Abstract The utility of using isozyme analysis to study the stock structure among West Coast populations of green sturgeon (Acipenser medirostris) was assessed. Isozyme analysis was not determined to be an adequate method for assessing stock structure in green sturgeon for the following reasons: 1) the complex nature of isozyme expression 2) the relatively poor resolution of enzyme systems for our samples 3) the invasive nature of collecting tissue samples for isozyme analysis, which necessitates sacrificing the fish, precludes collection of samples from some rivers. The stomach contents of 23 green sturgeon collected from fish harvested in the Klamath River were analyzed. Only four stomachs contained identifiable food items, with the others containing food far too digested for identification, gravel, or no contents. Two stomachs contained the small gastropod, Olivellapyna, one stomach contained the carapace remains of a female Dungeness crab, Cancer magister, and one stomach contained the posterior portions of three ammocoetes, Lampetra tridentata. Preliminary analysis was conducted using mtDNA to assess the potential of using this technique for assessing the stock structure of green sturgeon. Although the Klamath River Fishery Restoration Program did not fund this analysis, the results are presented because this work was designed to yield complementary information to the isozyme study. No diagnostic differences were detected between samples collected from the Klamath River and the Columbia River estuary using Restriction Fragment Length Polymorphism analysis. Study results indicated that microsateliite DNA analyst might be the most appropriate current genetic technique for assessing the population structure of green sturgeon.
"June 2000"