Significant but subtle differentiation was detected for both microsatellite DNA and mitochondrial DNA among four populations of American shad Alosa sapidissima. The data indicate that straying among rivers is sufficient to permit only marginal population differentiation in this species but suggest that individual river populations should be managed as distinct stocks. Comparison of the Hudson and Columbia populations the latter derived from the former over 100 years ago revealed only a slight reduction in microsatellite DNA variation for the founded population but halving of mitochondrial DNA consistent with the haploid maternal inheritance of the latter marker. The depleted and endangered James River (Virginia) population and two other Atlantic coast populations exhibited similar levels of microsatellite DNA variation but mtDNA diversity in the James River was marginally lower than in other Atlantic populations again consistent with the low effective population size of mtDNA. (C) 2000 The Fisheries Society of the British Isles.
ASJC Scopus subject areas
- Ecology, Evolution, Behavior and Systematics
- Aquatic Science