Status and Trends of Salmon and Steelhead in the Columbia River Basin
Number of Extant Populations
Current ESA Listing Status
Willamette/ Lower Columbia
Columbia River Chum
Lower Columbia River Spring/Fall Chinook
Upper Willamette River Chinook
Lower Columbia River Steelhead
Lower Columbia River Coho
Upper Willamette River Steelhead
Snake River Fall Chinook
Snake River Spring/Summer Chinook
Upper Columbia River Spring Chinook
Snake River Basin Steelhead
Middle Columbia River Steelhead
Upper Columbia River Steelhead
Snake River Sockeye
No Recovery Domain
Middle Columbia Spring Chinook
Okanogan River Sockeye
Lake Wenatchee Sockeye
Southwest Washington Steelhead
Upper Columbia River Summe Fall Chinook
Deschutes River Summer/Fall Chinook
Estimates of Adult Salmon and Steelhead at the Columbia River Mouth485,
From 2006 to 2010, the number of adult salmonids entering the Columbia River gradually increased until decreases were observed in 2011 and 2012. Increases were again observed in 2013 and 2014. The 2017 return was the lowest since 2007 (estimate does not include summer steelhead, as the information was not available).
Counts of Adult Salmon and Steelhead at Bonneville Dam60
Because Bonneville Dam is the lowermost hydrofacility on the Columbia River, counts of salmon and steelhead at the dam provide information important to the management of upriver stocks. Fish are counted at windows in ladders, either directly or by viewing video tape.
Counts at Bonneville Dam declined significantly from 2016 to 2017 with the total in 2017 being the lowest since 2007.
Counts of Adult Salmon and Steelhead at Priest Rapids Dam60
All returning Upper Columbia River salmonids, which include steelhead and endangered Upper Columbia River spring Chinook, must pass Priest Rapids Dam. In 2017, adult returns declined for a third consecutive year. Excluding 2014, the number of adults counted at the dam has been decreasing since 2012. The 2017 total return was the lowest since 2007.
Counts of Adult Salmon and Steelhead at Lower Granite Dam60
Endangered Snake River sockeye salmon must pass Lower Granite Dam, as must threatened Snake River spring/summer Chinook salmon and steelhead. In 2017, the number of salmon and steelhead returning to Lower Granite Dam was the lowest since 1999; however, sockeye and coho returns were greater than those observed in 2015 and 2016.
Hatchery Production of Salmon and Steelhead in the Columbia River Basin258
In 2017, 134.1 million juvenile salmonids were released into the Columba River Basin from state, tribal, federal, and private hatcheries. Hatchery programs are categorized based on their genetic broodstock management strategy, as either integrated (i.e., composite populations of natural- or hatchery-origin fish) or segregated (i.e., distinct population reproductively isolated from natural populations). The purpose of these programs is to either provide harvest opportunities, serve as a conservation measure, or both.
Columbia River Basin Salmon and Steelhead Harvest485,
Salmon and steelhead are harvested in the Columbia River Basin in commercial, sport, and treaty fisheries. Commercial fisheries are limited to the mainstem Columbia River below Bonneville Dam, whereas sport and treaty fisheries occur throughout the basin. Harvest levels are managed with allowable harvest linked directly to expected and observed run sizes. In recent years, the trend in overall harvest has been similar to the trend in run sizes.
Salmon and steelhead survival depends, in part, on the hydrology of the Columbia River Basin in conjunction with the operation of the hydrosystem. Juveniles, in particular, rely on flow to aid downstream migration; however, the annual discharge rate can fluctuate greatly. Flow is further regulated by the hydropower system. Dams have altered the seasonal flow of the basin to meet electricity, irrigation, flood control, navigation, recreation, and water supply demands. What was once a free-flowing river with a broad complex of habitats has been converted to a series of reservoirs.
Survival of juvenile salmonids may be directly affected by: 1) passage at dams, 2) increased time and energy needed for migration to the ocean, and 3) factors related to the changed river such as predation, disease, or thermal stress. Adult migration may be delayed or blocked by dams, and may also be affected by predation.
Actions intended to increase the survival of migrating juvenile salmonids include: 1) flow enhancement at critical times, 2) increase spill at dams, 3) placement of structures to increase passage efficiency, 4) transportation past dams and reservoirs, and 5) predation control measures. Actions to increase survival of migrating adults have been largely completed focusing on improving passage efficiency at dams. Predation control is an additional measure.
Survival of Adult Snake River Salmonids from Bonneville Dam to Lower Granite Dam
Straying Rates (%) of Adult Chinook Salmon (2001-08 Pooled) and Steelhead (2005-07 Pooled)
Steelhead (Wild and Hatchery)
Smolt-to-Adult Survival Rate (SAR; Lower Granite to Lower Granite) for Spring-Summer Chinook Salmon487
Note: 1. 2-6% SAR is goal of Northwest Power and Conservation Council 2. (C0) in 2001 assumed to equal (C1)
Smolt-to-Adult Survival Rate (SAR; Lower Granite to Lower Granite) for Wild Steelhead487
Note: 1. 2-6% SAR is goal of Northwest Power and Conservation Council 2. (C0) in 2001 assumed to equal (C1) 3. 2008 information available only for â??Overall"
Predation on Salmonids
Predation research and management in the Columbia River has focused on losses of juvenile salmonids to predacious fish (primarily northern pikeminnow) and birds (primarily Caspian terns and cormorants). Predation by non-native fish such as smallmouth bass, walleye, and channel catfish has also become a concern. Initial steps have been taken to evaluate and manage predation by these non-natives. Predation on adult salmonids and white sturgeon by sea lions below Bonneville Dam is an additional concern and actions to reduce this predation have been implemented.
The goal of the Northern Pikeminnow Management Program (NPMP) is to reduce predation on juvenile salmonids through sustained harvest of northern pikeminnow. The NPMP is based on research conducted from 1983-93 that indicated: 1) loss of juvenile salmonids to resident fish predators was significant, 2) northern pikeminnow were responsible for a majority of the losses, and 3) relatively large reductions in predation could be achieved through relatively low exploitation of northern pikeminnow. Since the NPMP was implemented in 1990, program fisheries have harvested more than 4.6 million northern pikeminnow. The 2017 harvest of fish >228 mm represents a decrease from the previous two years. The program reached its exploitation rate (10-20%) by achieving a rate of 17.4% for fish >250 mm.
Avian Predation on Juvenile Salmonids in the Lower Columbia River488
A 1997 study found that Caspian terns nesting on Rice Island were a significant predator of juvenile salmonids. Because they consumed more juvenile salmonids than any other prey, they were relocated closer to the ocean on East Sand Island. In 2017, 3,500 breeding pairs were observed, representing the smallest Caspian tern colony size observed since monitoring started in 2000. The number of terns nesting represents a 68% reduction from peak estimates in 2008. Researchers estimated that 5.2 million smolts were consumed by Caspian terns in 2015.
Double-crested cormorants are another common piscivorous water bird inhabiting the Columbia River Estuary. During 2014, East Sand Island supported 13,600 breeding pairs, approximately 26% more than the average number of double-crested cormorants that nested on East Sand Island from 1997 through 2013. Double-crested cormorants consumed approximately 16.3 million juvenile smolts in 2013.
Predation on Adult Salmonids by Sea Lions Near Bonneville Dam489
Adjusted Salmoind Consumtion Estimate
(Jan1 - May 31)
% of Run
In 2017, California and Steller sea lions ate an estimated 5,384 salmonids (adults and jacks). Researchers estimated that 4.7% of the adult salmon passage (January through May) was consumed by sea lions at Bonneville Dam.
Besides salmonids, sea lions also prey on white sturgeon and Pacific lamprey immediately below Bonneville Dam. During 2017, predation on white sturgeon was the lowest since monitoring began in 2005.
Sea lion predation on Pacific lamprey in 2017 represented a significant decrease compared to the previous year. The percent of total observed fish catch in 2016 was 1.7%.
Pacific Lamprey Background
Like salmon, Pacific lamprey are anadromous; however, their life-cycle is more complex than that of salmon. Juvenile lamprey remain burrowed in the substrate of streams for 4 to 6 years before emerging and migrating to the ocean in late-winter or early-spring. After 2 to 3 years in the ocean, adults return to streams from July to October and spawn the following spring.
Indigenous peoples from the Pacific Northwest have harvested adult lamprey for subsistence, religious, and medicinal purposes for many generations. Although historical population sizes of lamprey are unknown, adult Pacific lampreys are an important tribal subsistence food.
Pacific lamprey were likely distributed widely throughout the Columbia River Basin; however, counts at dams on the Columbia and Snake rivers indicate a severe decline in Pacific lamprey abundance. Annual counts at Bonneville Dam prior to 1970 often exceeded 250,000 fish. Counts at most dams have decreased dramatically in recent years.
In 2017, counts at all of the hydrofacilities reflected an increase in comparison to previous years with counts at five locations being the highest ever recorded. Dam counts are used to index the relative abundance of Pacific lamprey, but these counts are of limited use in estimating actual abundance. Many adult lamprey pass at night when counting is not conducted. In addition, numerous routes are available for lamprey to pass dams without being detected. Research to develop more accurate counting methods is underway.
Although returns increased, passage obstructions, degraded habitat, and impaired water quality are all factors that continue to affect population growth. Predation by exotic predators may also decrease lamprey productivity.
Recent efforts have begun to address limiting factors and threats, especially passage of adults at mainstem dams. Structures designed to improve the collection and passage of lamprey have been installed at several of the dams. Gratings and screens have been replaced to enhance passage. In addition, sharp corners in and around fish ladders are being rounded to further improve adult passage. Velocity-reducing structures are being evaluated. Adult and juvenile lamprey passage needs will continue to be evaluated at each dam.
Trends at Columbia River Hydroelectric Facilities60
Trends of Adult Pacific Lamprey Counts at Columbia River Hydroelectric Facilities (2017)
The Dalles Dam
John Day Dam
Priest Rapids Dam
Rock Island Dam
Rocky Reach Dam
Ice Harbor Dam
Lower Monumental Dam
Little Goose Dam
Lower Granite Dam
Genetic population structure for Pacific lamprey is currently unknown in the Columbia River Basin,
thus, specific populations or management groups have not been established this time.
In addition, little is known about adult returns to specific waters.
Counts of Adult Pacific Lamprey at Bonneville, McNary and Lower Granite Dams60
Dam counts are used to index the relative abundance of Pacific lamprey, but these counts are of limited use in estimating actual abundance. Many adult lamprey pass at night when counting is not conducted. In addition, numerous routes are available for lamprey to pass dams without being detected. Research to develop more accurate counting methods is underway.
Resident fish Substitution
Northwest Power and Conservation Council's Anadromous Fish Mitigation in Blocked Areas Policy 265
Resident fish populations throughout the Columbia River Basin have been affected by the construction and operation of the hydropower system. Dams altered natural river flows, inundated spawning and rearing areas, and blocked natural migration patterns. Historically, more than two million salmon and steelhead spawned annually in the upper Columbia River and Snake River basins.
Mitigation for the annual losses of anadromous fish in these blocked areas is partially achieved through the release of hatchery-produced fish such as kokanee, rainbow trout, brook trout, and Lahontan cutthroat trout as well as habitat projects to benefit resident fish populations. These efforts are essential for providing tribal subsistence and public recreation fisheries, opportunities that were lost due the lack of passage for anadromous fish to reach historic spawning areas.
Columbia River Basin Resident Fish Substitution Releases 490,