Inducibility of spawning and reproductive success of female english sole ( parophrys vetulus) from urban and nonurban areas of puget sound, Washington

Abstract

Vitellogenic female English sole were sampled from four areas in Puget Sound that varied in the nature and degree of chemical contamination. The fish were then injected with an analogue of Luteinizing Hormone Releasing Hormone (LHRH) in the laboratory to induce spawning. Ability to spawn, time to spawn, larval viability, and initial concentrations of plasma estradiol and vitellogenin [measured as alkaline-labile protein associated phosphate (ALP)] were assessed. In general, low initial plasma estradiol and ALP concentrations and subsequent reproductive impairment were most common in English sole from sites where levels of sediment contaminants [e.g. polycyclic aromatic hydrocarbons and polychlorinated biphenyls (PCB)] and measures of contaminant exposure in fish (hepatic PCB concentrations and aryl hydrocarbon hydroxylase activity) were highest, and where pollution-associated liver lesions in fish (i.e. neoplasms, foci of cellular alterations, specific degeneration/necrosis, and storage disorders) were most prevalent. Additionally, the time to spawn was found to be inversely correlated with initial plasma estradiol concentrations. Spawning success was found to be positively correlated with initial plasma estradiol and ALP concentrations as determined by logistic regression analysis; nearly 62% of the variability in the spawning response could be accounted for by these factors. Fertilization success was also found to be positively correlated with initial ALP concentrations, whereas fish captured from contaminated sites produced lower proportions of normal larvae. Overall, these findings suggest that contaminant exposure may result in poor reproductive success of female English sole. This may be related to a hormone imbalance or to slower ovarian development (non-synchronous timing) of female English sole from contaminated sites.