show Abstracthide AbstractAs a life-long resident of estuaries, Fundulus heteroclitus is routinely exposed to high levels of contaminants from industrial, agricultural, and municipal sources, and therefore are used to assess hazards due to metals, PAHs, PCBs, PBDEs, and dioxins. F. heteroclitus has large outbred natural populations resident in estuaries that are close to very large human population centers. Populations harbor natural variation in tolerance to pollution, and can serve as models to study the genomic basis of natural variation in sensitivity to the toxic effects of pollution.