Feminizing effects of ethinylestradiol in roach (Rutilus rutilus) populations with different estrogenic pollution exposure histories.

Experimental exposures aimed at assessing the risks posed by estrogens in waste-water treatment work (WwTW) effluents to fish populations have rarely considered whether populations differ in their sensitivity to estrogenic compounds. This is despite evidence that selection at genes involved in the estrogen response has occurred in wild populations, and evidence that genotype can influence estrogen-response. In this study we compare the effects of a two-year exposure to a low measured concentration (1.

Investigation into Adaptation in Genes Associated with Response to Estrogenic Pollution in Populations of Roach () Living in English Rivers.

Exposure of male fish to estrogenic substances from wastewater treatment works (WwTWs) results in feminization and reduced reproductive fitness. Nevertheless, self-sustaining populations of roach () inhabit river stretches polluted with estrogenic WwTW effluents. In this study, we examine whether such roach populations have evolved adaptations to tolerate estrogenic pollution by comparing frequency differences in single-nucleotide polymorphisms (SNPs) between populations sampled from rivers receiving either high- or low-level WwTW discharges.

Riverine fish diversity varies according to geographical isolation and land use modification.

Understanding the environmental factors driving species-genetic diversity correlations (SGDCs) is critical for designing appropriate conservation and management strategies to protect biodiversity. Yet, few studies have explored the impact of changing land use patterns on SGDCs specifically in aquatic communities. This study examined patterns of genetic diversity in roach ( L.

Populations of a cyprinid fish are self-sustaining despite widespread feminization of males.

Background: Treated effluents from wastewater treatment works can comprise a large proportion of the flow of rivers in the developed world. Exposure to these effluents, or the steroidal estrogens they contain, feminizes wild male fish and can reduce their reproductive fitness. Long-term experimental exposures have resulted in skewed sex ratios, reproductive failures in breeding colonies, and population collapse.

Additional treatment of wastewater reduces endocrine disruption in wild fish--a comparative study of tertiary and advanced treatments.

Steroid estrogens are thought to be the major cause of feminization (intersex) in wild fish. Widely used wastewater treatment technologies are not effective at removing these contaminants to concentrations thought to be required to protect aquatic wildlife. A number of advanced treatment processes have been proposed to reduce the concentrations of estrogens entering the environment.