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Steelhead trout, considered part of the salmon family and currently a listed population under the Endangered Species Act, are unique from other anadromous fish in this respect: They have the ability to spawn more than once.
Fish managers for the Columbia River Inter-Tribal Fish Commission hope that this characteristic, called iteroparity, can be encouraged to enhance steelhead populations and restore an important life history pattern in the Columbia River Basin. The Kelt Reconditioning Project, sponsored by CRITFC, is providing valuable research to support this premise.
The project began in 1999 when CRITFC, in collaboration with the Yakima/Klickitat Fisheries Project, captured wild emigrating kelt steelhead from the Yakima River to test the possibility that ?reconditioning? post-spawn fish would improve their ability to spawn again. Post-spawn steelhead, or kelts, are kept in a captive environment and nurtured to encourage their feeding, growth, and redevelopment of reproductive organs. The techniques were initially developed for Atlantic salmon and sea trout.
Although historical rates of iteroparity for Columbia River steelhead are not well documented, from 1956 to 1964 outmigrating steelhead averaged 50 percent of the total upstream runs in the Clackamas River.
Current rates for Columbia River Basin steelhead are considerably lower due largely to the high mortality of downstream migrating kelts at dams. Fish passage facilities have never been designed for downstream moving adult steelhead, however large numbers of steelhead are seen every year in the juvenile bypass systems on the mainstem dams. This project is seizing the opportunity to rejuvenate wild fish that would have died so they can contribute again to the spawning run.
The project has investigated a variety of reconditioning and transportation strategies to evaluate a suite of potential steelhead management alternatives. Recently, a collaborative study to measure the reproductive success of reconditioned kelt steelhead has been initiated by CRITFC and cooperating tribes. Using parentage analysis based on DNA-typing the studies will determine if artificial reconditioning affects reproductive success.
Initial research established that kelt reconditioning not only worked, it substantially bolstered the number of repeat spawners in the Yakima River. During 2000, the Yakama Nation collected 512 wild kelts (38 percent of the subbasin's run that year) for reconditioning at Prosser Hatchery. Kelt rematuration rates in captivity have been 21 percent in 2001, 50 percent in 2002, and 85 percent in 2003.
In addition, the research is giving fish managers a greater understanding of kelt husbandry, food type preference, condition, and rearing environments. Since the project's beginning, 20 to 30 percent of the total annual steelhead migration has been successfully reconditioned, and radio telemetry studies have demonstrated successful spawning migrations and redd construction. In terms of numbers, an additional 100 to 200 reconditioned steelhead females could spawn a second time (a projected 300,000 to 600,000 additional eggs at an estimated 3,000 eggs per female) each year in the Yakima River.
it's still too early to know what the total contribution of reconditioning will be in rebuilding populations of steelhead in the basin. But these early results are encouraging and provide important clues about a life history strategy that may be one key to increasing the number of listed steelhead in the Columbia River Basin.
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