Contaminant Effects on Ovarian Development and Spawning Success in Rock Sole from Puget Sound, Washington

The objective of this study was to determine if exposure to aromatic hydrocarbons (AHs) or polychlorinated biphenyls (PCBs) was associated with altered ovarian development or reduced spawning success in rock sole Pleuronectes bilineatus. This objective was addressed in two separate phases. In the first study, concentrations of AHs and PCB s were measured in individual fish from four sites in Puget Sound, Washington (Eagle Harbor, Sinclair Inlet, Yukon Harbor, and Pilot Point) with different levels of AH and PCB contamination in sediments and their ovarian development was monitored during the 1989-1991 spawning seasons. In these fish, egg weight was negatively correlated with levels of PCBs in the liver. However, contaminant exposure levels were not significantly associated with the probability of entering vitellogenesis or with gonadosomatic index, plasma estradiol concentrations, or fecundity. In the second study, gravid female soles were taken from Eagle Harbor. Sinclair Inlet, Yukon Harbor, and University Point (known spawning areas for rock soles), and hormonally induced to spawn in the laboratory. Eggs were fertilized with pooled sperm from reference males. Consistent with the first study's findings, fish from Sinclair Inlet, where sediments contain elevated concentrations of PCBs, produced eggs with significantly reduced weight. Furthermore, the overall spawning success of fish from the site with the highest level of AH contamination (Eagle Harbor) was significantly impaired. These findings suggest that environmental exposure to AHs and PCBs may reduce reproductive success in female rock soles, but this species appears to be more resistant to such effects than other Puget Sound flatfish species, such as the English sole Pleuronectes vetulus.