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2D - Mechanisms of Toxic Action (MO4/14) The Sub-lethal effects of Copper on Hybrid Striped Bass. Bielmyer, Gretchen 1, Tomasso, Joseph1, Gatlin, Delbert2, Klaine, Stephen1, 1 Clemson University, Clemson, SC, USA2 Texas A&M, Austin, Texas, USA ABSTRACT- Copper is an abundant trace metal and although beneficial at low levels, it is also potentially toxic to most aquatic organisms. Freshwater fishes are especially sensitive to copper due to direct branchial uptake. Mechanisms of toxicity and consequences of exposure vary due to uptake route (waterborne or dietary) and ionoregulatory status (seawater or fresh water acclimated). The overall objectives of this research were to determine the effects of copper via aqueous and/or dietary exposure in hybrid striped bass acclimated to freshwater and seawater conditions and to ultimately develop a model system to assess different contaminant exposure routes at different salinities in the same organism. Chronic six week experiments were conducted to determine the effects of aqueous, dietary, and combined aqueous and dietary copper exposure to both fresh and saltwater-acclimated hybrid striped bass. Growth and tissue copper accumulation were measured to characterize sub-lethal effects of copper. Significant decreases in growth were seen in both saltwater and freshwater-acclimated fish exposed to copper. Intestine and liver copper accumulation appeared to be good indicators of chronic sub-lethal copper exposure; gill copper was not significantly different from controls. The dietary route of exposure was significant in both fresh and saltwater, however, it was the main route for copper accumulation in saltwater-acclimated fish. Another experiment was conducted to determine the effects of increasing dietary copper in both fresh and saltwater fish, with growth and tissue copper accumulation as the measured end points. Key words: dietary, Fish, copper |
