2009 Annual Report: Steelhead Kelt Reconditioning and Reproductive Success
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). Examination of gamete and progeny viability continued on first-time spawners and reconditioned kelt steelhead. Initial results suggest that egg quantity and/or quality is similar. Reproductive success of three reconditioned kelts that returned to and spawned naturally in Omak Creek has been verified using microsatellite genotyping and parentage analysis of juvenile O. mykiss. Yakima River kelts have been successfully identified to stream origin using microsatellite genotyping and GSI (Genetic Stock Identification) analysis. Identification of areas with higher rates of iteroparity such as Satus Creek will increase the statistical power for detection of kelt progeny. The Columbia River Inter-Tribal Fish Commission along with the Nez Perce Tribe and the University of Idaho have expanded research into the Snake River 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 Nez Perce Tribe is developing a steelhead kelt master management plan for the Snake 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. Improvements were made to the juvenile bypass at Lower Granite Dam to improve passage and collection of adult steelhead outmigrating as kelts. Additionally, we are designing an approach to identify specific hormones associated with reproductive status for screening kelts and assigning them to specific management actions.
Branstetter, R., J. Stephenson, A. Pierce, D.R. Hatch. 2010. 2009 Annual Report: Steelhead Kelt Reconditioning and Reproductive Success. U.S. Dept. of Energy Bonneville Power Administration Report Project #2007-401-00. Columbia River Inter-Tribal Fish Commission Technical Report #10-13. 162p.
Jun 29th, 2010