Eel River wild steelhead include fish from the Middle Fork Eel River and Van Duzen River. Chinook wild stocks include fish from Deer and Mild Creeks, the upper Scramento River, and the lower American River. Statistical analyses are given for differences in the frequency of mtDNA types between wild and cultured population pairs using likelihood chi-square tests. Moran et al. They did find that different restriction enzymes can be used to distinguish hatchery from wild populations.
Letters represent the fragment pattern generated by each restriction enzyme.
The behavioral, morphological and genetic differences observed by various researchers provide a strong foundation for understanding the success of hatchery supplementation programs. Results of the described studies favor wild fish over hatchery fish in behavioral components. Morphologically, hatchery and wild fish were also shown to be different, but the differences do not necessarily favor one type of fish. Genetically, wild populations exhibited less mtDNA variation than hatchery fish, but hatchery fish had less varied mtDNA fragment sizes. These studies will be of use in future experiments to determine how much genetic variability and morphological differences affect hatchery fish introduction into, and success in, the wild.