2005 Annual Report: An Evaluation of the Reproductive Success of Natural-origin, Hatchery-origin, and Kelt Steelhead in the Columbia Basin
We initiated a field study to investigate the relative reproductive success of artificially reconditioned kelt steelhead. Prior to an implementation of a large-scale steelhead kelt reconditioning program, it is important to evaluate the reproductive success of reconditioned kelts relative to hatchery and natural first time spawners. To assess kelt reproductive success, three sites (Satus Creek,WA; Omak Creek, WA: and Shitike Creek, OR) have been chosen to replicate studies of relative reproductive success of each variant of steelhead. Technological advances in DNA-typing make direct measurement of reproductive success using pedigree analysis practical. Employing these new techniques, our study will measure the reproductive success of natural-origin, hatchery-origin, and reconditioned kelt steelhead in natural stream settings. This will yield quantitative data replicated geographically and temporally that will add resolution to the issue.
The 2005 field season was the initial year of capturing, reconditioning, and analyzing kelts in the three subbasins. While we were successful in capturing and reconditioning kelts, the numbers and condition of kelts was unusually poor presumably due to lower than normal precipitation and flows. Physical evaluation and the collection of genetic material from first time spawning adults resulted in the capture of 113 adults at Omak Creek, 57 in Shitike Creek, and 68 from Satus Creek (retained steelhead destined for Section Corner and South Fork Logy Creeks). We detected 34 kelts attempting to outmigrate from Omak Creek, 39 kelts from Shitike, and 3 from Section Corner Creek. Kelts collected at Omak Creek did not survive to be reconditioned so post spawn steelhead from the localized broostock program were used and three were released in October of 2005. Ten kelts were collected for reconditioning from Shitike Creek and one survived to release in February 2006. None of the post spawn steelhead from Section Corner Creek survived to be reconditioned.
In 2005 we were able to collect parentage data in Section Corner Creek, because reconditioned kelt steelhead were available and the experiment site is analogous to a field laboratory. We released 16 steelhead into Section Corner Creek on March 9, 2005. This release was composed of five reconditioned female kelts, six female first time spawners, and five male first time spawners. Parentage analysis of 159 juveniles indicated that production was from first-time spawning females only. We believe that the reconditioned kelts were over ripe and did not spawn. These fish were held on well water with water temperatures that exceeded the river’s, likely accelerating their maturation. We are implementing procedures to more closely synchronize maturation levels from the two groups for future experiments. Parentage analysis for Omak and Shitike Creek will begin in 2006.
Hatch D. et al. 2006. 2005 Annual Report: An Evaluation of the Reproductive Success of Natural-Origin, Hatchery-origin, and Kelt Steelhead in the Columbia Basin. Columbia River Inter-Tribal Fish Commission Report reference #06-07, Portland, Oregon.