Genetic Considerations for Recovery Criteria and Tasks for Gila trout, Oncorhynchus gilae

Authors: Thomas F. Turner

Year: 2016 (xlviii)

Abstract

The Gila trout recovery plan is currently undergoing revision. Since the last revision in 2003, an enormous amount of genetic data have been collected that could inform and help refine recovery criteria and tasks. We formed a discussion group of students, academics and resource managers to ask how genetic information could be better incorporated into the new recovery plan. We identified and addressed three major issues: hybridization and introgression, maintenance of genetic diversity in the face of loss due to disturbance, and genetic effects of a hatchery program for conservation of the species. We began by acknowledging that current levels of genetic diversity and genetic effective size in the species are below oft-cited thresholds (e.g., the 50/500 rule), and focused on balancing risks of introgressive hybridization against acute and chronic loss of genetic diversity using a decision-tree approach. We identified opportunities for restoration of demographic connectivity and gene flow among lineages as a potential ly important strategy for maintenance of diversity and vitality, but also realized that the impact of this strategy depends on securing appropriately sited and contiguous stream networks for recovery action. Finally, we evaluated risks and opportunities offered by conservation hatchery programs. Overall, we are optimistic that genetic information will be incorporated in a meaningful way to guide actions toward recovery and conservation of this iconic trout species.