Genetic structure of Fundulus heteroclitus from PAH-contaminated and neighboring sites in the Elizabeth and York Rivers.

Population genetic characteristics of mummichog, Fundulus heteroclitus, from the heavily industrialized Elizabeth River and nearby York River (Virginia USA) were assessed relative to sediment PAH concentrations. Allozyme genotype frequencies for all loci were consistent with random mating expectations at each locality and age class. Fish from all sites had comparable levels of enzyme polymorphism and heterozygosity regardless of the associated sediment PAH concentrations. Allozyme frequencies for 12 of 15 loci were homogeneous for mummichog from all localities except that allozyme frequencies were significantly different for the Idh-2 locus of (adult and juvenile) mummichog at the heavily-contaminated Atlantic Wood site relative to all other sites. Additionally, allele frequency differences were noted for Ldh-C and Gpi-1 among juvenile mummichog. Values for F(st) were 0.0254 and 0.0141 in the juvenile and adult samples, respectively, indicating greater among-locality genetic differentiation for juvenile mummichog than for adults. Juvenile mummichog are more likely to remain in their natal area while adult samples reflect movement of fish during two or more winter seasons. Correlation analysis suggested that genetic differentiation was not correlated with geographic distance at the spatial scale studied here; however, there was a significant correlation between genetic distance and differences among sites in organic carbon-normalized PAH concentrations. Mummichog collected at the heavily PAH-contaminated AW locality were genetically distinct from those at neighboring sites.