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|Insights in Mokelumne River Hatchery Steelhead (Oncorhynchus mykiss) Program Structure from Nonlethal Genetic Samples
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|@lauragexplorer for twitter and instagram
|Mokelumne River Hatchery Success
|Type of Presentation
Four Central Valley hatcheries were established in California to mitigate for dam construction and decreasing populations of local anadromous salmonids. Mokelumne River Hatchery (MRH), the smallest of the four programs, features a broodstock program of mixed ancestry from a history of imported eggs from other hatcheries to meet egg targets due to poor adult returns. The ability to discern biological patterns in migrating species has been increased with the advent of parentage-based tagging (PBT). We have implemented PBT at all four CV hatcheries since 2011, allowing pedigree reconstruction from nonlethal genetic samples collected from spawning adults at these hatcheries. These pedigrees enable analysis of program age structure, migration between hatcheries, as well as distribution of family sizes. From these data, we characterize MRH’s age structure, migration rates, and distribution of family sizes. MRH’s age structure has shifted from mainly two year old fish to feature a strong ratio of two and three year olds. Migration between hatcheries is relatively low, with the exception of one major straying event between MRH and Nimbus Hatchery. Additionally, relatedness amongst broodstock has been managed through real-time genotyping. Further work at MRH will investigate the genetic and epigenetic factors that affect life-history development in O. mykiss. These findings, along with hatchery history and the strong returns in the last few years suggest success in establishment of this program, but also illustrate the sometimes unpredictable nature of anadromous broodstock.