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ACTIVATION OF OYSTER DEFENSES BY ENVIRONMENTAL CONTAMINANTS
Citation:
Fisher, W S. AND L M. Oliver. ACTIVATION OF OYSTER DEFENSES BY ENVIRONMENTAL CONTAMINANTS. Presented at National Shellfisheries Association Annual Meeting, Mystic, CT, April 14-18, 2002.
Description:
Four field studies performed on eastern oysters Crassostrea virginica support a hypothesis that Cu, Zn, and perhaps butyltins and polycyclic aromatic hydrocarbons (PAH) can stimulate hemopoiesis, hemocyte locomotion and hemocyte bactericidal capacity. The first study found circulating hemocyte numbers and locomotion were positively associated with contaminated sites in Tampa Bay, particularly those where pooled oyster tissues contained high concentrations of trace metal and PAH analytes. Subsequently, the relationships between these particular contaminants and hemocyte activities were extended to four additional bays (St. Andrew, Choctawhatchee, Pensacola, and Biscayne). A third study, which analysed chemicals from individual oysters in Pensacola Bay, verified that circulating hemocyte numbers and bactericidal activity were positively correlated with Cu, Sn, Zn, butyltin, total metals, total polychlorinated biphenyls and total PAH. A fourth study showed that circulating hemocyte number and bactericidal activity were significantly elevated when oysters were moved from a relatively clean site to one with high concentrations of Cu, Zn, butyltins and PAH. These
data provide a weight of evidence that certain chemical contaminants can stimulate defense-related hemocyte activity in oysters. Although chemical contaminants are generally suspected to suppress defense functions of oysters, these chemicals, for unknown reasons, appear to have the opposite effect.