Condit Dam was removed from river kilometer (rkm) 5.3 of the White Salmon River, Washington, in 2011 and 2012 after blocking upstream passage of anadromous fish for nearly 100 years. The dam removal opened habitat upstream and improved habitat downstream with addition of cobble and gravel to a reach depauperate of spawning and rearing habitat. We assessed juvenile anadromous salmonid abundance and distribution in the subbasin from 2016 through 2021 to evaluate the efficacy of natural recolonization. We sampled for outmigrant smolts and other life-history stages at a rotary screw trap at rkm 2.3 and for juvenile abundance at sites in Buck and Rattlesnake Creeks, two primary tributaries upstream from the former dam location.
We estimated smolt abundance of steelhead (
Other species and life stages also were captured in the screw trap. Steelhead and coho salmon fry and parr, and Chinook salmon (
We confirmed the presence of juvenile steelhead (through smolt origin data) and coho salmon in Mill, Buck, and Rattlesnake Creeks, which are all upstream from the former site of Condit Dam. Juvenile salmonid abundance sampling at a site in Buck Creek during 2016–20 indicated the presence of juvenile coho salmon in all years except 2020. Total salmonid abundance (steelhead and coho salmon combined) at the Buck Creek site each year exceeded abundance in sampling prior to dam removal in 2009 and 2010. Juvenile salmonid abundance sampling in Rattlesnake Creek during 2016–20 indicated the presence of juvenile coho salmon in 2017, 2018, and 2019. Total juvenile salmonid abundance at the Rattlesnake Creek site was highly variable, sometimes exceeding and sometimes less than abundance prior to dam removal during 2001–05. During the period covered by this report, adult salmonid returns to the Columbia River were decreasing, largely because of marine survival. The extent to which this basin-wide decrease affected adult returns and juvenile populations in the White Salmon River subbasin is not known.
Despite a period of poor marine survival, PIT-tagged smolt and juvenile steelhead and coho salmon from the screw trap and tributaries returned to Bonneville Dam. Smolt-to-adult return rates from the screw trap to Bonneville Dam were similar to those in other nearby rivers during this period. However, data are still incomplete for some years and sample sizes were low. Future tagging and monitoring would be beneficial to track this valuable metric.
Genetic samples from steelhead smolt and parr collected at the screw trap and some main-stem electrofishing during 2016 were analyzed for Genetic Stock Identification (GSI) by CRITFC. Preliminary data showed that White Salmon River fish were the most common at about 42 percent, with 19 percent typing to Hood River, Oregon stock, and about 26 percent typing to Skamania stock, a common hatchery stock in the area. Winter and summer runs were represented in the samples.
Juvenile salmonid sampling in the White Salmon River, Washington, following removal of Condit Dam, demonstrated that anadromous salmonids are using newly opened habitat upstream from the former dam site and improved lower river habitat. Steelhead and coho salmon smolts are being produced upstream from the former dam site, and some have returned to Bonneville Dam as adults. Chinook salmon spawning upstream from our smolt trap site are producing fry. These results are encouraging for success of the strictly natural recolonization strategy. However, declines in anadromous runs to the larger Columbia River Basin also likely have affected the White Salmon runs and our data may not reflect full capacity of the White Salmon River subbasin juvenile production. Continued abundance, distribution, and GSI monitoring will help to track the evolution of anadromous fish in the White Salmon River under a natural recolonization strategy.
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Funding for this project during 2018–21 was from the Pacific Coastal Salmon Recovery Fund and for years 2016 and 2017 was from the Washington State Salmon Recovery Funding Board and Clark-Skamania Flyfishers. We thank Margaret Neuman, with Mid-Columbia Fisheries Enhancement Group, and Joe Zendt, with Yakama Nation, for support and efforts to acquire and administer these funds. Seth Raehsler, with the Mid-Columbia Fisheries Enhancement Group, provided field assistance. Jacob Anderson, with Klickitat County, provided support and communication assistance during the proposal process. Thomas Buehrens and Bryce Glaser, of Washington Department of Fish and Wildlife, provided support and feedback for our proposal and assistance with permitting. Additionally, they provided a tablet field computer for use at our smolt trap. Ben Warren and Daniel Warren, of the Washington Department of Fish and Wildlife, provided instruction and support in using the tablet computer. The Washington Department of Fish and Wildlife also aged scales collected at the screw trap during 2021. Jorge Alcala, Michael Clark, Mark Doulos, Ken Lujan, and Larry Zeigenfuss, of the U.S. Fish and Wildlife Service, provided us property access and help with screw-trap deployment and removal. Joe Zendt and Mike Babcock, with the Yakama Nation Fisheries Program, provided us with some of the passive integrated transponder tags used. Hal Hansel, Jessica Hudec, Gavin Plumb, Emma Tiffan, and Ben Weiland all provided volunteer assistance. We thank the landowners who provided property access, including PacificCorp, the U.S. Forest Service, the Washington State Department of Natural Resources, David Crumpacker, Susan and Rainer Hummel, Steve Stampfli, and Terie Tietjen. We also thank the technical and citizens committees of the Klickitat Lead Entity and the Lower Columbia Fish Recovery Board, as well as the board members, for their support. Nico Romero, of Yakama Nation, and Dalton Lebeda, of U.S. Geological Survey (USGS), provided helpful reviews of this report.
We thank our fellow USGS employees Shane Amen, Morgan Andrews, Pat Connolly, Sam Doak, Nicole Eller, Phil Haner, Riley Haner, Will Hurst, Brad Liedtke, Marty Liedtke, Rachel Ohnemus, Jonathan Schafer, Dennis Sitherwood, Ken Tiffan, Ryan Tomka, Andy Wells, and Lisa Weiland for help in the field and office. We also thank the USGS Student Interns in Support of Native American Relations program and the Cooperative Summer Field Training program, in partnership with the National Association of Geoscience Teachers, which both provided support for seasonal staff.
Multiply | By | To obtain |
Length | ||
---|---|---|
centimeter (cm) | 0.3937 | inch (in.) |
millimeter (mm) | 0.03937 | inch (in.) |
meter (m) | 3.281 | foot (ft) |
kilometer (km) | 0.6214 | mile (mi) |
kilometer (km) | 0.5400 | mile, nautical (nmi) |
meter (m) | 1.094 | yard (yd) |
Area | ||
square kilometer (km2) | 0.3861 | square mile (mi2) |
Volume | ||
liter (L) | 0.2642 | gallon (gal) |
cubic meter (m3) | 35.31 | cubic foot (ft3) |
Flow rate | ||
cubic meter per second (m3/s) | 35.31 | cubic foot per second (ft2/s) |
Mass | ||
milligram (mg) | 0.00003527 | ounce, avoirdupois (oz) |
gram (g) | 0.03527 | ounce, avoirdupois (oz) |
Temperature in degrees Celsius (°C) may be converted to degrees Fahrenheit (°F) as follows:
°F = (1.8 × °C) + 32.
Vertical coordinate information is referenced to North American Vertical Datum of 1988 (NAVD 88).
Altitude, as used in this report, refers to distance above the vertical datum.
Concentrations of chemical constituents in water are given in milligrams per liter (mg/L).
confidence interval
Columbia River Intertribal Fish Commission
Distinct Population Segment
Endangered Species Act
Evolutionary Significant Unit
fork length
Fish Passage Center
Genetic Stock Identification
Juvenile Migrant Exchange
kilohertz
Lower Columbia Fish Recovery Board
Lower Columbia River
large woody debris
Middle Columbia River
tricaine methanesulfonate
National Marine Fisheries Service
Northwest Power and Conservation Council
passive integrated transponder
PIT Tag Information System
river kilometer
smolt-to-adult return
standard error
U.S. Fish and Wildlife Service
U.S. Geological Survey
viable salmonid population
Washington Department of Fish and Wildlife
White Salmon Technical Work Group
Yakama Nation
Condit Dam, on Washington’s White Salmon River, blocked upstream fish passage for nearly 100 years. The dam, at river kilometer (rkm) 5.3 (
The White Salmon River watershed is in the Lower Columbia River (LCR) Evolutionary Significant Unit (ESU) salmon recovery domain and the Middle Columbia River (MCR) Distinct Population Segment (DPS) steelhead recovery domain (
Tagging of
The removal of Condit Dam reopened main-stem and tributary habitat for anadromous fish. Condit Dam blocked 27 kilometers (km) of potential coho salmon habitat, 15 km of potential spring Chinook salmon habitat, 7 km of potential fall chinook salmon habitat, and 50 km of potential steelhead habitat (Northwest Power and Conservation Council [
Numerous Federal and State plans call for monitoring of listed stocks in ESUs and their subunits to gage viable salmonid population (VSP) status and trends (
Prior to removal of Condit Dam, the White Salmon Technical Work Group (WSTWG) formed to develop a fish-recolonization strategy. The group included representatives of U.S. Geological Survey (USGS), U.S. Fish and Wildlife Service (USFWS), U.S. Forest Service, Yakama Nation (YN), Washington Department of Fish and Wildlife (WDFW), NMFS, and PacifiCorp. The WSTWG recommended natural recolonization for each species with 5 years of post-dam removal monitoring (
The ESA Recovery Plan for the White Salmon River Watershed (
Dam removals have increased nationwide (
The removal of Condit Dam provides an opportunity to evaluate the efficacy of dam removal and natural recolonization as a restoration strategy and to contribute to the science of dam removals. Condit Dam is a relatively unique case to date (December 2022) because it was a high dam (38 meters [m]), and a large amount of sediment was released (1.8 million cubic meters [m3];
Several pre-dam removal studies were done in the White Salmon River upstream and downstream from Condit Dam. In Buck and Rattlesnake Creeks, USGS assessed abundance of
In 2008, biologists from USFWS captured adult fall Chinook salmon in the lower White Salmon River and released some upstream from Condit Dam to assess capture methods and potential spawning success (
Limited monitoring on the White Salmon River had been done since the removal of Condit Dam, but the members of the WSTWG continued to coordinate (
Steelhead and coho salmon spawning survey limitations and difficulties (prolonged spawning period, high flows, turbidity, iteroparity) are exacerbated by the confined and high-gradient character of the main-stem White Salmon River. Steelhead spawning surveys in tributaries are providing spatial distribution data and an index of abundance, but not a subbasin adult population estimate. Additionally, it was unknown if steelhead and coho spawning in tributaries were producing viable anadromous offspring. Because of the challenges of surveying adult steelhead and coho salmon, a monitoring approach that includes smolt and juvenile abundance and life-history data was needed. The LCFRB’s Research Monitoring and Evaluation Program for Lower Columbia Salmon and Steelhead (
During 2016, USGS began monitoring of juvenile salmonids in the White Salmon River post-dam removal and this report conveys findings from 2016 to 2021. The goals of our work were to assess (1) smolt production from anadromous spawning upstream from rkm 2.3; (2) juvenile salmonid distribution throughout the watershed; and (3) juvenile salmonid abundance in select reaches of Rattlesnake and Buck Creeks, two primary tributaries of the White Salmon River. We assessed smolt production with a rotary screw trap at rkm 2.3, which is a new location for a rotary screw trap in the White Salmon River (the site used from 2006 through 2009 at rkm 1.5 is no longer viable because of sediment deposition, a very dynamic channel, and lack of access). We assessed juvenile salmonid distribution and abundance by backpack electrofishing. Because we used PIT tags for mark-recapture estimates, future recaptures or detections of these fish will contribute to knowledge of life-history diversity of naturally produced salmonids in the White Salmon River. These data are (1) helpful in evaluating (a) the efficacy of dam removal as a restoration and recovery strategy, and (b) the efficacy of a natural recolonization strategy for anadromous salmonids; and (2) in informing managers of the status of salmonid stocks listed as threatened under the Endangered Species Act.
The White Salmon River watershed encompasses about 1,000 square kilometers (km2) of Klickitat, Yakima, and Skamania Counties in south-central Washington (
White Salmon River watershed accessible to anadromous salmonids and the locations of rotary screw trapping and electrofishing surveys, Washington, 2018–21. The former location of Condit Dam, which was breached in 2011, also is shown. OR, Oregon; WA, Washington.
Figure 1. Schematic showing the White Salmon River watershed accessible to anadromous salmonids and the locations of rotary screw trapping and electrofishing surveys, Washington, 2018–21
Water quantity and quality in the White Salmon River are favorable for salmonids (
The main-stem White Salmon River has many waterfalls. The largest is Big Brother Falls (about 7.3 m high) at rkm 26, which is likely the upstream extent of anadromous distribution. BZ Falls (about 4.5 m high) is at rkm 20 and is likely a barrier to salmon, although steelhead can most likely ascend it (
The characteristics of the lower 8.0 km of the main-stem White Salmon River have rapidly changed since the breaching of Condit Dam at rkm 5.3. An estimated 1.8 million m3 of reservoir sediments were impounded (
Four tributaries to the White Salmon River in our study area were accessible to anadromous fish. Mill, Buck, Spring, and Rattlesnake Creeks all enter the White Salmon River between the former dam site and Husum Falls. We sampled fish in Mill, Buck, and Rattlesnake Creeks, but did not have permission to access Spring Creek.
Mill Creek flows to the White Salmon River from the west at rkm 6.4 (
Buck Creek flows into the White Salmon River from the northwest at rkm 7.5 (
Rattlesnake Creek flows to the White Salmon River from the east at rkm 13.8 (
Discharge in Rattlesnake Creek is extremely low during summer (
We operated a 1.5-m-diameter rotary screw trap (E.G. Solutions, Corvallis, Oregon) at rkm 2.3 of the White Salmon River (
The screw trap was operated continuously during trapping periods each year; occasional outages occurred because of high water or debris. Each day, debris was removed from the live box, and captured fish were netted into buckets and transported to shore. Captured fish were held in buckets or coolers with ambient aerated stream water. Fish were anesthetized with 50 milligrams per liter of tricaine methanesulfonate (MS-222), identified to species, measured for fork length (FL) to the nearest millimeter (mm), and weighed to the nearest 0.1 gram (g). All salmonids captured were classified to life stage as fry (<46 mm FL), parr, transitional, or smolt. Salmonids were checked for marks to determine if they were recaptures. Fish 70 mm or greater FL were scanned for PIT tags and PIT-tagged (12-mm, 134.2-kilohertz [kHz] tags; Biomark, Boise, Idaho) if not previously tagged. Tags were injected into the peritoneal cavity following methods outlined by
Capture efficiency, defined as the percentage of fish passing the trap that are captured (
is the estimate of unmarked fish migrating during sample period,
is the number of unmarked fish captured during sample period,
is the number of fish marked and released during sample period,
is the number of marked fish captured during sample period, and
is the variance.
All screw-trap data were electronically entered on a field computer provided by WDFW and configured to accept data into their Juvenile Migrant Exchange (JMX) database. All screw-trap data were entered into the JMX database. All mark and recapture data from PIT-tagged fish were provided to the PIT Tag Information System (PTAGIS) database administered by the Pacific States Marine Fisheries Commission. Estimates of smolt migrants will be provided to the Coordinated Assessments Database.
We used backpack electrofishing to assess juvenile salmonid abundance at a site in the most downstream reach of Rattlesnake Creek (starting at rkm 0.2; site length, 245 m) and a site in reach 2 of Buck Creek (starting at rkm 2.0; site length, 222 m) during summer 2018, 2019, and 2020 (
We estimated abundance of fish using the mark-recapture methods outlined in
Once the nets were secured to prevent immigration or emigration, we electrofished the section in an upstream pass to collect and mark fish. Two or three crew members dip-netted fish, which were immediately placed in buckets or coolers with ambient, aerated stream water. Captured fish were anesthetized with the lightest possible dose of MS-222, measured for FL to the nearest mm, weighed to the nearest 0.1 g, and marked. Salmonids with a 70-mm or greater FL were PIT-tagged with a 12-mm tag, and salmonids with a 60–69-mm FL were PIT-tagged with a 9-mm tag (both tags were 134.2 kHz). Salmonids less than 60 mm in size were given a caudal fin clip. Fish were released as close as possible to their point of capture. Block nets were left overnight, and the following day we repeated the electrofishing effort as a recapture pass. During fish workup for the recapture pass, all fish were checked for a PIT tag or fin clip mark. Fin clips from fish too small to tag were archived for potential genetic analysis, and genetic clips were taken from at least 20 larger fish as well.
Mark-recapture estimates followed methods outlined in
is the population estimate,
is the number of fish marked during the mark sample effort,
is the total number of fish captured in the recapture sample effort,
is the number of marked fish captured in the recapture sample effort, and
is the variance.
To quantify habitat area, we measured width and depth at 10 or more transects, equally spaced through the mark-recapture section. With these data, we calculated the study section length and area to estimate fish-per-meter and fish-per-square meter.
During all sample years (2016–19 and 2021), we captured steelhead, coho salmon, and Chinook salmon in the screw trap (
Table 1. Number of steelhead, Chinook salmon, and coho salmon, by life stage, captured, tagged with passive integrated transponder tags, and sampled for genetic material at the screw trap at river kilometer 2.3, White Salmon River, Washington, 2016–21
[Fry were 45 millimeters in fork length or less.
Life stage | Steelhead | Chinook salmon | Coho salmon | ||||||||
N | PIT- |
Gen. | N | PIT- |
Gen. | N | PIT- |
Gen. | |||
2016 | |||||||||||
---|---|---|---|---|---|---|---|---|---|---|---|
Fry | 9 | NA | 0 | 4 | NA | 2 | 19 | NA | 17 | ||
Parr | 23 | 20 | 21 | 0 | 0 | 0 | 2 | 0 | 2 | ||
Smolt | 153 | 150 | 149 | 0 | 0 | 0 | 82 | 79 | 79 | ||
2017 | |||||||||||
Fry | 14 | NA | 1 | 203 | 0 | 124 | 55 | NA | 0 | ||
Parr | 61 | 57 | 59 | 19 | 3 | 16 | 25 | 12 | 0 | ||
Smolt | 40 | 39 | 40 | 1 | 1 | 1 | 13 | 11 | 2 | ||
2018 | |||||||||||
Fry | 23 | NA | 0 | 239 | NA | 132 | 58 | NA | 19 | ||
Parr | 54 | 46 | 37 | 3 | 0 | 3 | 4 | 0 | 4 | ||
Smolt | 404 | 403 | 278 | 2 | 2 | 3 | 122 | 117 | 109 | ||
2019 | |||||||||||
Fry | 12 | NA | 2 | 147 | NA | 101 | 80 | NA | 12 | ||
Parr | 66 | 52 | 46 | 11 | 0 | 11 | 8 | 4 | 8 | ||
Smolt | 328 | 321 | 267 | 1 | 0 | 1 | 196 | 191 | 151 | ||
12020 | |||||||||||
Not fished | |||||||||||
2021 | |||||||||||
Fry | 2 | NA | 1 | 14 | NA | 13 | 1 | NA | 1 | ||
Parr | 40 | 36 | 39 | 1 | 1 | 1 | 0 | -- | -- | ||
Smolt | 308 | 301 | 280 | 0 | 0 | 0 | 2 | 2 | 2 | ||
The trap was not fished in 2020 because of the COVID-19 pandemic.
Table
[Because of prolonged high water and missed trapping days during 2017, we could not generate estimates. We did not fish the trap during 2020 because of the onset of the COVID-19 pandemic.
Species | Number |
Number |
Number |
Estimate | SE | 95-percent CI |
2016 | ||||||
---|---|---|---|---|---|---|
Steelhead | 153 | 150 | 5 | 3,851 | 1,454 | 1,001–6,700 |
Coho | 82 | 79 | 5 | 1,093 | 412 | 286–1,900 |
Age-0 Chinook | 4 | 0 | NA | NA | NA | NA |
2017 | ||||||
Steelhead | 40 | 39 | 1 | NA | NA | NA |
Coho | 13 | 12 | 0 | NA | NA | NA |
Age-0 Chinook | 222 | 192 | 4 | NA | NA | NA |
2018 | ||||||
Steelhead | 420 | 403 | 28 | 5,851 | 1,064 | 3,765–7,937 |
Coho | 127 | 118 | 12 | 1,163 | 307 | 559–1,766 |
Age-0 Chinook | 242 | 168 | 1 | NA | NA | NA |
2019 | ||||||
Steelhead | 1338 | 321 | 26 | 4,031 | 758 | 2,546–5,516 |
Coho | 1198 | 187 | 20 | 1,773 | 375 | 1,038–2,507 |
Age-0 Chinook | 159 | 79 | 0 | NA | NA | NA |
2020 | ||||||
Not fished | -- | -- | -- | -- | -- | -- |
2021 | ||||||
Steelhead | 308 | 301 | 23 | 3,876 | 772 | 2,362–5,389 |
Coho | 2 | 2 | 0 | NA | NA | NA |
Age-0 Chinook | 14 | 0 | NA | NA | NA | NA |
Includes estimated catch for missed sample days.
During 2018, the screw trap was fished continuously from March 27 to June 15, except for 4 days because of high water or thunderstorms (sample days = 76). Flow was generally moderate. Recapture rates during 2018 were 6.9 percent for steelhead smolts and 10.4 percent for coho salmon smolts. Steelhead and coho salmon smolt estimates were 5,841 and 1,163, respectively (
Steelhead (
Figure 2. Bar graph showing steelhead and coho salmon smolt estimates at a screw trap operated at river kilometer 2.3 of the White Salmon River, Washington, 2009–10 and 2016–21
During 2019, the screw trap was fished continuously from March 25 to June 12, except for 4 days because of high water or thunderstorms (sample days = 75). Flow was moderate to low. Recapture rates during 2019 were 8.1 percent for steelhead smolts and 10.7 percent for coho salmon smolts. Steelhead and coho salmon smolt estimates were 4,031 and 1,773, respectively (
During 2021, the screw trap was fished continuously from March 29 to June 8, with moderate to low flow. We captured steelhead fry, parr, and smolt (
Screw trapping provided timing data of fish movement in the lower river. Age-0 coho and Chinook salmon typically were present throughout the sampling period. Age-0 steelhead were present through the sampling period in 2018 and 2019; during 2016, first capture was on May 7, and during 2017, first capture was on May 17. We were not able to determine any peak of age-0 abundance owing to the capture of age-0 fish being highly dependent upon debris load and operation of the cleaning drum (age-0 fish easily get rotated out). Each year, steelhead parr were present throughout the season. The date for 50-percent capture of steelhead parr varied from April 25 to May 18; however, parr capture rate was relatively steady throughout the sample periods without a pronounced peak. The extent of parr movement past our spring monitoring period is unknown. First capture of steelhead smolts occurred during the last week of March (except in 2017, when sampling started later because of high water) and last capture generally occurred around the second week of June (except in 2016, when sampling ended early because of damage to the trap). The date range of 50-percent capture of steelhead smolts was from May 1 to 10. First capture of coho salmon smolts ranged from March 25 to April 20 and last capture occurred during the first or second week of June (except in 2016). The date range of 50-percent capture of coho salmon smolts was from May 7 to May 11.
During our screw-trap sampling efforts, we periodically captured steelhead smolts previously tagged in the Hood River, Oregon as parr or smolts. Two steelhead smolts captured in the screw trap in 2018 were PIT-tagged as parr in the Hood River during 2017, one as a 104-mm parr at the main-stem screw trap on May 25, 2017, and the other as a 139-mm parr in the East Fork Hood River screw trap on September 27, 2017. Neither of these fish were detected at the PIT-tag interrogation site at the mouth of the Hood River, so we do not know when they migrated from the Hood River to the White Salmon. During 2019, two steelhead smolts captured at the White Salmon screw trap were originally PIT-tagged in the Hood River during 2018, one at the East Fork Hood River screw trap on May 23, 2018 (FL = 153 mm), and the other at the main-stem screw trap on September 14, 2018 (FL = 170 mm). The fish from the East Fork Hood River trap was detected at the mouth of the Hood River PIT-tag detection system on November 5, 2018.
Other fish of interest captured during screw-trap sample efforts include lamprey and bull trout. We captured 44 lamprey in the screw trap during 2018, 31 lamprey during 2019, and 11 lamprey during 2021. Genetic samples were collected from lamprey for years 2016–21. We captured three bull trout in the screw trap, one on June 5, 2018 (FL = 193), one on June 10, 2019 (FL = 153 mm) and one on June 4, 2021 (FL = 177 mm). All three showed smolt characteristics, had genetic samples taken, and were PIT-tagged. The bull trout captured on June 5, 2018 was detected at Bonneville Dam Corner Collector on June 7, 2018, indicating likely anadromy.
During 2016–20, we estimated abundance of age-0 and age-1 or older
Table 3. Abundance estimates and standard error, fish per meter, and fish per meter squared of steelhead/rainbow trout and coho salmon at an abundance electrofishing site in Rattlesnake Creek, Washington, 2016–20
[No coho salmon were captured during 2016 or 2020.
Species | Age |
Number |
Number |
Number |
Abundance |
SE | Fish |
Fish per |
2016 | ||||||||
---|---|---|---|---|---|---|---|---|
Sth/Rbt | 0 | 125 | 149 | 25 | 727 | 113.3 | 3.6 | 0.46 |
Sth/Rbt | ≥1 | 7 | 3 | 1 | 16 | 5.7 | 0.1 | 0.01 |
2017 | ||||||||
Sth/Rbt | 0 | 165 | 157 | 49 | 525 | 50.8 | 2.4 | 0.35 |
Sth/Rbt | ≥1 | 41 | 34 | 20 | 70 | 6.7 | 0.3 | 0.05 |
Coho | 0 | 45 | 39 | 15 | 115 | 17.4 | 0.5 | 0.08 |
2018 | ||||||||
Sth/Rbt | 0 | 118 | 111 | 44 | 296 | 26.6 | 1.2 | 0.18 |
Sth/Rbt | ≥1 | 32 | 22 | 12 | 58 | 8.0 | 0.2 | 0.04 |
Coho | 0 | 84 | 102 | 39 | 219 | 19.5 | 0.9 | 0.13 |
2019 | ||||||||
Sth/Rbt | 0 | 85 | 70 | 36 | 165 | 14.0 | 0.7 | 0.11 |
Sth/Rbt | ≥1 | 41 | 40 | 23 | 72 | 6.0 | 0.3 | 0.05 |
Coho | 0 | 25 | 12 | 9 | 34 | 3.8 | 0.1 | 0.02 |
2020 | ||||||||
Sth/Rbt | 0 | 129 | 138 | 55 | 323 | 24.9 | 1.3 | 0.20 |
Sth/Rbt | ≥1 | 15 | 19 | 9 | 32 | 4.2 | 0.1 | 0.02 |
Abundance estimates of steelhead/rainbow trout (
Figure 3. Bar graph showing abundance estimates of steelhead/rainbow trout and coho salmon in a sample section in the lower kilometer of Rattlesnake Creek, Washington, 2001–05 and 2016–20
Table 4. Abundance estimates and standard error, fish per meter, and fish per meter squared of steelhead/rainbow trout and coho salmon at an abundance electrofishing site in Buck Creek, Washington, 2016–20
[No coho salmon were captured in 2020.
Species | Age |
Number |
Number |
Number |
Abundance |
SE | Fish |
Fish per |
2016 | ||||||||
---|---|---|---|---|---|---|---|---|
Sth/Rbt | 0 | 113 | 128 | 25 | 566 | 85.5 | 3.0 | 0.37 |
Sth/Rbt | ≥1 | 33 | 31 | 9 | 109 | 22.9 | 0.6 | 0.07 |
Coho | 0 | 35 | 29 | 10 | 98 | 18.8 | 0.5 | 0.06 |
2017 | ||||||||
Sth/Rbt | 0 | 61 | 54 | 11 | 284 | 62.6 | 1.2 | 0.20 |
Sth/Rbt | ≥1 | 92 | 106 | 37 | 262 | 25.9 | 1.1 | 0.18 |
Coho | 0 | 75 | 62 | 27 | 171 | 18.8 | 0.7 | 0.12 |
2018 | ||||||||
Sth/Rbt | 0 | 183 | 193 | 55 | 637 | 59.4 | 2.9 | 0.45 |
Sth/Rbt | ≥1 | 67 | 61 | 35 | 117 | 8.6 | 0.5 | 0.08 |
Coho | 0 | 52 | 56 | 23 | 126 | 14.2 | 0.6 | 0.09 |
2019 | ||||||||
Sth/Rbt | 0 | 185 | 178 | 74 | 444 | 30.0 | 2.0 | 0.34 |
Sth/Rbt | ≥1 | 103 | 89 | 49 | 187 | 12.6 | 0.8 | 0.14 |
Coho | 0 | 2 | 1 | 1 | -- | -- | -- | -- |
2020 | ||||||||
Sth/Rbt | 0 | 244 | 224 | 89 | 612 | 39.6 | 2.7 | 0.42 |
Sth/Rbt | ≥1 | 69 | 60 | 23 | 178 | 22.5 | 0.8 | 0.12 |
Abundance estimates of steelhead/rainbow trout (
Figure 4. Bar graph showing abundance estimates of steelhead/rainbow trout and coho salmon in a sample section at river kilometer 2 of Buck Creek, Washington, 2009–10 and 2016–20
During 2018, we estimated abundance of age-0 and age-1 and older salmonids in sections of Rattlesnake and Buck Creeks (
During 2019, we estimated abundance of age-0 and age-1 and older salmonids in sections of Rattlesnake and Buck Creeks (
During 2020, we estimated abundance of age-0 and age-1 and older salmonids in sections of Rattlesnake and Buck Creeks (
Salmonid abundance sampling done in Rattlesnake and Buck Creeks prior to dam removal provides a comparison with abundance found in our post-dam removal sampling. Juvenile salmonid abundance in our Rattlesnake Creek sample site during 2016–18 (range = 2.3–3.7 fish/m) was within the range measured in pre-dam removal surveys during 2001–05 (
Steelhead and coho salmon PIT-tagged as smolts and parr at the screw trap have been detected as juveniles at Bonneville Dam and other downstream detection sites. Median travel times to Bonneville Dam for coho salmon smolts PIT-tagged at the screw trap were 2 days in 2016 (n = 16; range 1–34), 2.5 days in 2018 (n = 14; range = 1–49), and 4.5 days in 2019 (n = 36; range = 1–36). Median travel times to Bonneville Dam for steelhead smolts PIT-tagged at the screw trap were 3 days in 2016 (n = 26; range = 1–49), 2 days in 2018 (n = 56; range = 1–27), 3 days in 2019 (n = 54; range = 1–42), and 2 days in 2021 (n = 62; range = 1–34). Steelhead and coho salmon PIT-tagged as parr in tributaries have subsequently also been detected at Bonneville Dam or other downstream detection sites, confirming anadromous life histories originating from the tributaries.
Additional detections of PIT-tagged juvenile steelhead have occurred aside from the expected smolt detections at Bonneville Dam and the estuary trawl. Three steelhead that were PIT tagged as age-0 (FLs = 62, 67, 71 mm) fish in Rattlesnake Creek during summer 2017 were detected at the PIT-tag interrogation system at the mouth of the Hood River (PTAGIS site code = HRM) during February 2018. Several juvenile steelhead PIT-tagged in 2019 in the White Salmon subbasin also were detected at HRM. One steelhead PIT-tagged as a parr (FL = 118 mm) at the White Salmon screw trap on May 5, 2019 was detected at HRM on May 31, 2019; another steelhead PIT-tagged in Rattlesnake Creek as an age-0 (FL = 61 mm) on September 4, 2019, was detected at HRM on September 13, 2020; and a third steelhead PIT-tagged in Buck Creek on August 27, 2019 as an age-0 (FL = 60 mm) was detected at HRM on January 15, 2021. An age-0 steelhead PIT-tagged in Rattlesnake Creek (FL = 67 mm) on September 3, 2020 was detected at HRM on September 1, 2021. A steelhead parr PIT-tagged at the White Salmon River screw trap in 2018 (FL = 104 mm) was detected in the fish ladder at Spring Creek National Fish Hatchery on September 22, 2018. A steelhead smolt PIT-tagged at the White Salmon River screw trap in 2018 (FL = 159 mm) was detected moving upstream through the Washington shore ladder at Bonneville Dam on August 29, 2018, possibly an early maturing adult.
Steelhead and coho salmon PIT-tagged at the White Salmon River screw trap have returned as adults to Bonneville Dam on the Columbia River (rkm 233). Four steelhead and two coho salmon smolts PIT-tagged in 2016 at the screw trap (150 steelhead and 79 coho salmon smolts tagged at the screw trap) have returned as adults to Bonneville Dam (
Smolt-to-adult return (SAR) rate estimates, for steelhead and coho salmon, from the screw trap to Bonneville Dam, ranged from 1.2 to 2.7 percent for the years in which we can estimate them (
Table 5. Smolt-to-adult return rate and ocean age of steelhead passive integrated transponder-tagged as smolts at the White Salmon River screw trap that returned as adults to Bonneville Dam, Washington, 2016–21
[
Year | Smolts tagged | Ocean age | Total adults | SAR | CV | 95% CI | ||
1 Ocean | 2 Ocean | 3 Ocean | ||||||
2016 | 150 | 1 | 3 | 0 | 4 | 2.7 | 49.3 | 0.1–5.2 |
12017 | 39 | 0 | 0 | 0 | 0 | NE | -- | -- |
2018 | 403 | 1 | 4 | 0 | 5 | 1.2 | 44.4 | 0.1–2.3 |
2019 | 321 | 0 | 1 | 0 | 1 | 0.3 | 99.9 | 0–0.9 |
22020 | 0 | -- | -- | -- | -- | -- | -- | -- |
2021 | 301 | 0 | -- | -- | -- | -- | -- | -- |
High water and missed trap periods resulted in few fish tagged at the screw trap in 2017.
Trap not fished in 2020 because of the COVID-19 pandemic.
Table 6. Smolt-to-adult return rate and ocean age of coho salmon passive integrated transponder-tagged as smolts at the White Salmon River screw trap that returned as adults to Bonneville Dam, Washington, 2016–21
[
Year | Smolts |
Adults |
SAR | CV | 95% CI |
2016 | 79 | 2 | 2.5 | 69.8 | 0–6.0 |
12017 | 11 | 0 | NE | -- | -- |
2018 | 117 | 3 | 2.6 | 57.0 | 0–5.4 |
2019 | 191 | 5 | 2.6 | 44.1 | 0.3–4.9 |
22020 | 0 | -- | NE | -- | -- |
2021 | 2 | -- | -- | -- | -- |
High water and missed trap periods resulted in few fish tagged at the screw trap in 2017.
Trap not fished in 2020 because of the COVID-19 pandemic.
To date (November 27, 2022), two coho salmon PIT-tagged as juveniles in tributaries have returned to Bonneville Dam as adults. One was tagged in Rattlesnake Creek in 2017 and returned to Bonneville Dam on October 29, 2019, and the other was tagged in Buck Creek in 2018 and returned to Bonneville Dam on September 16, 2020.
Because the White Salmon River does not currently have any PIT-tag detection infrastructure or adult capture facilities, we do not know how many of the adults detected at Bonneville Dam returned to the White Salmon River to spawn. Instream PIT-tag detection systems in Buck and Rattlesnake Creeks would provide valuable data.
Genetic samples were taken from fish during both the screw trapping and electrofishing efforts. Genetic samples taken from
The breaching and removal of Condit Dam on the White Salmon River, Washington, in 2011 and 2012, successfully provided anadromous salmonids access to historical habitats. Anadromous salmonids began using newly accessible habitats quickly following the dam removal. Upon implementation of our study in 2016, we observed production of juvenile steelhead, coho salmon, and Chinook salmon upstream from our screw-trap site and production of juvenile steelhead and coho salmon in three main tributaries upstream from the former Condit Dam site. Steelhead and coho salmon from the White Salmon River subbasin have returned as adults to Bonneville Dam. These results are encouraging considering that our study period corresponded to poor marine survival of Columbia River anadromous stocks and sharp declines in adult returns to the Columbia River Basin (Fish Passage Center [FPC], 2021; Welch and others, 2020). Despite this recent basin‐wide decline, and relatively low tag numbers, anadromous juveniles that reared in the White Salmon subbasin were detected as returning adults at Bonneville Dam on the Columbia River.
The screw-trapping site at river kilometer 2.3 proved to be an effective location for generating estimates of steelhead and coho salmon smolts produced upstream from the site. Maximum smolt estimates for steelhead and coho salmon were 5,851 fish (standard error [SE] = 1,064; year = 2018) and 1,773 fish (SE = 375; year = 2019), respectively. These estimates likely do not reflect the full smolt-production potential of the White Salmon subbasin because they occurred during a period of declining returns of Columbia River stocks (FPC, 2021; Welch and others, 2020). Future smolt-trapping estimates would benefit from additional marked fish to reduce uncertainty. Additional trapping and tagging locations could provide added marked fish with which to estimate smolt migration. Additional years of monitoring are required to begin to understand full production capacity of the White Salmon River subbasin.
The estimates of steelhead and coho salmon smolts during 2016 may be low because of a shorter duration of sampling (2016 = 62 days, 2018 = 76 days, 2019 = 75 days, 2021 = 73 days), owing to trap damage, which ended sampling on May 28. The missed days occurred late in the season when daily counts generally tapered off. The percentages of steelhead smolts captured after May 28 during 2018, 2019, and 2021 were 6.7, 4.0, and 3.9 respectively; the percentages of coho smolts captured after May 28 during 2018 and 2019 were 32.0 and 9.2, respectively. However, additional years of smolt monitoring would provide data to help us better understand the timing of the run and confidently estimate the percentage of the smolt run potentially missed during 2016.
Data from PIT-tagged fish showed that some steelhead and coho salmon smolts captured at the screw trap originated in tributaries upstream from the Condit Dam site. We were not able to evaluate the proportion of steelhead and coho salmon smolt production from tributaries and main-stem rearing areas. Further monitoring and outmigrant traps or PIT-tag infrastructure would serve to address questions of smolt origin and identify production areas or areas worthy of protection or restoration.
Although the primary goal of the screw trap was to estimate steelhead and coho salmon smolts, we also collected data on other species and life stages. Fry and parr steelhead, coho salmon, and Chinook salmon were captured, suggesting that there are multiple life stages and life histories likely using the improved habitat downstream from the former dam site. Chinook and Coho salmon spawn there, and although steelhead spawning distribution is unknown, downstream moving parr likely rear for at least some time in the main-stem habitat. Downstream movements of steelhead parr have been noted in other Columbia River tributaries (
Capture of fry was highly variable by day and year (particularly with Chinook salmon). We suspect that variable daily capture of fry was influenced by the operation of the live-box cleaning drum. When there was little debris in the trap and the cleaning drum was working, the fry were rotated out of the live box on the drum (this effect likely also applies to steelhead and coho salmon fry). We periodically disabled the cleaning drum to capture Chinook fry for genetic sample collection.
Yearly variability in Chinook and coho salmon fry was potentially influenced by high flow events that occurred after spawning (Chinook spawning, September–November; coho salmon spawning, October–January) and may have caused redd scour and egg-to-fry mortality. The river upstream from the screw-trap site is confined and subject to much bedload movement in the event of high flow. We captured few fry during 2016 and 2021; both brood years had high flow events that occurred after much of the spawning period (December 8, 2015, discharge >113 cubic meters per second [m3/s], estimated 25-year event; January 13, 2021, discharge = 133 m3/s). No coho salmon were found at our sample sites in Rattlesnake and Buck Creeks during summer 2020, indicating a lack of spawning or poor spawning success in brood year 2020, the fish from which year would have smolted in 2021.
Steelhead and coho salmon have used Mill, Buck, and Rattlesnake Creeks following removal of Condit Dam. Juvenile salmonid abundance estimates at the Buck Creek site following Condit Dam removal were greater in all years than in the 2 years sampled prior to Condit Dam removal, suggesting that Buck Creek may have been below carrying capacity prior to removal. Variability of juvenile salmonid abundance was pronounced in Rattlesnake Creek prior to and following Condit Dam removal. Juvenile coho salmon were not found in all years at our abundance sampling sites in Buck (none found in 2020) and Rattlesnake Creeks (none found in 2016 and 2020). Additional sampling in Buck Creek is warranted to determine potential coho salmon use upstream from the modified water diversion and in Buck and Rattlesnake Creeks to determine consistency of use and upstream extent.
Numerous factors could have influenced variation in abundance of juvenile
Interesting questions were raised regarding movement of juvenile steelhead between the White Salmon and Hood Rivers. Movements that we have documented include (1) the capture of steelhead smolts in the screw trap, which originally were tagged with passive integrated transponder (PIT) tags in the Hood River the prior year; and (2) detections at the PIT-tag detection system at the mouth of the Hood River (PTAGIS site code = HRM) of steelhead tagged in the White Salmon River subbasin. These data show that some fish are leaving the Hood and White Salmon Rivers as parr. This movement may be density-dependent movement or a life-history expression independent of abundance. Preliminary genetic analysis of screw-trap and main-stem electrofishing showed that there is a component of steelhead in the White Salmon with close relation to the Hood River, suggesting a possible metapopulation (
The return of natural-origin adults from steelhead and coho salmon PIT-tagged at the smolt trap and in tributaries of the White Salmon River is encouraging. Although our sample sizes were small, smolt-to-adult returns to date (November 27, 2022) from the smolt trap to Bonneville Dam were similar to recent estimates from wild steelhead in the Hood River, Oregon (
Data from our study suggest that natural recolonization of anadromous salmonids is occurring in the White Salmon River subbasin. Ten years following removal of Condit Dam, viable steelhead and coho salmon smolts are being produced upstream from the former dam site. Steelhead and coho salmon are using tributaries for spawning and rearing. Spring and fall run Chinook salmon have access to and have used new spawning areas downstream and upstream from the former dam site, and natural-origin steelhead, coho salmon, and Chinook salmon adults are returning.
Although results and research to date (December 2022) are encouraging, much remains to be learned. Long-term monitoring and research would help to assess the pace of recolonization and basin capacity, particularly because this study period had some of the lowest Columbia River Basin adult salmon returns ever. Additionally, the full extent of dam removal effects and recolonization may take decades to be realized (
All data from the White Salmon screw trapping are in Washington Department of Fish and Wildlife’s Juvenile Migrant Exchange Database. All PIT-tag data from screw trapping and electrofishing were submitted to the PTAGIS database (Coordinator ID = IGJ; Site Codes = WHITSR, BUCK3C, RATTLC). Electrofishing data are currently owned and archived by Yakama Nation Fisheries, Yakama Klickitat Fisheries Project. Genetics data for year 2016
For information about the research in this report, contact
Director, Western Fisheries Research Center
U.S. Geological Survey
6505 NE 65th Street
Seattle, Washington 98115-5016
Manuscript approved on December 16, 2022
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