Decreased sperm count and sexual behavior in mosquitofish exposed to water from a pesticide-contaminated lake.

A number of reproductive abnormalities have been observed in wildlife living in Lake Apopka, Florida, USA. To test whether these abnormalities can be attributed to compounds in the water, we exposed male mosquitofish from Boulware Spring (Alachua County, Florida) to water from Lake Apopka and two reference sites, Orange Lake and Boulware Spring, for 1 month. Subsequently, sperm counts, sexual behavior, and sex hormones (testosterone and 17beta-estradiol) were measured. A lower sperm count and disrupted sexual behavior were found in fish exposed for 1 month to water from Lake Apopka, compared to those at the reference sites. Furthermore, sexual behavior and whole-body testosterone concentrations were correlated, suggesting androgen influences on the behaviors examined. We hypothesize that the presence of contaminants with antiandrogenic and estrogenic action in the water from Lake Apopka are the likely cause of the observed decrease in sperm count and impaired sexual behavior.