An Evaluation of the Reproductive Success of Natural-origin, Hatchery-origin and Kelt Steelhead in the Columbia Basin: 2006 Annual Report
We conducted a field study to investigate the reproductive success of hatchery, wild, and artificially reconditioned kelt steelhead. Three sites (Omak Creek, WA; Section Corner Creek, WA; and Shitike Creek, OR) were chosen to provide replicates to evaluate reproductive success of Oncorhynchus mykiss. Potential adults and progeny were sampled in each drainage and genotyped with 16 microsatellite loci to determine parentage.
In Omak Creek, two of three reconditioned kelts released in fall of 2005 returned in 2006. If they successfully reproduced, their progeny should be detectable in 2007 and 2008. Genetic evidence supports the presence of distinct resident and anadromous populations in Omak Creek. The combination of population and parentage assignment tests showed that Mission Falls may be a genetic barrier limiting the passage of adult steelhead. Twelve of the 21 juveniles sampled above Mission falls in 2005 were assigned to the anadromous population whereas no fish sampled above the falls in 2006 were assigned to the anadromous population. This may be the result of a velocity barrier at Mission Falls resulting from high water flows in 2006 but not in 2005.
In Section Corner Creek, all juveniles sampled were assigned to a single parental cross based on genetic identity and parentage analysis. Brood year 2005 juveniles were sampled as both fry in 2005 and parr in 2006 and matched to adults released in Section Corner Creek in 2005. Six female and five male parents contributed to the progeny sampled in each year. While the same fish contributed each year, there was a significant difference between the yearly distribution of progeny assigned to each individual. This difference was largely due to the differential survival or migration of progeny between females. Fewer adults contributed to reproduction in 2006 with only two females and two males contributing to the fry sampled. None of the kelt females were identified as parents of juveniles collected in either year, likely due to problems with rematuration timing during reconditioning. Further research is being completed to determine environmental cues and dietary needs of reconditioned kelts.
In Shitike Creek, juveniles collected at the screw trap were not successfully assigned to any of the potential anadromous parents. It is apparent that the sampled juveniles were not progeny of the anadromous population. Analysis of allele frequencies showed that the juveniles that were sampled in 2006 are more similar to and likely progeny of, the resident population in Shitike Creek. However, parentage analysis was not possible as the resident population is large and the majority of resident adults were not sampled. Juvenile sampling protocols will be expanded in 2007 to help identify anadromous progeny.
Stephenson, J., D. Hatch, R. Branstetter, J. Whiteaker, S. Narum, D. Fast, J. Blodgett, B. Bosch, M. Johnston, T. Newsome, D. Lind, B. Rogers, C. Fisher, R. Dasher, D. Best, J. Lovtang, and M. Gauvin. 2007. An evaluation of the reproductive success of natural-origin, hatchery-origin and kelt steelhead in the Columbia Basin. 2006 annual report. For the U.S. Dept. of Energy, Bonneville Power Administration, Project No. 2003-062-00. Columbia River Inter-Tribal Fish Commission Technical Report 07-5. 41p.