Watkins, Crystal (2011-12). Assessment of Mosquitofish (Gambusia affinis) Downstream of Domestic Wastewater Effluents in the Bayous of Harris County. Master's Thesis. Thesis uri icon


  • The introduction of pharmaceuticals and personal care products (PPCPs) to aquatic systems has impacted development and reproductive health of fish in many regions of the world. This study investigated western mosquitofish in the bayou systems of Harris County, Texas for evidence of morphological and reproductive abnormalities. Mosquitofish were sampled above and below WWTPs on five streams during May and August 2010, and specimens were dissected and analyzed for reproductive (egg/embryo weight, embryo/egg number and embryos staging), morphological (liver and gonad weight, body length, gonadosomatic index and hepatosomatic index) and histological indicator variables. In addition, water samples were analyzed for concentrations of PPCPs. Spatial and temporal variation was observed among all indicator variables, however no consistent differences were found above versus below WWTP discharges. Histopathology showed no evidence of lesions or presence of intersex individuals. Chemical analysis revealed a variety of pharmaceuticals and anthropogenic chemicals present in the Houston area waterways, however all were at concentrations lower than those known to cause impacts to fishes. These results suggest that the current concentrations of chemicals being discharged from WWTPs into headwater reaches of streams in the suburban area of west Houston are below levels that impact the physiology of male and female mosquitofish.

publication date

  • December 2011