Steelhead Kelt Reconditioning and Reproductive Success, 2008 Annul Report.

Hatch, Douglas R.

United States. Bonneville Power Administration.

关键词: Gonads;    Management;    Genetics;    Origin;    Juveniles;   

DOI  :  10.2172/962227
RP-ID  :  P111194
RP-ID  :  37075
RP-ID  :  962227

美国|英语

来源: UNT Digital Library

【 摘 要 】

Iteroparity, the ability to repeat spawn, is a natural life history strategy that is expressed by some species from the family Salmonidae. Current rates of observed steelhead Oncorhynchus mykiss iteroparity rates in the Columbia River Basin are severely depressed due to anthropogenic development which includes operation of the hydropower system and other habitat degradations. Artificial reconditioning, which is the process of culturing post-spawned fish (kelts) in a captive environment until they are able to reinitiate feeding, growth, and redevelop mature gonads, is evaluated in this study as method to restore depressed steelhead populations. To test the efficacy of steelhead kelt reconditioning as a management and recovery tool different scenarios were investigated ranging from very low intensity (collect and transport fish) to high intensity (collect and feed fish in captivity until rematuration). Examinations of gamete and progeny viability were performed for first-time spawners and reconditioned kelt steelhead. We have continued to examine reproductive success of reconditioned kelt steelhead in Omak Creek using microsatellite loci to perform parentage analysis on juvenile O. mykiss . The groundwork has also begun on developing a genetic analysis of the Yakima subbasin in order to determine steelhead kelt contribution by utilizing parentage analysis on a larger scale. A research and study plan has been developed cooperatively with the University of Idaho to determine the feasibility of steelhead kelt reconditioning program in the Snake River Basin. Analysis of management scenarios indicated that while no-term and short-term reconditioned kelts continue to perform well outmigrating to the ocean but returns from these groups have been low ranging from 0-12% during 2002-2008. Survival (56%) of fish in the long-term treatment in 2008 was the highest we have observed in this project. Analyzing the three different management scenarios within the Yakima River subbasin we determined that long-term reconditioning contributed the highest numbers of fish to the spawning run, and short-term reconditioning overall was the best of the transport releases to the ocean. However contributions to the spawning run by no-term or short-term groups was low in all years. This is the second successful year of kelt gamete and progeny analysis. Initial limited results suggest that reconditioned kelts may have shown limited improvement in both egg quantity and/or quality. There is further evidence to support the successful spawning of steelhead kelts in the wild at Omak Creek. Yakima kelts have been successfully identified to stream origin using genotypes.