We scored six loci for over 50 specimens from a spawning population on the Rifle River. We analyzed this data to determine allele frequencies, observed and expected heterozygosity, genetic distance, and population substructure. We found one allele in the Rifle River that was observed in Saginaw Bay and not in any other spawning population. Observed heterozygosities were near expected values. The population was in HWE for five of the six loci. Genetic distances were low. Population substructure was extremely low (FST = 0.01). The results are consistent with at least moderate spawning site fidelity within the Saginaw Bay watershed.