Relationships between tissue contaminants and defense-related characteristics of oysters (Crassostrea virginica) from five Florida bays

Evidence linking bivalve defense responses with pollutant exposure is incre asing. Contaminant effects on immune or defense responses could influence t he ability of an organism to resist infectious disease. This study explored relationships between xenobiotic chemicals accumulated in oyster (Crassost rea virginica) tissue and various measures of putative oyster internal defe nse activities and physiological condition. Defense-related and physiologic al measurements were made on individual oysters collected from 22 sites at five Florida bays and pooled oyster tissue from each site was analyzed for polycyclic aromatic hydrocarbons (PAHs), polychlorinated biphenyls (PCBs), metals and certain pesticides. Chemical concentrations, physiological condi tion, and hemocyte and hemolymph characteristics varied across bays and amo ng sites within a bay. Within-bay comparisons showed that sites with high o yster defense-related activities often had accompanying high tissue concent rations of one or more classes of xenobiotic chemicals. Correlation analysi s performed across bays demonstrated significant positive relationships bet ween most defense-related characteristics and at least one contaminant, inc luding various PAH, PCB and trace metal analytes. In combination with other recent studies, these results strengthen the hypothesis that certain xenob iotic chemicals may be associated with elevated oyster hemocyte activities, even though the ultimate influence on disease resistance remains unknown. Published by Elsevier Science B.V.