Kelt Reconditioning and Reproductive Success Evaluation Research – 2018 Annual Technical Report
The Kelt Reconditioning and Reproductive Success Evaluation Project is a research, monitoring, and evaluation (RM&E) uncertainties category project funded through the Columbia Basin Fish Accords. The objectives are to evaluate methodologies to produce viable artificially reconditioned repeat steelhead spawners and to determine the productivity of repeat spawners. Work occurs in both the Yakima and Snake river basins. We focused on collecting steelhead kelts at juvenile bypass facilities in Prosser and Lower Granite dams, and additionally some fish were collected at Dworshak National Fish Hatchery. These kelts were reconditioned (given prophylactic treatments and fed a specially formulated diet) at Prosser and Dworshak National Fish Hatcheries. Survival of long-term reconditioned kelts has been 42% (19 years) for Yakima River at Prosser Hatchery and 33% (8 years; 43% over the last 6 years) for mixed stock collections at Lower Granite Dam, and in previous years Fish Creek and the South Fork Clearwater River. In 2018 unmarked upstream migrant adult steelhead return counts were at the 5th lowest across the region since records were kept in this regard in the mid 1990’s. These low return years typically translates into a lower abundance of kelts. Regardless, we collected a sizeable number of kelts at both the Snake and Yakima rivers due to lower water conditions which means that more kelts migrated via juvenile bypass systems. A total of 107 reconditioned B-run steelhead were released below Lower Granite Dam in 2018 to address Reasonable and Prudent Alternative 33 of the FCRSP Biological Opinion. A total of 106 reconditioned, remature steelhead were released in the Yakima River in 2018. Reproductive success of reconditioned steelhead was confirmed in the Yakima River once again with assignments of 46 juvenile fish to 27 unique kelt parents. Lifetime reproductive success for female reconditioned kelt steelhead was estimated as 2.36 relative to single time spawning steelhead. Using estradiol assays, we have established that steelhead rematuration rates vary annually and spatially and ranged from 41.7% for Snake River consecutive spawners while at 43.3% for upper Columbia and 65.2% for Prosser in 2018. Skip spawner rematuration rates in comparison are typically higher and where so at both the Snake and Upper Columbia sites 78.4% and 100% respectively, while they were lower than has been typically observed at Prosser (50%). Survival of skip spawners at Prosser has been very low and we are working on ways to improve survival of skip spawners at this location. Work continues with the Yakama Nation VSP study to determine plasma hormone levels of maiden fish so that we have a baseline with which to compare kelt to and tie these values to migration success, homing fidelity, spawn timing, and genetic stock index (GSI) structure in the basin. Differences in hormonal analysis for consecutive and skip spawners was compared. We discovered that consecutive spawners tended to recover a number of the hormones necessary for oogenesis much more rapidly than skip spawners. Skip spawners though did have much higher concentrations of muscle lipids, plasma triglycerides, and estradiol than consecutive spawners, which would allow for a greater reproductive investment. Post spawning survival was contingent on both high counts of triglycerids and plasma osmolality. Also, consecutive spawning condition was dependent during the period immediately after spawning. Among fish on the consecutive spawning trajectory, egg size is set first based on condition at approximately 10 weeks after spawning, and then fecundity (and consequently TEM) is set based on condition at approximately 20 weeks after spawning. Females with greater maiden reproductive investment were more likely to mature as consecutive spawners, suggesting that both reproductive investment and consecutive spawning may be condition-dependent traits, and raising the key question of when condition influences these outcomes. We also tested fasting of steelhead kelts during the first 10 weeks after spawning which did not result in significantly reduced maturation rate in this study. This supports that the critical period for the rematuration decision occurs before spawning in steelhead kelts. We continued to refine our plasma assays that detect IGF-I and GH concentrations that we utilize for evaluating kelt maturation. From 2008 to 2017 we have detected conclusive evidence of 342 kelts showing strong site fidelity from both aforementioned waterways. Most of 2018 implementation of the kelt master plan for the Snake River has been in process with Bonneville Power Administration. Development of a Snake River kelt reconditioning facility preliminary design has been ongoing with BPA in 2017 into 2019. Once the preliminary design is completed, we will move to the final stage of the ISRP 3-step process. Development of a kelt population model continues to make progress with simulations of kelt reconditioning in the Yakima River. The results of these simulations are preliminary and are built on extremely limited data sets, so results should not be considered definitive. The CRITFC and its member Tribes steelhead kelt reconditioning program continues to forward the science and inform the management of iteroparous O. mykiss in the Columbia River Basin. An extensive list of our work is compiled in the Adaptive Management and Lessons Learned section of this report. Also, our team published 2 papers and gave 14 professional presentations in 2018/19.
Hatch, D., R. Branstetter, J. Stephenson, A. Pierce, R. Lessard, J. Newell, A. Matala, W. Bosch, S. Everett, N. Graham, L. Medeiros, L. Jenkins, B. Hoffman, N. Hoffman, T. Cavileer, J. Nagler, M. Fiander, C. Frederickson, J. Blodgett, D. Fast, and R. Johnson. Kelt Reconditioning and Reproductive Success Evaluation Research. 1/1/2018 – 12/31/2018 Bonneville Power Administration Annual Report, 2007-401-00. 164p.