A hatchery program designed to compensate for the loss of nearly half the historical abundance of steelhead returning to the Snake River caused by the installation and operation of dams in the 1960s is “highly effective,” according to a recently released review by a panel of scientists. The scientists added that the program practices good science, uses sound actions and is adaptable to the changing conditions in the river.
The review of the Lower Snake River Compensation Plan by the Independent Scientific Review Panel said that the LSRCP steelhead program “has achieved impressive success in restoring and maintaining sport fisheries throughout the Snake River Basin, even in years when hatchery and natural adult returns are low for reasons beyond the program’s control.”
The ISRP’s review of the 50-year old LSRCP steelhead program was requested by the Northwest Power and Conservation Council in cooperation with the U.S. Fish and Wildlife Service.
While the LSRCP’s goal for annual adult steelhead returns is 55,100 wild fish, the number of steelhead actually returning to the Snake River basin has dropped ten-fold since the 2009-10 run year when 140,003 fish returned. The 2019-20 run year saw just 13,027 steelhead (this year, through Sept. 30, some 57,617 unclipped fish have passed Bonneville Dam, the largest to date in the last 10 years). Much of that decline, according to the review, is due to other influences.
However, the LSRCP steelhead hatchery programs over the past 14 run years (2009-10 to 2022-23) slightly exceeded their goals for adult returns on average, the review says. These high averages were driven in part by very high returns for three run years from 2009-10 to 2011-12. Moreover, the results varied greatly within and between hatchery programs. Overall, six of twelve programs achieved their goal.
The review says the LSRCP faces major challenges to mitigate the impacts of dams on salmon and steelhead populations in the Snake River Basin. The fish first must migrate long distances from Snake River tributaries to the ocean and coming back adults pass through six to eight hydropower dams and reservoirs to reach their spawning grounds. In addition, the survey says, “climate change and habitat degradation over the last 50 years have reduced freshwater and ocean productivity and caused major declines in salmon and steelhead populations throughout the Pacific Northwest.”
The ISRP completed a similar review of the LSRCP program for spring/summer Chinook salmon in 2023, finding that the number of spring/summer Chinook salmon adult returns produced by the eleven Lower Snake River Compensation Plan hatchery programs had declined by 75 percent since the program’s first years and, overall, has not produced the nearly 59,000 returning Chinook adults that is the program’s goal. According to the ISRP report, adult returns have declined from more than 40,000 spring/summer Chinook in early LSRCP years to less than 10,000 returning adults in 2017.
The “ISRP hopes its recommendations can help the program address its many daunting challenges and move the program closer to meeting its goals consistently,” the ISRP said in its review. “That stated, the ISRP understands that many of the challenges that limit success, especially post-release survival, cannot be fully addressed by LSRCP Program actions alone. The lack of consistent achievement of objectives in recent years is often despite, not because of, the extensive efforts of the program implementers.”
The LSRCP monitors and evaluates in-hatchery performance, annual adult returns, smolt-to-adult return (SAR), smolt-to-adult survival (SAS), straying, harvest, catch-escapement distributions, and ecological interactions with natural populations. It is a federal program designed to mitigate the impacts of construction and operation of the four lower Snake River federal dams (Ice Harbor, Lower Monumental, Little Goose, and Lower Granite) on Chinook salmon and steelhead populations in the Snake River Basin, the review says. This review is just of the steelhead program.
The LSRCP program rears steelhead at five separate hatchery production facilities and operates numerous adult collection and smolt acclimation facilities in Washington, Oregon and Idaho. These hatcheries are spread throughout all the major subbasins in the lower Snake River, including the Tucannon, Clearwater, Grande Ronde, Imnaha and Salmon as well as the Walla Walla subbasin in the mid-Columbia River.
The hatcheries are all owned by the U.S. Fish and Wildlife Service and the Service administers the program that is funded by the Bonneville Power Administration. However, operations of the hatcheries are by state, federal and tribal fish and wildlife agencies in the Columbia River basin.
The survey, “ISRP Review of the Lower Snake River Compensation Plan Steelhead Program, 2024-2025,” was published Sept. 22 and can be found on the Council website at ISRP_2025-3_LSRCPsteelheadReview19Sept.pdf
The ISRP has since 1997 conducted scientific reviews of projects one-by-one to judge whether they meet the requirements of the Council’s Columbia River Basin Fish and Wildlife Program. The panel’s advice is weighed as the Council decides which projects to recommend for funding. The Bonneville Power Administration funds the program as mitigation for impacts to fish and wildlife caused by the construction and operation of the federal Columbia/Snake river hydro system.
One of the strengths of the LSRCP hatchery program is the high level of in-hatchery performance, the survey says.
“Specifically, pre-spawning mortality of broodstock is low and green egg-to-smolt survival is excellent, exceeding the 65% percent goal on average in all hatcheries,” it says. “In general, most hatchery programs met their smolt production goals for 85% of the brood years. The excellent in-hatchery performance has little scope for improvement and indicates that alternatives for the LSRCP to address overall survival challenges through hatchery management changes are generally limited to improving rearing and release strategies to enhance smolt quality and smolt-to-adult survival.
“The mean SAR and percent of SAR goal achieved of individual programs varied greatly. The percent of goal achieved ranged from less than one-half to over two-times the target,” the survey added.
In the past, straying of LSRCP hatchery adults into areas where natural populations of steelhead are listed under the federal Endangered Species Act was a significant problem, but that declined significantly beginning with the 2012-13 return year. That’s due to less barging of out-migrating smolts. From the late 1980s through 2006 a high proportion of Snake River steelhead smolts were barged to the lower Columbia River. Then barging was greatly reduced and since then stray rates into Oregon’s Deschutes and John Day rivers have been negligible and within acceptable risk, the survey says.
However, the contribution to Columbia River mainstem fisheries by the LSRCP hatcheries were “lower in the most recent years than in the past due to low returns and harvest management changes,” the review says. In the project area, the LSRCP has continued to provide recreational harvest opportunities in Washington, Oregon, and Idaho, “although the number of fish harvested and the fishing effort was substantially lower than during the period prior to the last review in 2013.”
Among the factors that limit success of LSRCP goals and management objectives since the last review are:
— Recent smolt to adult returns have been low because of high mortality rates at multiple life stages in the life cycle following release of smolts.
— The low abundance of natural- and hatchery-origin steelhead adult returns in recent years has prevented achieving broodstock and smolt production objectives for some programs, especially the integrated broodstocks.
— There is limited hatchery rearing capacity and water availability to reduce rearing densities to improve smolt quality while maintaining current production goals.
— Monitoring is inadequate for the four supplementation programs, so the natural populations abundance and productivity responses to supplementation is unclear.
— Climate change will likely continue to influence smolt-to-adult survival, hatchery operations, and performance by reducing water supplies and creating frequent and severe flow variation and severe floods, influencing adult collection and acclimation facility operations.
— Funding availability hampers many aspects of hatchery operations, hatchery maintenance, infrastructure improvements, monitoring and evaluation, and adaptive management actions.
— Decreasing water supplies and deteriorating hatchery infrastructure at many facilities will continue to limit production capacity, rearing density indices, increase disease challenges, and influence the success of individual programs.
The ISRP offered nine recommendations to improve the LSRCP steelhead hatchery program. Among those are:
— Continue to monitor straying by LSRCP steelhead adults into Mid-Columbia River natural populations to determine if the recent reduced levels are sustained in the future.
— Use a structured decision process to evaluate the benefits and risks of the proposed future alternatives to address overshoot and straying for the Tucannon and Touchet river programs. Of the limited actions that can be taken, “the politically complex option of restoring reservoirs back to free-flowing reaches or providing adequate downriver passage in the lower Snake River for adult steelhead that overshoot and seek to return to their home river,” the ISRP said.
— Develop and implement sound study designs to assess the benefits and risks of supplementation programs in the Touchet, Tucannon, Imnaha, and East Fork Salmon rivers.
— Complete climate change assessments for the hatcheries that are at most risk.
— Develop a decision process that prioritizes infrastructure improvements, looking at an investment of $200 million ($400M in projects have already been proposed).
— Clearly articulate the basis and justification for adjusting SAR and SAS targets when smolt production levels are changed.
— The LSRCP and cooperators should develop a shared database for all data including Parental Based Tagging (PBT), develop systematic data quality assurance and analytical processes to maintain up-to-date estimates of key performance metrics, and work with the Coordinated Assessments Partnership (CAP) to complete entry of data and metadata into the Coordinated Assessments Data Exchange (CAX) database for key hatchery performance indicators.
For background, see:
— CBB, May 18, 2023, Science Review Of 50-Year-Old Lower Snake Compensation Program (Hatcheries) Shows Missed Return Goals For Spring/Summer Chinook, Science Review Of 50-Year-Old Lower Snake Compensation Program (Hatcheries) Shows Missed Return Goals For Spring/Summer Chinook – Columbia Basin Bulletin
— CBB, March 9, 2023, GUEST COLUMN: THE STATUS OF WILD SNAKE RIVER SALMON AND STEELHEAD; KEEPING THINGS IN PERSPECTIVE, HTTPS://CBBULLETIN.COM/GUEST-COLUMN-THE-STATUS-OF-WILD-SNAKE-RIVER-SALMON-AND-STEELHEAD-KEEPING-THINGS-IN-PERSPECTIVE/
— CBB, July 14, 2022, CURRENT RECOVERY PLAN NOT WORKING: TUCANNON RIVER SPRING CHINOOK IN BIG TROUBLE, OPTIONS EXPLORED, HTTPS://CBBULLETIN.COM/CURRENT-RECOVERY-PLAN-NOT-WORKING-TUCANNON-RIVER-SPRING-CHINOOK-IN-BIG-TROUBLE-OPTIONS-EXPLORED/
–CBB, Jan. 15, 2021, WASHINGTON STATE SALMON RECOVERY REPORT: MOST POPULATIONS NOT MAKING PROGRESS, SOME ON PATH TO EXTINCTION, https://columbiabasinbulletin.org/washington-state-salmon-recovery-report-most-populations-not-making-progress-some-on-path-to-extinction/