Steelhead Kelt Reconditioning and Reproductive Success 2010 Annual Report
Iteroparity, the ability to repeat spawn, is a natural life history strategy expressed by some species from the family Salmonidae. Observed iteroparity rates for steelhead Oncorhynchus mykiss in the Columbia River Basin are currently depressed due to anthropogenic development including operation of the hydropower system and other habitat degradations. Reconditioning post-spawned fish (kelts) in a captive environment to encourage reinitiating feeding, growth, and redevelopment of gonads is evaluated in this study as an approach to restore depressed steelhead populations. To test the efficacy of utilizing steelhead kelt as a management and recovery tool, different scenarios were investigated ranging from little intervention (collect and return fish to river) to high intensity (collect and feed fish in captivity until rematuration). Transport of Yakima and Snake River steelhead resumed with an attempt to move kelts further downriver, initial results are mixed and additional study should provide better results. Examination of gamete and progeny viability continued on first-time spawners and reconditioned kelt steelhead with results continuing to suggest that egg quantity/quality and juvenile factors are similar. Successful reproduction has been confirmed for 3 of 4 reconditioned kelts detected in Omak Creek. Genetic analysis confirmed that Naches and Toppenish kelts had more frequent post release PIT tag detections at Prosser Dam. The Columbia Inter-Tribal Fish Commission along with the Nez Perce Tribe and the University of Idaho are continuing with research in the Snake River Basin to determine which kelt reconditioning methods may be helpful in improving kelt survival in that basin and working to innovate new approaches that may benefit the entire Columbia River Basin. The University of Idaho (Idaho Cooperative Fish and Wildlife Research Unit) is testing transportation options and evaluating plasma factors in relation to life history stage of steelhead to optimize kelt survival and reproductive contribution. Sex hormone analysis appears to be able to give a predictive capability to determine if kelts will spawn within the year. The Nez Perce Tribe is continuing to develop a steelhead kelt master management plan for the Snake River Basin.
Hatch, D., R. Branstetter, J. Stephenson, A. Pierce, B. Bosch, D. Fast, J. Blodgett, S. Everett, R. Dasher, C. Baker, C. Moffitt, and J. Nagler. 2010. Steelhead Kelt Reconditioning and Reproductive Success 2010 Annual Report. Columbia River Inter-Tribal Fish Commission Technical Report 11-21, Portland, Oregon. 231p.