You are here:
RELATIONSHIPS BETWEEN OYSTER (CRASSOSTREA VIRGINICA) DEFENSE MEASUREMENTS AND TISSUE CONTAMINANTS
Citation:
Oliver, L M., W S. Fisher, A. K. Volety, AND Z A. Malaeb. RELATIONSHIPS BETWEEN OYSTER (CRASSOSTREA VIRGINICA) DEFENSE MEASUREMENTS AND TISSUE CONTAMINANTS. Presented at 92nd Annual Meeting of the National Shellfisheries Association, Seattle, WA, 19-23 March 2000.
Description:
Bivalve mollusks such as Crassostrea virginica typically inhabit estuaries and coastal areas that are increasingly contaminated with anthropogenic chemicals. Oysters may bioaccumulate large quantities of metals, polyaromatic hydrocarbons (PAHs), and polychlorinated biphenyls (PCBs) without evident ill effects, but various measurments of bivalve defense activity show alterations from experimental chemical exposures and longer-term, field exposure to chemical mixtures. Forty oysters were collected from Bayou Chico and East Bay, two sites in Pensacola Bay, Florida, known to differ in the type and magnitude of chemical contaminants. Tissue concentrations of metals, tri- and di-butyltin (TBT, DBT), PAHs and PCBs were measured along with hemocyte number, phagocytic (PI) and bactericidal (KI) indices, and serum lysozyme and total protein levels. Hemocyte PI was significantly higher in East Bay oysters, which also had low tissue levels of PAHs, PCBs, TBT, DBT, and the metals Al, Cr, Fe, Ag, Cd, and Hg. Average hemocyte number, KI, serum lysozyme and protein were significantly higher in Bayou Chico oysters which also had high tissue concentrations of organic contaminants, butyltins, and Mn, Cu, Zn, and Sn. Canonical correlation analysis was used to examine relationships between tissue metals and defense measurements using linearly combined sets of variables. The highest possible correlation was positive: r = .934, between canonical variables composed of hemocyte number, PI, serum protein and lysozyme for defense, and Cd, Fe, Al, Pb, Zn, Mn, Sb, Ni, and Cr for metals. This suggestion of heightened defense activities in oysters from metal-contaminated sites is consistent with previous observations. The likelihood of complex relationships between oyster immune measurements and contaminant stress suggests that single chemical exposures and univariate analyses may be inadequate or misleading.