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DIFFERENTIAL RESPONSE TO BACTERIAL CHALLENGE IN POPULATIONS OF FUNDULUS HETERCLITUS FROM CLEAN AND POLLUTED SITES
Citation:
Nacci, D E., M Huber, S. Cohen, E. Gauger, AND M. GomezChiarri. DIFFERENTIAL RESPONSE TO BACTERIAL CHALLENGE IN POPULATIONS OF FUNDULUS HETERCLITUS FROM CLEAN AND POLLUTED SITES. Presented at Eastern Fish Health Workshop, Leetown, WV, April 24-26, 2001.
Description:
Mummichogs (Fundulus heteroclitus) indigenous to an urban estuarine Superfund site in New Bedford Harbor (NBH, MA, USA) contain extremely high concentrations of the local contaminants, polychlorinated biphenyls (PCBs). These fish populations apparently persist due to an inherited tolerance to some of the toxic effects of PCBs. However, it is not known whether this adaptation affords protection from all toxic effects produced by PCBs. While NBH
mummichogs appear healthy, unusual rates and incidences of internal parasites have been found in these PCB-tolerant mummichogs. Because PCBs have been reported to have immunosuppressant effects on fish and other vertebrates, we hypothesized that parasitism in NBH mummichogs might reflect poor immunological responsiveness due to high PCB tissue concentrations. To test this hypothesis, PCB-adapted murnmichogs were collected from NBH, and PCB-sensitive mummichogs were collected from a reference site near NBH, and an uncontaminated site distant from NBH. Responsiveness to immunological challenges was compared for sample populations by measuring short-term survival following injection of the cultured bacteria, Vibrio carchariae. In contrast to our predictions, PCB-tolerant NBH
populations were slightly, but consistently, more resistant to these bacterial challenges in comparison to fish from the uncontaminated populations. These results suggest that fish surviving PCB contamination and other stressors associated with the NBH site are not compromised in their response to bacterial challenge. Subsequent experiments will employ laboratory-raised, uncontaminated fish from these same populations to evaluate whether this differential survival pattern is inherited or whether it is associated with contaminant concentrations or other conditions affecting wild fish populations.