Increased mitochondrial DNA diversity in ancient Columbia River basin Chinook salmon Oncorhynchus tshawytscha

The Columbia River and its tributaries provide essential spawning and rearing habitat for many salmonid species, including Chinook salmon (Oncorhynchus tshawytscha). Chinook salmon were historically abundant throughout the basin and Native Americans in the region relied heavily on these fish for thousands of years. Following the arrival of Europeans in the 1800s, salmon in the basin experienced broad declines linked to overfishing, water diversion projects, habitat destruction, connectivity reduction, introgression with hatchery-origin fish, and hydropower development. Despite historical abundance, many native salmonids are now at risk of extinction. Research and management related to Chinook salmon is usually explored under what are termed “the four H’s”: habitat, harvest, hatcheries, and hydropower; here we explore a fifth H, history. Patterns of prehistoric and contemporary mitochondrial DNA variation from Chinook salmon were analyzed to characterize and compare population genetic diversity prior to recent alterations and, thus, elucidate a deeper history for this species. A total of 346 ancient and 366 contemporary samples were processed during this study. Species was determined for 130 of the ancient samples and control region haplotypes of 84 of these were sequenced. Diversity estimates from these 84 ancient Chinook salmon were compared to 379 contemporary samples. Our analysis provides the first direct measure of reduced genetic diversity for Chinook salmon from the ancient to the contemporary period, as measured both in direct loss of mitochondrial haplotypes and reductions in haplotype and nucleotide diversity. However, these losses do not appear equal across the basin, with higher losses of diversity in the mid-Columbia than in the Snake subbasin. The results are unexpected, as the two groups were predicted to share a common history as parts of the larger Columbia River Basin, and instead indicate that Chinook salmon in these subbasins may have divergent demographic histories.Ye

Fish Passage Assessment & Barrier Removal to Improve Connectivity on the Lolo National Forest

The goal of the Lolo National Forest Fisheries Program is to conserve and restore native fish habitat and populations. An integral part of this goal is to build a strong program focused on removing barriers and restoring connectivity for fluvial westslope cutthroat trout and bull trout. Culverts used for stream crossings create temporary, partial, or seasonal barriers to fish passage, while others may preclude movement of fishes year-round. They can deny access to seasonally critical habitats, fragment populations, and suppress the recovery of populations following disturbance. Along with being fish passage barriers, undersized culverts can also lead to chronic stream degradation, increased erosion and sedimentation, and eventually road failures. To address these issues, we implemented an extensive survey of all road crossings of fish bearing streams on the forest in 2002 and 2003. Crews surveyed 696 culverts on the forest. The results showed that 592 (85.1%) of the culverts on the LNF are barriers to juvenile fish passage, while 602 (86.5%) culverts are barriers to adult passage. Attempting to address stream and population fragmentation, we have completed numerous culvert removal/replacement projects since 1995. Examples of projects across the forest include: Siegel Creek, where an undersized pipe was removed and the road obliterated above; Schwartz Creek, where two side-by-side culverts were removed, opening 5 miles of mainstem habitat; Lost Park Creek, where a 6-foot culvert at the mouth was replaced with a single-span bridge, opening up the entire mainstem; and, Surveyor Creek, where two high priority pipes were removed, opening 1 mile of habitat. This winter (2005), we will be developing a prioritization process to help identify out-year projects and to create more opportunities to work with partners. The most significant hurdle facing us in restoring connectivity to these systems is the public acceptance of large-scale road removal projects and available funding. Through forest-wide barrier inventory and prioritization, we hope to raise awareness of the impacts of existing road systems and stream crossings, and the need for more funding to complete these important projects

Caryn Ackerman (Cramer Fish Sciences): Graphical design and layout Data Sources and Credits

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