Rimrock Lake Bull Trout Population Group: Difference between revisions
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The Rimrock Population Group consists of the three bull trout populations that occupy tributaries to Rimrock | === Overview === | ||
The Rimrock Population Group consists of the three bull trout populations that occupy tributaries to Rimrock Reservoir. Detailed information on each of these can be found here: | |||
[[Indian Creek Bull Trout Population|Indian Creek Population]] | [[Indian Creek Bull Trout Population|Indian Creek Population]] | ||
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[[North Fork Tieton Bull Trout Population|North Fork Tieton Population]] | [[North Fork Tieton Bull Trout Population|North Fork Tieton Population]] | ||
These three populations all make use of shared foraging, migration and overwintering (FMO) habitat in Rimrock | These three populations all make use of shared foraging, migration and overwintering (FMO) habitat in Rimrock Reservoir, and historically would have used downstream habitat in the Tieton and Naches watersheds. Information on conditions, threats and actions for this shared FMO habitat are detailed in the [[Rimrock Lake FMO Habitat|Rimrock Reservoir FMO]] page. | ||
=== Population Genetics === | |||
The three Rimrock local populations are moderately genetically differentiated from one another (M. P. Small et al., 2009, p. 13<ref>Small, M. P., et al. ''WDFW Yakima Bull Trout Report. Phase 3: Genetic Analysis of Yakima Basin Bull Trout (Salvelinus Confluentus)''. Washington Department of Fish and Wildlife, 2009, <nowiki>https://ybfwrb.org/wp-content/uploads/2017/10/Small_et_al_2009.doc</nowiki>.</ref>). The level of differentiation within Rimrock is high considering the close proximity of the three spawning tributaries, shared usage of Rimrock Reservoir as FMO habitat, historic lack of barriers between all three tributaries, and present-day lack of barriers between South Fork Tieton River and Indian Creek. These findings have been broadly interpreted to support the conclusion that there is high site fidelity, and correspondingly, low migration between populations and demographic independence. However, metrics of genetic connectivity are easily misinterpreted as indicators of demographic connectivity when population sizes are large or small (Gagnaire et al., 2015, p. 770<ref>Gagnaire, Pierre-Alexandre, et al. “Using Neutral, Selected, and Hitchiker Loci to Assess Connectivity of Marine Populations in the Genomic Era.” ''Evolutionary Applications'', 2015, <nowiki>https://doi.org/10.1111/eva.12288</nowiki>.</ref>; Lowe & Allendorf, 2010, p. 3042<ref>Lowe, Winsor, and Fred Allendorf. “What Can Genetics Tell Us about Population Connectivity?” ''Molecular Ecology'', vol. 19, 2010, pp. 3038–51, <nowiki>https://doi.org/10.1111/j.1365-294X.2010.04688.x</nowiki>.</ref>). Populations can maintain high differentiation despite substantial migration in the case of low effective population size, and while natal site fidelity is high within Rimrock, it is not complete. Small numbers of individuals collected in each of the Rimrock spawning tributaries originate from one of the other Rimrock populations and other individuals demonstrate admixture suggestive of past gene flow among Rimrock populations (M. P. Small & Martinez, 2011, p. 6<ref>Small, M. P., and E. Martinez. ''Interim Genetic Analysis of Yakima Basin Bull Trout''. 2011, <nowiki>https://ybfwrb.org/wp-content/uploads/2017/10/Small_and_Martinez_2011.pdf</nowiki>.</ref>). | |||
Connectivity and thus the potential for genetic exchange with downstream populations in the Naches River fluvial system was reduced by the construction of Tieton Dam in 1925. Recent work by USFWS (Beebe et. al 2024<ref>Beebe, Brittany, et al. ''Yakima Bull Trout Trap, Transport, and Monitoring Project 2022 Progress Report''. Progress, USFWS, MCFWCO, 2024, <nowiki>https://ybfwrb.org/wp-content/uploads/2024/11/Upper-Yakima-and-Tieton-Basin-Bull-Trout-Transport-Project_2022_Final.pdf</nowiki>.</ref>) indicates entrainment continues to occur in the Yakima Basin, however it is more well-documented in Upper Yakima when compared with Tieton dam. Although recent trap and haul efforts have not yielded a high sample size of bull trout captured below Tieton dam, Small et. al 2009 documented one-way gene flow out of Tieton basin into the nearest tributary, Rattlesnake Creek. It is possible entrained bull trout may be spawning with other fluvial populations in the Naches river system but the rate of downstream gene flow has not been well characterized. The construction of Tieton Dam in 1925 eliminated upstream passage and genetic contributions to Rimrock Reservoir populations from Naches fluvial populations. | |||
=== Population Monitoring === | |||
In a 2008 study by Mizell and Anderson, five adult bull trout were captured and radio-tagged in the N.F. Tieton River between Clear Lake and Rimrock Reservoir. An additional twelve bull trout were captured and tagged from the stilling basin below Tieton Dam during a fish salvage operation in 2005 during construction of the hydropower facility. All salvaged fish from below the dam were transported 22 miles downstream of Tieton Dam and released near the Wapatox Irrigation Diversion on the Naches River. The tagged N.F. Tieton bull trout migrated downstream and overwintered in Rimrock, and made spawning migrations toward Clear Creek Dam and into Indian Creek the following year. Radio tagged bull trout that were transported downstream to the Naches River primarily moved up the Naches toward the American River and Rattlesnake Creek. One bull trout attempted to go back up Tieton River but turned around and went back to the Naches river. The authors suggested that these fish essentially integrated within the existing fluvial populations in the Naches River. In the earlier bull trout tagging operation (Mizell et al. 2008<ref>Mizell, M., and E. Anderson. ''Monitoring Federally Listed Bull Trout (Salvelinus Confluentus) Movements Proximate to Bureau of Reclamation Dams in the Yakima Basin''. WDFW Submitted to USBR, 2008, <nowiki>https://ybfwrb.org/wp-content/uploads/2017/10/Mizell_Anderson_2008.doc</nowiki>.</ref>) bull trout were tagged and immediately released below Tieton Dam. These fish did not leave the area, but instead they stayed in or near the stilling basin. | |||
The US Fish and Wildlife Service began PIT-tag monitoring and genetic assignment of Rimrock bull trout populations at Clear Creek Dam and the North Fork Tieton River in 2012. The work indicated the need for new upstream fish passage at the dam. As an interim solution, Reclamation funded the US Fish and Wildlife Service to initiate a Trap and Haul program at the dam in 2016 until design and construction of a new fish ladder is complete. As a part of the program, PIT-monitoring continued in the upper and lower North Fork Tieton River and PIT antennas were installed in the upper and lower South Fork Tieton River and in lower Indian Creek. All bull trout collected below the dam are PIT tagged and tissue samples are collected for population assignment by the US Fish and Wildlife Service’s Abernathy Fish Technology Center. In 2024 as a part of a broader Tieton Dam Fish passage assessment by the US Geological Survey, the US Fish and Wildlife Service acoustically tagged 5 South Fork Tieton River and 5 Indian Creek origin bull trout and released them downstream of the Clear Creek Dam stilling basin. Five of the fish were detected in Rimrock Reservoir and three of the five spent considerable time in the Tieton Dam forebay from late October to early December. | |||
=== Shared Threats === | |||
Find shared threats to the Rimrock bull trout Populations under the Rimrock Reservoir FMO Habitat page. | |||
=== Shared Recovery Actions === | |||
Recovery actions for individual populations and shared FMO are highlighted on the corresponding pages. Shared actions that extend beyond the current FMO are 1) provision of two-way volitional passage at Tieton Dam, which would reconnect the Rimrock populations with FMO habitat downstream of the dam and the Naches bull trout populations, and 2) once connectivity is restored, recovery actions identified for the Naches populations that would then also potentially benefit the Rimrock populations. | |||
== Update Notes == | |||
This page was created during the 2025 BTAP update and was populated with some information from the 2012 BTAP. | |||
== References == | |||
Latest revision as of 16:19, 28 February 2025
Overview
The Rimrock Population Group consists of the three bull trout populations that occupy tributaries to Rimrock Reservoir. Detailed information on each of these can be found here:
These three populations all make use of shared foraging, migration and overwintering (FMO) habitat in Rimrock Reservoir, and historically would have used downstream habitat in the Tieton and Naches watersheds. Information on conditions, threats and actions for this shared FMO habitat are detailed in the Rimrock Reservoir FMO page.
Population Genetics
The three Rimrock local populations are moderately genetically differentiated from one another (M. P. Small et al., 2009, p. 13[1]). The level of differentiation within Rimrock is high considering the close proximity of the three spawning tributaries, shared usage of Rimrock Reservoir as FMO habitat, historic lack of barriers between all three tributaries, and present-day lack of barriers between South Fork Tieton River and Indian Creek. These findings have been broadly interpreted to support the conclusion that there is high site fidelity, and correspondingly, low migration between populations and demographic independence. However, metrics of genetic connectivity are easily misinterpreted as indicators of demographic connectivity when population sizes are large or small (Gagnaire et al., 2015, p. 770[2]; Lowe & Allendorf, 2010, p. 3042[3]). Populations can maintain high differentiation despite substantial migration in the case of low effective population size, and while natal site fidelity is high within Rimrock, it is not complete. Small numbers of individuals collected in each of the Rimrock spawning tributaries originate from one of the other Rimrock populations and other individuals demonstrate admixture suggestive of past gene flow among Rimrock populations (M. P. Small & Martinez, 2011, p. 6[4]).
Connectivity and thus the potential for genetic exchange with downstream populations in the Naches River fluvial system was reduced by the construction of Tieton Dam in 1925. Recent work by USFWS (Beebe et. al 2024[5]) indicates entrainment continues to occur in the Yakima Basin, however it is more well-documented in Upper Yakima when compared with Tieton dam. Although recent trap and haul efforts have not yielded a high sample size of bull trout captured below Tieton dam, Small et. al 2009 documented one-way gene flow out of Tieton basin into the nearest tributary, Rattlesnake Creek. It is possible entrained bull trout may be spawning with other fluvial populations in the Naches river system but the rate of downstream gene flow has not been well characterized. The construction of Tieton Dam in 1925 eliminated upstream passage and genetic contributions to Rimrock Reservoir populations from Naches fluvial populations.
Population Monitoring
In a 2008 study by Mizell and Anderson, five adult bull trout were captured and radio-tagged in the N.F. Tieton River between Clear Lake and Rimrock Reservoir. An additional twelve bull trout were captured and tagged from the stilling basin below Tieton Dam during a fish salvage operation in 2005 during construction of the hydropower facility. All salvaged fish from below the dam were transported 22 miles downstream of Tieton Dam and released near the Wapatox Irrigation Diversion on the Naches River. The tagged N.F. Tieton bull trout migrated downstream and overwintered in Rimrock, and made spawning migrations toward Clear Creek Dam and into Indian Creek the following year. Radio tagged bull trout that were transported downstream to the Naches River primarily moved up the Naches toward the American River and Rattlesnake Creek. One bull trout attempted to go back up Tieton River but turned around and went back to the Naches river. The authors suggested that these fish essentially integrated within the existing fluvial populations in the Naches River. In the earlier bull trout tagging operation (Mizell et al. 2008[6]) bull trout were tagged and immediately released below Tieton Dam. These fish did not leave the area, but instead they stayed in or near the stilling basin.
The US Fish and Wildlife Service began PIT-tag monitoring and genetic assignment of Rimrock bull trout populations at Clear Creek Dam and the North Fork Tieton River in 2012. The work indicated the need for new upstream fish passage at the dam. As an interim solution, Reclamation funded the US Fish and Wildlife Service to initiate a Trap and Haul program at the dam in 2016 until design and construction of a new fish ladder is complete. As a part of the program, PIT-monitoring continued in the upper and lower North Fork Tieton River and PIT antennas were installed in the upper and lower South Fork Tieton River and in lower Indian Creek. All bull trout collected below the dam are PIT tagged and tissue samples are collected for population assignment by the US Fish and Wildlife Service’s Abernathy Fish Technology Center. In 2024 as a part of a broader Tieton Dam Fish passage assessment by the US Geological Survey, the US Fish and Wildlife Service acoustically tagged 5 South Fork Tieton River and 5 Indian Creek origin bull trout and released them downstream of the Clear Creek Dam stilling basin. Five of the fish were detected in Rimrock Reservoir and three of the five spent considerable time in the Tieton Dam forebay from late October to early December.
Shared Threats
Find shared threats to the Rimrock bull trout Populations under the Rimrock Reservoir FMO Habitat page.
Shared Recovery Actions
Recovery actions for individual populations and shared FMO are highlighted on the corresponding pages. Shared actions that extend beyond the current FMO are 1) provision of two-way volitional passage at Tieton Dam, which would reconnect the Rimrock populations with FMO habitat downstream of the dam and the Naches bull trout populations, and 2) once connectivity is restored, recovery actions identified for the Naches populations that would then also potentially benefit the Rimrock populations.
Update Notes
This page was created during the 2025 BTAP update and was populated with some information from the 2012 BTAP.
References
- ↑ Small, M. P., et al. WDFW Yakima Bull Trout Report. Phase 3: Genetic Analysis of Yakima Basin Bull Trout (Salvelinus Confluentus). Washington Department of Fish and Wildlife, 2009, https://ybfwrb.org/wp-content/uploads/2017/10/Small_et_al_2009.doc.
- ↑ Gagnaire, Pierre-Alexandre, et al. “Using Neutral, Selected, and Hitchiker Loci to Assess Connectivity of Marine Populations in the Genomic Era.” Evolutionary Applications, 2015, https://doi.org/10.1111/eva.12288.
- ↑ Lowe, Winsor, and Fred Allendorf. “What Can Genetics Tell Us about Population Connectivity?” Molecular Ecology, vol. 19, 2010, pp. 3038–51, https://doi.org/10.1111/j.1365-294X.2010.04688.x.
- ↑ Small, M. P., and E. Martinez. Interim Genetic Analysis of Yakima Basin Bull Trout. 2011, https://ybfwrb.org/wp-content/uploads/2017/10/Small_and_Martinez_2011.pdf.
- ↑ Beebe, Brittany, et al. Yakima Bull Trout Trap, Transport, and Monitoring Project 2022 Progress Report. Progress, USFWS, MCFWCO, 2024, https://ybfwrb.org/wp-content/uploads/2024/11/Upper-Yakima-and-Tieton-Basin-Bull-Trout-Transport-Project_2022_Final.pdf.
- ↑ Mizell, M., and E. Anderson. Monitoring Federally Listed Bull Trout (Salvelinus Confluentus) Movements Proximate to Bureau of Reclamation Dams in the Yakima Basin. WDFW Submitted to USBR, 2008, https://ybfwrb.org/wp-content/uploads/2017/10/Mizell_Anderson_2008.doc.