White sturgeon CAcipenser transmontanus) are a long-lived, primitive fish species which forage primarily along the river bottom of large river systems in the Pacific Northwest. Historically, as an anadromous species, they could distribute downstream to feed in the rich estuary or marine areas and then migrate back up the river to spawn. With the historic river becoming a series of flooded impoundments, sturgeon were denied open river access, but they appear to have been able to adapt to the altered environment. White sturgeon are found throughout the Columbia River and are thought to be successfully reproducing in some of the impoundments. In those reservoirs where little or no reproduction takes place, enhancement hatcheries may be an option for use in rebuilding isolated populations. However, the degree of stock specificity that exists in the Columbia River was unknown and precluded the use of the more abundant lower river fish as a common egg source to repropagate the upper river unless genetic similarity could be demonstrated among sturgeon throughout the river system. To resolve the issue, research was conducted to determine what level of genetic differentiation exists among sturgeon in the Columbia River system, using starch gel electrophoresis to enable a baseline of population genetic structure data to be assembled. A greater diversity in electrophoretic pattern was observed in the lower portions of the river.The bulk of the qualitative variability we noted was consistent throughout all sections of the river. Some specific quantitative differences were apparent between the areas we examined. Interpretation of the results was complicated by the fact that dam construction would tend to isolate and mix stocks by preventing the migration of fish returning upstream.

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