent generation of the viviparous blenny, Zoarces viviparus L., were exposed to phytosterols (a) from oogenesis to parturition and (b) from breeding to parturition. The experiments were performed under laboratory conditions in a test unit supplied with continuous renewal of brackish water. After parturition the offspring were further reared either in clean or in phytosterol-contaminated brackish water. The objective was to study the significance of preexposure of the parent on the effects of phytosterols on the offspring in comparison with effects occurring directly on previously unexposed offspring. The phytosterol concentrations used were (a) 0, 10, 20, and 30 μ g/L and (b) 0, 10, and 20 μ g/L. Offspring exposed in (a) was further reared in clean water and in (b) offspring from parents exposed to 10 μ g/L was either exposed further in the same concentration or left in clean water. Offspring from parents exposed to 20 μ g/L was further exposed in the same concentration. Finally one group from unexposed parents was exposed to 10 μ g/L after birth. The offspring was studied for 6 months after birth. The results showed that blenny offspring are affected by phytosterols at exposure through the parental generation. The results imply that phyto- sterols affect embryological development of the larvae before hatching as well as the levels of circulating hormones of the parent fish. The larvae contained higher levels of phytosterols as did controls and the bile of exposed female fish contained lower levels of phytosterols implying a link between the higher levels in larvae and lower excretion of the females. The growth of the larvae at 10 μg/L was stimulated regardless of whether the larvae were further exposed, indicating that newborn larvae carried within the female are sensitive to exposure to phytosterols.