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PREDICTING THE OCCURRANCE OF ADAPTATION TO DIOXINLIKE COMPOUNDS IN POPULATIONS OF THE ESTUARINE FISH FUNDULUS HETEROCLITUS
Citation:
Nacci, D E., D M. Champlin, L Coiro, R A. McKinney, AND S Jayaraman. PREDICTING THE OCCURRANCE OF ADAPTATION TO DIOXINLIKE COMPOUNDS IN POPULATIONS OF THE ESTUARINE FISH FUNDULUS HETEROCLITUS. ENVIRONMENTAL TOXICOLOGY AND CHEMISTRY 21(7):1525-1532, (2002).
Description:
A population of the non-migratory estuarine fish species Fundulus heteroclitus (mummichog) indigenous to a polychlorinated biphenyl (PCB)-contaminated Superfund site (New Bedford Harbor, NBH, MA, USA) demonstrates an inherited tolerance to local, dioxin-like contaminants (DLCs). These findings suggest that DLCs have acted as selective agents, allowing the survival of only the most tolerant individuals, forming DLC-adapted populations. We hypothesized that 1) DLC-tolerant mummichog populations would reside where local conditions are toxic to sensitive individuals, and 2) toxic environmental conditions could be predicted based on responses of sensitive early life stages to laboratory exposures of DLCs . As a measure of DLC tolerance, progeny of field-collected fish were tested in the laboratory with a dioxin-like PCB congener, 3,3'4,4',5-pentachlorobiphenyl (PCB126). Mummichog populations were collected from sites with sediment PCB concentrations predicted to range from non-toxic to toxic. Consistent with predictions, tolerant populations were indigenous to sites with elevated sediment PCB concentrations. Also, as predicted, DLC-tolerant populations were resident to sites far less contaminated than the Superfund site. These results suggest that exposures to persistent, bioaccumulative and toxic contaminants may be producing evolutionary effects on a geographic scale larger than previously envisioned. This study presents an approach and describes a model system that may improve our understanding of the scale of occurrence for these potentially irreversible ecological effects.