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EFFECTS OF ATRAZINE ON THE REPRODUCTIVE SUCCESS IN THE MARINE FISH, CUNNER(TAUTOGOLABRUS ADSPERSUS)
Citation:
Mills, L J., R E. GutjahrGobell, D B. Horowitz, AND G Zaroogian. EFFECTS OF ATRAZINE ON THE REPRODUCTIVE SUCCESS IN THE MARINE FISH, CUNNER(TAUTOGOLABRUS ADSPERSUS). Presented at Society of Toxicology 42nd Annual Meeting, Salt Lake City, UT, March 9-13, 2003.
Description:
Atrazine, the most widely used herbicide in the world, leaches into ground water and surface runoff after agricultural and forestry applications. It has been detected in concentrations in the ppb range in ground water, surface waters, rivers, streams, and precipitation. Atrazine has also been reported to have endocrine disrupting activity, and is theorized to affect steroidogenesis in vertebrates by inducing aromatase, the enzyme complex that converts testosterone to estradiol. We tested the hypothesis that exposure to atrazine will affect reproductive success in a marine fish species, cunner (Tautogolabrus adspersus). During a one week pre-exposure period, cunner in spawning condition were monitored daily to determine egg production, egg fertility, and egg viability. Atrazine, mixed into a slow release matrix, was then implanted subcutaneously into each fish below the dorsal fin. Treatments were control (matrix only) and two nominal concentrations of atrazine, 0.5 and 5 mg/kg (500 and 5000 ppb, respectively). Each treatment consisted of four replicate tanks containing up to two male and three female fish. Eggs were collected daily and evaluated within 24 hours to determine total number, number fertile, and number developing normally (viable). At termination of the experiment, sperm motility was checked in males and blood was drawn from all fish. Fish were dissected to determine gonad and liver weights. Brain, gonad, liver and adipose samples were flash frozen and archived for later analysis. Results showed no significant differences between treatments or between pre- and post-exposure fish in daily female egg production, percent fertile eggs, and percent viable eggs. All males produced milt and had motile sperm. Likewise, there were no significant differences between treatments in average gonadosomatic and hepatosomatic indexes of female or male fish. While analysis of brains from these fish showed aromatase activity was significantly elevated in atrazine-exposed males, our reproductive data indicate that this type of short-term atrazine exposure did not immediately affect the reproductive success of mature cunner.