Prepared in cooperation with the U.S. Fish and Wildlife Service

Composition and Relative Abundance of 

Fish Species in the Lower White Salmon River, 

Washington, Prior to the Removal of Condit Dam

U.S. Department of the Interior

U.S. Geological Survey

Open-File Report 2011-1087
Cover:

 Photograph showing rotary screw trap collecting fish (background) and Carrie Munz preparing to remove fish from the rotary screw trap

(foreground) in the White Salmon River, Washington. Photograph by Brady Allen, USGS, WFRC, Columbia River Research Laboratory.

 Top Inset: Salmonid fry collected by a rotary screw trap in the White Salmon River, Washington. Photograph by Brady Allen, 

 USGS, WFRC, Columbia River Research Laboratory.

 Bottom Inset: Wild fall Chinook salmon fry stained with Bismarck brown (top), wild fall Chinook salmon (middle), and hatchery fall 

 Chinook salmon (bottom) stained with Bismarck brown. Photograph by Brady Allen, USGS, WFRC, Columbia River Research Laboratory.
Composition and Relative Abundance of Fish Species in 

the Lower White Salmon River, Washington, Prior to the 

Removal of Condit Dam 

By M. Brady Allen and Patrick J. Connolly 

Prepared in cooperation with the U.S. Fish and Wildlife Service 

Open-File Report 2011-1087 

U.S. Department of the Interior 

U.S. Geological Survey 
U.S. Department of the Interior 

KEN SALAZAR, Secretary 

U.S. Geological Survey 

Marcia K. McNutt, Director 

U.S. Geological Survey, Reston, Virginia: 2011 

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Although this report is in the public domain, permission must be secured from the individual 

copyright owners to reproduce any copyrighted material contained within this report. 

Suggested citation: 

Allen, M.B., and Connolly, P.J., 2011, Composition and relative abundance of fish species in the 

Lower White Salmon River, Washington, prior to the removal of Condit Dam: U.S. Geological Survey 

Open-File Report 2011-1087, 32 p. 
iii 

Contents 

Abstract ......................................................................................................................................................................... 1

Introduction.................................................................................................................................................................... 2

Study Area..................................................................................................................................................................... 4

Methods......................................................................................................................................................................... 4

Results........................................................................................................................................................................... 6

Discussion ..................................................................................................................................................................... 9

Acknowledgments ........................................................................................................................................................13

References Cited..........................................................................................................................................................13 

Figures 

Figure 1. Map of the lower White Salmon River highlighting the location where the rotary screw trap was 

installed from March through June 2006–09, and the location of efficiency releases upstream of the trap 

at river kilometer (rkm) 2.3........................................................................................................................................... 15

Figure 2. Daily average White salmon River flow (ft3/s) during the period of trap operation from USGS gage number 

14123500 at river kilometer 3.1 and Bonneville Pool level (ft above sea level) measured at USGS gage number 

14128600 at river kilometer 244 of the Columbia River .............................................................................................. 16

Figure 3. Average number of age-0 Chinook salmon (not including hatchery released fish) captured per day by the 

rotary screw trap for each year of operation at river kilometer 1.5 of the White Salmon River, Washington, March–

June 2006-09............................................................................................................................................................... 17

Figure 4. Average number of age-1 or older Chinook salmon captured per day by the rotary screw trap for 

each year of operation at river kilometer 1.5 of the White Salmon River, Washington, March–June 2006–09............ 18

Figure 5. Average number of age-0 steelhead captured per day by the rotary screw trap for each year of 

operation at river kilometer 1.5 of the White Salmon River, Washington, March–June 2006–09 ................................ 19

Figure 6. Average number of age-1 or older steelhead (not including hatchery fish) captured per day by the rotary 

screw trap for each year of operation at river kilometer 1.5 of the White Salmon River, Washington, March–June 

2006–09....................................................................................................................................................................... 20

Figure 7. Average number of age-0 coho salmon captured per day by the rotary screw trap for each year of 

operation at river kilometer 1.5 of the White Salmon River, Washington, March–June 2006–09................................. 21

Figure 8. Average number of age-1 or older coho salmon captured per day by the rotary screw trap for each 

year of operation at river kilometer 1.5 of the White Salmon River, Washington, March–June 2006–09..................... 22

Figure 9. Length-frequency histograms of coho salmon and steelhead collected by electrofishing a 4.5-m 

swath of the left margin of the White Salmon River, at river kilometers (rkm) 1.5, 2.3, and 4.2, Washington, 2006 .... 23

Figure 10. Length-frequency histograms of coho salmon and steelhead collected by electrofishing a 4.5-m 

swath of the left margin of the White Salmon River at river kilometers (rkm) 1.5, 2.3, and 4.2, Washington, 2007.. ... 24

Figure 11. Length-frequency histograms of coho salmon and steelhead collected by electrofishing a 4.5-m 

swath of the left margin of the White Salmon River at river kilometer (rkm) 1.5, 2.3, and 4.2, Washington, 2008 ....... 25

Figure 12. Length-frequency histograms of coho salmon and steelhead collected by electrofishing a 4.5-m 

swath of the left margin of the White Salmon River at river kilometer (rkm) 1.5, 2.3, and 4.2, Washington, 2009 ....... 26
iv

Tables 

Table 1. Weekly total number of age-0 Chinook salmon, steelhead, and coho salmon captured at the 

rotary screw trap at rkm 1.5 in the White Salmon River, Washington, March–June 2006–09...................................... 27

Table 2. Weekly total number of age-1 or older Chinook salmon, steelhead, and coho salmon captured at 

the rotary screw trap at rkm 1.5 in the White Salmon River, Washington, March–June 2006–09................................ 28

Table 3. Rotary screw trap installation date, number of days fished, and the number of genetic samples 

collected at river kilometer 1.5 of the White Salmon River, Washington, 2006–09...................................................... 29

Table 4. Total number of fish and amphibian species, other than Chinook salmon, coho salmon, and steelhead, 

caught at a rotary screw trap at river kilometer 1.5 inn the White Salmon River, Washington, for each year of 

operation, March–June 2006–09 ................................................................................................................................. 29

Table 5.Number of hatchery (H) and wild (W) Chinook salmon and steelhead that were released and recaptured to 

estimate trapping efficiency of a rotary screw trap at river kilometer 1.5 on the White Salmon River, Washington ..... 30

Table 6.Number of Chinook salmon captured at a rotary screw trap at rkm 1.5 and total escapement estimates of 

tule and upriver bright (URB) fall Chinook salmon during the days the trap operated in the White Salmon River, 

Washington.................................................................................................................................................................. 30

Table 7. River kilometer (rkm), year, and number of fish by species and age class (greater than or less than 

105 mm fork length) that were collected during electrofishing surveys from three sites in the White Salmon River, 

Washington.................................................................................................................................................................. 31

Table 8. Fish health report results from fish collected in the White Salmon River and submitted to the U.S. 

Fish and Wildlife Service’s Lower Columbia River Fish Health Center, 2006–09 ........................................................ 32
v

Conversion Factors 

Multiply By To obtain 

Length 

inch (in.) 25.4 millimeter (mm) 

foot (ft) 0.3048 meter (m) 

mile (mi) 1.609 kilometer (km) 

yard (yd) 0.9144 meter (m) 

Volume 

ounce, fluid (fl. oz) 0.02957 liter (L) 

pint (pt) 0.4732 liter (L) 

quart (qt) 0.9464 liter (L) 

gallon (gal) 3.785 liter (L) 

cubic inch (in3

) 0.01639 liter (L) 

Flow rate 

cubic foot per second (ft3/s) 0.02832 cubic meter per second (m3/s) 

Mass 

ounce, avoirdupois (oz) 28.35 gram (g) 

Temperature in degrees Celsius (°C) may be converted to degrees Fahrenheit (°F) as follows: 

°F=(1.8×°C)+32 

Temperature in degrees Fahrenheit (°F) may be converted to degrees Celsius (°C) as follows: 

°C=(°F-32)/1.8 
vi

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Composition and Relative Abundance of Fish Species in 

the Lower White Salmon River, Washington, Prior to the 

Removal of Condit Dam 

By M. Brady Allen and Patrick J. Connolly 

Abstract 

Information about the composition and relative abundance of fish species was collected by a 

rotary screw trap and backpack electrofishing in the lower White Salmon River, Washington. The 

information was collected downstream of Condit Dam, which is at river kilometer (rkm) 5.2, and is 

proposed for removal in October 2011. A rotary screw trap was installed in the White Salmon River at 

rkm 1.5 and operated from March through June during 2006–09. All captured fish were identified to 

species and enumerated. Daily subsets of fish were weighed, measured, and fin clipped for a genetic 

analysis by the U.S. Fish and Wildlife Service. 

 Fall Chinook salmon (Oncorhynchus tshawytscha) were captured in the highest numbers 

(n=18, 640), and were composed of two stocks: tule and upriver bright. Almost all captured 

fall Chinook salmon were age-0, with only 16 (0.09 percent) being age-1 or older. 

 Tule fall Chinook salmon, the native stock, generally out-migrated from mid-March through 

early April. The tule stock was the more abundant fall Chinook salmon subspecies, comprising 

85 percent of those captured in the trap. 

 Upriver bright fall Chinook salmon comprised 15 percent of the Chinook salmon catch and 

generally out-migrated from late May to early June. 

 Coho salmon (O. kisutch) and steelhead trout (O. mykiss) were captured by the rotary screw 

trap in all years. Coho salmon were caught in low numbers (n=661) and 69 percent were age-0 

fish. Steelhead were slightly more abundant (n=679) than coho salmon and 84 percent were 

age-1 or older fish. 

Trap efficiency estimates varied widely (range, 0-10 percent) by species, fish size, and time of 

year. However, if we use only the estimates from efficiency tests where more than 300 wild age-0 

Chinook salmon were released, there was a mean trapping efficiency of 1.4 percent (n=4, median, 1.3 

percent, range, 0.3–2.4 percent) during the tule out-migration period, and a mean trapping efficiency of 

0.8 percent (n=2, range, 0.3–1.2 percent) during the upriver bright fall Chinook salmon out-migration 

period. 

When water levels in the White Salmon River declined in late summer, we electrofished the 

river margins in 2006–09 along three sites at rkm 1.5, 2.3, and 4.2. Age-0 steelhead were the most 

abundant fish captured (n=565, 62 percent), followed by age-0 coho salmon (n=222, 24 percent). In 

autumn, age-0 Chinook salmon were collected while electrofishing (n=40, 4 percent). This suggests that 

there may be a migration in the autumn as age-0 Chinook salmon or in the spring as age-1 Chinook 

salmon, since the Chinook salmon that migrate as age-0 fish in the spring departed several months 

1
earlier (the typical life history for fall Chinook salmon). The only age-1 salmonids captured while 

electrofishing were steelhead (n=84, 9 percent). Fish distribution and abundance will likely change 

when Condit Dam is removed and anadromous fish gain access to their historical spawning and rearing 

areas in the White Salmon River. These findings should provide a baseline with which to compare 

juvenile fish species composition and relative abundance after Condit Dam is removed. 

Introduction 

The completion of Condit Dam in 1913 blocked anadromous fish runs at river kilometer (rkm) 

5.1 of the White Salmon River in southern Washington. When this study was initiated, Condit Dam was 

scheduled for removal in October 2009 by PacifiCorp, the owner and operator of the dam. Condit Dam 

is scheduled for removal in October 2011. Because it had been more than 20 years since there had been 

juvenile salmonid sampling efforts, the species composition and amount of juvenile salmonid 

production occurring in the White Salmon River downstream of Condit Dam were unknown. The last 

evaluation of juvenile production in the White Salmon River was conducted by Seiler and Neuhauser in 

1984 with an incline plane trap. By collecting new information about natural production, species 

composition, distribution, and genetic information of fish species within the White Salmon River, we 

will be more able to predict and track the effects that dam removal could have on important fish species 

such as Chinook salmon (Oncorhynchus tshawytscha), coho salmon (Oncorhynchus kisutch), 

steelhead/rainbow trout (Oncorhynchus mykiss) (hereafter referred to as steelhead), Pacific lamprey 

(Lampetra tridentata), bull trout (Salvelinus confluentus), and sea-run cutthroat trout (Oncorhynchus 

clarki clarki). 

Dams disrupt longitudinal habitat connectivity for migratory fish species, such as salmonids 

(Hall and others, 2010). Dams without fish passage, like Condit Dam, physically block access for fish, 

but even with fish passage, dams can degrade fish habitat by altering physical processes. Dams in rivers 

modify the aquatic habitat by altering sediment transport, nutrient transport, hydrologic regime, and 

temperature (Heinz Center, 2002). Dams can cause extirpation of salmonid species that tend to spawn 

higher in watersheds, such as summer steelhead and spring Chinook salmon, by blocking access to their 

historical spawning areas. They also can alter the spawning distribution and success of fish that tend to 

spawn in the lower portions of watersheds, such as fall Chinook salmon. Dams may degrade 

downstream spawning and rearing habitat by reducing sediment transport and altering the flow regime, 

which can reduce spawning gravel availability and result in an armoring of the streambed (Allan and 

Castillo, 2007). The loss of habitat connectivity and aquatic habitat can lead to species decline and 

extirpation. 

It has largely been assumed and predicted by modeling efforts (Normandeau, 2004; Allen and 

Connolly, 2005) that reconnecting the upper White Salmon River to the Columbia River will result in 

increased natural production of several anadromous fish species. Although this may be a reasonable 

assumption, a large question remains as to which natural stocks would be most likely to succeed by 

natural recolonization, and which stocks would be available to be incorporated into hatchery-based 

reintroduction. Before considering hatchery reintroductions, managers needed to know what species and 

stocks were present, what their genetic relatedness was to hatchery stocks, and what the abundance of 

those species were in order to recognize needs and opportunities for fisheries restoration in the White 

Salmon River system. 

2
Determination of whether natural-origin (wild) fall Chinook salmon in the lower White Salmon 

River (downstream of Condit Dam) were genetically distinct from hatchery stocks of fall Chinook 

salmon that stray and spawn in the White Salmon River was a key decision factor in U.S. Fish and 

Wildlife Service’s (USFWS) restoration strategy. Both tule and upriver bright (URB) fall Chinook 

salmon were known to spawn in the White Salmon River (Normandeau, 2004). Tule fall Chinook 

salmon typically spawned earlier (late September) than URB fall Chinook salmon (November). Based 

on recovery of coded wire tags from carcasses, hatchery-origin tule fall Chinook salmon from USFWS’s 

Spring Creek National Fish Hatchery (NFH), URBs from the Little White Salmon NFH, and tule and 

URB fall Chinook salmon from Bonneville Hatchery (Oregon Department of Fish and Wildlife) were 

spawning in the White Salmon River (Pastor, 2004). Carson-stock spring Chinook salmon from the 

Little White Salmon NFH or Carson NFH also may have been spawning in low numbers in the White 

Salmon River. For more than 100 years, the Spring Creek NFH, located 1.8 km downstream of the 

confluence of the White Salmon and Columbia Rivers, has raised the tule stock of fall Chinook salmon 

that is native to the White Salmon River. From 1901 to 1964, a nearly uninterrupted collection of adult 

tule fall Chinook salmon occurred from the lower White Salmon River for spawning at Spring Creek 

NFH. The stock collected from White Salmon River was developed over many generations and has been 

identified by the Columbia Basin Fish and Wildlife Authority and regional fishery biologists for 

reintroduction into the White Salmon River after Condit Dam removal. Because of the impending dam 

removal, the results of the genetic relatedness between wild spawning Chinook salmon populations in 

the White Salmon River and USFWS hatchery facilities was deemed a high priority of the USFWS and 

the organization provided internal funding for this genetic analysis. 

We intended to take advantage of the unique opportunity that exists to link the dam removal 

efforts proposed in the White Salmon River with efforts in the Elwha River. Two Elwha River dams, 

which are similar in size to Condit Dam, were slated for removal in approximately the same time frame 

as Condit Dam. To adequately compare and contrast fish response to dam removal in these two systems, 

a concerted effort was expended to characterize fish use, using similar methodology as used in the 

Elwha River (Connolly and Brenkman, 2008), before the dams are removed. This approach was 

intended to fill an information gap at a low cost considering the logistical difficulties of sampling the 

lower White Salmon River, due to the difficult access, river size, and high water velocity in the lower 

river. When tributary habitat and mainstem habitat are available to fish after Condit Dam removal, it is 

expected that the success of some fish species would change, which would possibly alter the species 

distribution, age composition, and growth conditions. Therefore, we characterized the existing fish 

populations in the margins of the mainstem White Salmon River downstream of Condit Dam to provide 

a baseline from which to compare that change. 

The objectives of the work were to: 

 Determine the fish assemblage and relative abundance of fish in the lower White Salmon 

River as one index of productivity. 

 Determine the relatedness of Chinook salmon collected in the White Salmon River compared 

with those returning to Spring Creek NFH. 

 Assess whether hybridization was occurring between URB Chinook salmon and tule Chinook 

salmon. 

The results of the USFWS’s genetic analysis will be used to guide Chinook salmon 

reintroduction plans for the White Salmon River. The results of this study will help maximize learning 

about fish response to dam removal. 

3
Study Area 

The study area was from the mouth of the White Salmon River to the base of Condit Dam at rkm 

5.2 (fig. 1). Bonneville Dam, at rkm 234 on the Columbia River, was completed in 1938 and inundates 

the lower White Salmon River creating slack water 1.5 rkm upstream of its confluence with the 

Columbia River. Base water flow and temperature in the lower White Salmon River are maintained by 

groundwater, glacial melting from Mount Adams, and Condit Dam operations. At Condit Dam, which 

creates a run-of-the-river reservoir (Northwestern Lake), most river flow is bypassed for 1.9 km 

downstream to a powerhouse located at rkm 3.2, where it rejoins the rest of the river flow. The bypass 

section can have flows as low as 30 ft3/s (Normandeau and Associates, 2004). There is a USGS 

streamflow gaging station (Underwood, gage# 14123500) about 200 m downstream of the bypass 

section and powerhouse at rkm 3.0 (fig. 2). The release site for testing trap efficiency was at rkm 2.3, 

where a road accessed USFWS rearing ponds and the White Salmon River. The rotary screw trap was 

installed at rkm 1.5, which was about 20 m upstream of the most downstream riffle in the White Salmon 

River. The closest gage to measure the Bonneville pool level was in Stevenson (gage # 14128600), 

which was located 8 km upstream of Bonneville Dam, and 29 km downstream of the White Salmon 

River confluence with the Columbia River (fig. 2). Water depth and velocity at the trap location were 

variable due to operations at both Condit and Bonneville Dams. Bonneville pool elevation fluctuated up 

to a meter within a few hours. The location of the trap was inundated when Bonneville pool elevations 

were high. The discharge in the White Salmon River fluctuated rapidly due to power generation at 

Condit Dam. This rapid change in discharge altered the depth and velocity of water at the trap location. 

The lower White Salmon River below Condit Dam is within the Columbia River Gorge National 

Scenic Area and is sparsely developed with limited access. Limited information exists on fish stocks in 

the White Salmon River below Condit Dam, but the White Salmon River Subbasin Plan (Normandeau 

and Associates, 2004) indicates that coho salmon, tule fall Chinook salmon, upriver bright fall Chinook 

salmon, resident and anadromous O. mykiss, chum salmon O. keta, spring Chinook salmon, pink salmon 

O. gorbuscha, and sea-run cutthroat may use the lower White Salmon River, with the latter four species 

dwindling or sporadic in number. 

Methods 

In early March of each year, 2006–09, a 5-foot rotary screw trap (E.G. Solutions, Corvallis, 

Oregon) was installed and operated in the White Salmon River at rkm 1.5 (fig. 1). Because much of the 

limited amount of spawning gravel occurred near or below the lowermost portion of flowing water, the 

rotary screw trap was installed as close to the inundated portion of the White Salmon River as possible 

to collect salmonids produced from that area. During the 4 years of operation, the date of installation 

and number of days that the trap operated varied (table 1). The trap was operated 5 days per week in 

2006, 2008, and 2009. In 2007, the trap was operated 7 days per week. When operating, the trap was 

checked daily for fish. The cone of the trap was raised, rendering it inoperable, for about 1 week each 

year when hatchery fish were released upstream of our trap by the State of Washington (10,000 summer 

steelhead and 10,000 winter steelhead smolts per year). In 2006, 2008, and 2009, the cone was raised 

after the fish were collected on Fridays and then lowered back into the sampling position on Monday 

mornings. Trap efficiency tests were conducted two times in 2006, daily in 2007, and three times each 

in 2008 and 2009. The trap was operated for at least 11 consecutive days after all efficiency tests to 

maintain equal likelihood of recapture. In 2007, 2008, and 2009, trap operation continued until the last 

week of June or until less than 10 Chinook salmon were captured in the trap for 7 consecutive days. 

4
The methods for installing and operating the rotary screw trap generally followed those 

described in Volkhardt and others (2007). Each sampling day, prior to checking the live box in the 

rotary screw trap, the number of cone revolutions per minute, weather conditions, sampling time, water 

clarity, and water depth at the trap were recorded. Debris was removed from the live box, and captured 

fish were netted into buckets and transported to shore. After the fish were transported to shore, as many 

as 60 fish of each species were anesthetized per day with 50 mg/L tricaine methanesulfonate (MS-222), 

measured for fork length (FL) to the nearest millimeter, weighed to the nearest 0.1 g, examined for 

external parasites and diseases, and scored for smolt condition (1 = parr, 2 = intermediate, and 3 = 

smolt). All additional fish that were collected each day were identified to species, origin (absence of an 

adipose fin indicated the fish was of hatchery origin), and counted. To estimate the proportion of tule 

Chinook salmon versus URB Chinook salmon, fin clips were submitted to the USFWS Abernathy Fish 

Technology Center (AFTC) for genetic analysis. To ensure reasonable sample size for the genetic 

analysis, fin clips were collected and preserved in 100 percent ethanol from as many as 30 fish of each 

species per day [fry (< 80 mm FL) and smolts (≥ 80 mm FL) were considered separately], but no more 

than 60 genetic samples per species each week. Fin clips from most other non-hatchery origin salmonids 

also were collected and preserved for potential future analysis. Incidental fish mortalities were put on 

ice and delivered to the USFWS’s Lower Columbia River Fish Health Center (LCRFHC) to provide a 

thorough disease profile as part of the USFWS’s National Wild Fish Health Survey. In 2009, 60 

Chinook salmon fry were submitted for a disease profile early in the trapping season, and 60 more were 

submitted late in the trapping season to ensure adequate sample size for disease profile. The fish 

provided to the LCRFHC were given a rigorous inspection for disease by testing or microscopic 

observation. Disease screening included bacterial (bacterial kidney disease, coldwater disease, 

columnaris, emphysematous putrefactive disease, furunculosis, enteric redmouth), viral (infectious 

pancreatic necrosis, infectious hematopoietic necrosis, viral hemorrhagic septicemia), and parasitic 

agents (whirling disease, Ceratomyxa, digenetic trematodes, Myxobolus kisutchi, Myxidium minteri, 

Hexamita, Gyrodactulus, Scyphidia, Heteropolaria). 

Efficiency tests were conducted to estimate the fraction of salmonids outmigrating from the 

White Salmon River that were captured in the trap. In 2006, the pilot year, an efficiency test was done 

early and another one late in the sampling season to test the logistics and ensure the feasibility of 

estimating capture efficiency. To test the trap efficiency, salmonids were marked with 16 mg/L 

Bismarck Brown Y biological stain (Sigma Chemical Company, St. Louis, Missouri) for the duration of 

time it took to transport them to the release location (about 35–45 minutes). Fish were transported by 

boat from the screw trap location to a nearby vehicle, which then took the fish to an access point at the 

USFWS raceway at rkm 2.3, where they were released (fig. 1). From March 7 through April 27, 2007, 

fish were transported for efficiency tests daily. In 2008 and 2009, about 500 hatchery Chinook salmon, 

which were the same subspecies and similar in size as the wild Chinook salmon, were used to boost the 

sample size of the efficiency tests. We used hatchery Chinook salmon as surrogates to increase our 

sample size in 2008 and 2009 because a low proportion of fish that were transported for efficiency tests 

in 2007 were recaptured (10 of 914 fish). Efficiency tests were conducted using 500 hatchery Chinook 

salmon on each of three occasions in each year. During the peak tule fall Chinook salmon outmigration, 

500 tule fall Chinook salmon from USFWS’s Spring Creek NFH were marked with Bismarck Brown 

and adipose fin clips before being released upstream of the trap in 2008 and 2009. During the period 

between the peak tule and peak URB outmigration, another 500 tule fall Chinook salmon fry were

similarly marked and released for an efficiency test in 2008 and 2009. During the peak URB 

outmigration period, 500 URB fry from the USFWS’s Little White Salmon NFH were similarly marked 

and released as an efficiency test. During each efficiency release in 2008 and 2009, all fish captured at 

5
the trap also were marked with Bismarck Brown Y and released upstream in addition to the hatchery 

releases to increase the sample size of potential recaptures, and to compare the wild and hatchery fish 

recapture rates. 

Capture efficiency, defined as the percentage of fish passing the trap that were captured 

(Thedinga and others, 1994), needs to be estimated if an estimate of the total number of fish migrating is 

desired. Trap efficiency estimates were calculated by the use of the equation: 

 E = R / M, (1) 

where E is the estimated trap efficiency, R is the number of marked fish recaptured, and M is the 

number of marked fish released. Fish production estimates were calculated by use of the equation: 

 A = C / E, (2) 

where A is the estimated abundance, and C is the total catch for the period (Thedinga and others, 1994). 

Similar to methods implemented in the Elwha River system (Connolly and Brenkman, 2008), 

backpack electrofishing was conducted in the White Salmon River at three accessible and wadeable 

locations (rkm 1.5, 2.3, and 4.2), all of which were downstream of Condit Dam (at rkm 5.1). At each 

location, the electrofishing was done as a single upstream pass within a 4.5 m swath of the wadeable 

margin of the river left bank (when looking downstream) in accessible mainstem pools and non-pools. 

The area and proportion of the habitat unit that was electrofished was measured. All salmonids, as well 

as a representative subsample of other fish species encountered, were collected. The percentage of area 

of the 4.5 m swath that was too fast or too deep to effectively electrofish was subtracted from the total 

for each habitat unit. At least two consecutive habitat types, pools and non-pools, were sampled at each 

site. Attempts were made to keep the sampling effort as consistent as possible between sites and years. 

The method used in the Elwha River included side channels as separate habitat types, however, there 

were no side channels in the White Salmon River downstream of Condit Dam to include for this survey. 

The river margins served as index areas to document juvenile fish assemblage and relative abundance. 

Results 

There was a bi-modal distribution in Chinook salmon fry abundance captured in the trap in all 

years of sampling (fig. 2). Of the two periods of increased abundance, the first peak was the largest in 

2006, 2008, and 2009 and occurred in mid-March through early April (fig. 2, table 1). After this initial 

peak, low numbers of Chinook salmon were captured (generally from the third week in April through 

late May), but another peak in Chinook salmon fry abundance occurred in late May to early June (fig. 2, 

table 1). In 2007, much lower numbers of fish were captured during the first out-migration peak than in 

other years, but the second peak was similar to other years. 

Age-0 Chinook salmon were the numerically dominant salmonid captured at the trap in all years 

of operation. Although the trap was fished in the same location, the total number of fish captured in the 

screw trap varied nine-fold between years (table 1). Fewer Chinook salmon were captured in 2007 

(n=1,070) than the other years of trap operation. However in 2007, we captured the highest number of 

steelhead (n=54) and coho salmon (n=195) fry. The greatest number of Chinook salmon fry (n=9,986) 

were captured in 2009, with more than double the next highest year’s catch. Chinook salmon averaged 

39 mm FL, with lengths less than 32 mm and visible yolk-sacks were captured during both the early and 

late peaks in out-migration in 2006–09. Chinook salmon as small as 37 mm were captured in May 

(ordinal week 21), indicating that they were still hatching during this period. 

6
Yearling Chinook salmon were rarely captured at the trap (table 2). Eleven or fewer yearling 

Chinook salmon were captured annually, with no apparent pattern in timing (fig. 3). Fork lengths of 

yearling Chinook ranged from 80 to 190 mm. In 2006, smolting coho salmon with little or no parr 

marks and highly eroded anal fins were incorrectly identified as yearling Chinook salmon. Tissue 

samples were collected from these fish, and genetic analysis identified them as coho salmon. Fish 

biologists working in adjacent watersheds corroborated that these coho salmon were likely hatchery fish 

released in nearby tributaries that strayed into the White Salmon River, where no hatchery coho salmon 

were released (J. Zendt, Yakama Nation fisheries biologist, oral commun., 2007). 

Few age-0 steelhead were captured throughout the trap operations, with an average of 0– 4 fish 

per day per week in late May and early June (fig. 4), and a maximum of 13 fish in a single day. 

Naturally produced (adipose fin present) age-1 or older steelhead were captured in low numbers 

(ranging from 0 to 8 fish per day per week), with a peak in numbers from late April through mid-May 

(fig. 5). Steelhead were the most common age-1 or older salmonid (table 2). Trap operation was halted 

each year for about 1 week in early April or late May to allow 20,000 hatchery steelhead (adipose fin 

removed), released by Washington Department of Fish and Wildlife upstream of our trap, to out-migrate 

without overwhelming the trap. However, an increase in the captured number of hatchery steelhead 

occurred for several weeks (ordinal weeks 19–23) after release in each year of trap operation (table 2). 

Age-0 coho salmon were captured at the trap in low numbers, with an average of 0–10 fish 

captured per day per week (fig. 6) and a maximum of 26 fish captured in single day. They were 

typically captured from mid-March to mid-June. Coho salmon less than 40 mm were captured in the 

trap throughout the sampling period, indicating a wide range in emergence times (table 1, fig. 6). Age-1 

coho salmon were occasionally captured in the trap. We believe that most of the age-1 coho salmon 

captured in 2006 were unmarked (adipose fin present) hatchery fish. Age-1 coho salmon were not 

captured in 2007, 18 were captured in 2008, and 15 were captured in 2009. The proportion of wild 

versus hatchery coho salmon was not certain because hatchery coho salmon were not adipose fin 

clipped. However, some of the coho salmon captured in 2006 and 2009 were captured after hatchery 

releases in nearby watersheds and were pale with eroded fins, indicating that they were likely of 

hatchery origin (table 2, fig. 7). 

The period that the rotary screw trap operated and the number of days fished each year varied 

(tables 1 and 3). In the pilot year (2006), the trap began operating March 27 and operated 5 days per 

week until May 18. Trap operations were halted on May 20, 2009, because the number of Chinook 

salmon captured was approaching our permitted number to handle. A modification to increase the 

allowed take was permitted on May 29, 2009, and trap operation resumed. A total of 492 fin clips were 

collected for genetic analysis (table 3). Fin clips collected for genetic analysis were largely limited to 

2006, 2007, and 2008. Chinook salmon was the focus of the genetic analysis and more than 1,500 tissue 

samples were submitted to the USFWS (table 3). Additional tissue samples, taken from steelhead and 

coho salmon, were archived for potential future analysis. 

7
A variety of species other than salmonids were captured in the trap in all years of operation 

(table 4). Lamprey were the most common of the non-salmonids in the trap in most years. Many of the 

lamprey were gravid females less than 120 mm in length, which were likely brook lamprey (Lampetra 

richardsoni), but many others of similar size were immature, with no developed eyes. Sculpin (Cottus 

spp.) were the next most common species captured in the trap. The largescale sucker (Catastomus 

macrocheilus) that were captured typically were large adults (greater than 400 mm). One fry collected 

on March 29, 2006, was identified as a pink salmon, however, the specimen was very small (37 mm 

FL), and the species identification was tentative. Fish that were of unknown identity were either fry that 

were too undeveloped to identify (often with the egg yolk still evident), or mortalities that were too 

degraded to identify (often regurgitated from the captured salmonid smolts or sculpin). 

A number of methods were used to estimate capture efficiency of the screw trap. In 2006, there 

were two attempts at estimating trap efficiency using fish captured at the trap (table 5). In 2007, when 

fish were transported upstream for efficiency tests every day and the trap was fished 7 days per week, 

no steelhead smolts and 9 Chinook salmon fry were recaptured. This was after 708 Chinook salmon and 

134 steelhead smolts were transported in 43 consecutive efficiency releases. Because of the low 

numbers of recaptured fish in 2007, the efficiency estimates were lumped into an early estimate (1.3 

percent for fry, 0 percent for smolts) and a late estimate (1.2 percent for fry, 0 percent for smolts, table 

5). The transportation of fish for daily efficiency estimates ceased on April 27, 2007, because too few 

fish were being captured in the trap to be transported for efficiency testing, and only nine fish had been 

recaptured during the entire season. After April 27, 2007, the trap was operated 5 days per week until 

June 28, 2007. In 2008 and 2009, hatchery fall Chinook salmon from the USFWS’s Spring Creek NFH, 

and Little White Salmon NFH were used on three occasions in each year for tests of trap efficiency 

(table 5). In 2008 and 2009, the estimates of capture efficiency of hatchery and wild caught fish were 

calculated separately (table 5). In April 2008, 10.6 percent of the hatchery Chinook salmon and 2.4 

percent of the wild Chinook salmon were recaptured when released in similar numbers upstream on the 

same day (table 5). In early June 2009, 3.6 percent of hatchery Chinook salmon and 0.3 percent of wild 

Chinook salmon were recaptured when released upstream on the same day (table 5). Although fish were 

consistently captured in the trap, occasionally in high numbers, our tests indicate that the efficiency of 

the trap was low and inconsistent. The efficiency estimate ranged from 0 to 11 percent, and it was 

different based on fish size, species, origin (hatchery or wild), and the date of the test (table 5). 

However, when we restricted the use of efficiency tests to only those times when more than 300 wild 

age-0 Chinook salmon were released, there was a mean trapping efficiency of 1.4 percent (n=4, 

range=0.3–2.4 percent, median=1.3 percent) during the earlier tule Chinook salmon out-migration and a 

mean trapping efficiency of 0.8 percent (n=2, range=0.3–1.2) during the later URB Chinook salmon 

out-migration (table 5). When we restrict the use of efficiency tests to only those when more than 500 

hatchery Chinook salmon were released, there was a mean trapping efficiency of 5.9 percent (n=2, 

range=1.2–10.6 percent) during the tule Chinook salmon out-migration, and 2.7 percent (n=2, 

range=1.7–3.6 percent) during the URB Chinook salmon out-migration (table 5). Using an efficiency 

estimate of 1.4 percent, we calculated the wild tule Chinook salmon escapement during the days the trap 

operated to range from 42,760 to 578,062 fish (table 6). Using an efficiency estimate of 0.7 percent, we 

calculated the wild URB Chinook salmon escapement during the days the trap operated to range from 

58,991 to 218,111 fish. Escapement, calculated using efficiencies from hatchery releases, was about 

one-quarter of the escapement calculated using efficiency tests from wild fish releases (table 6). 

Because of the variability in efficiency estimates, and confounding factors relating to those estimates, 

we did not calculate a variance for these estimates, nor did we extrapolate to total escapement over the 

entire out-migration period. 

8
Electrofishing surveys, conducted in the autumn of each year (2006–09), indicated that steelhead 

and coho salmon were the numerically dominant salmonids in the margins of the White Salmon River 

downstream of Condit Dam at this time of year (table 7). We captured 649 steelhead, 222 coho salmon, 

and 40 Chinook salmon. Steelhead typically were captured in higher abundance in all years and at all 

three electrofishing sites. Coho salmon were captured at all electrofishing locations, but with high 

variability in abundance within sites among years. Most of the Chinook salmon (n=38) were captured at 

rkm 2.3; 78 percent of which were captured in 2009. These were likely age-0 fish, which averaged 82 

mm FL (median=80, mode=90, range=60–105). Chinook salmon were not captured at rkm 1.5, and only 

two were captured at rkm 4.2. 

Length-frequency analysis of steelhead and coho salmon indicated that all fish captured at rkm 

1.5 were age-0 (figs. 8–11). Too few Chinook salmon were collected during electrofishing to conduct a 

length-frequency analysis. In 2007, the electrofishing effort was reduced to shallow riffle habitat at rkm 

1.5, which was a subset of the area that was electrofished in 2006, 2008, and 2009. This was because of 

a large number of spawning or holding tule fall Chinook salmon adults in the larger area that was 

electrofished in 2006, 2008, and 2009. Age-1 steelhead (FL > 105 mm) were captured at rkm 2.3 and 

4.1 (table 7, figs. 8–11). Age-1 coho salmon were not captured at any site. The range in the lengths of 

steelhead (28–155 mm in 2009, fig. 11) was wider at rkm 2.3 and rkm 4.3 compared with rkm 1.5 (38–

70 mm FL in 2009, fig. 11) in all years of sampling (figs. 8–11). The habitat at rkm 1.5 had smaller 

substrate and slower velocity than the other electrofishing sites, which might influence the fish use and 

electrofishing efficiency when compared with the other sites. Age-0 coho salmon (46–100 mm FL) were 

consistently captured at all electrofishing sites and were on average larger than the age-0 steelhead (25–

105 mm, figs. 8–11). 

The greatest variety of fish species were collected at rkm 1.5, with lamprey, sculpin, longnose 

dace (Rhinichthys cataractae), and three-spined stickleback (Gasterosteus aculeatus) adding to the 

species composition (table 7). Sculpin were consistently the most abundant non-salmonid at all 

electrofishing sites. Lamprey were collected at rkm 1.5 and rkm 2.3 and averaged 137 mm long. Of the 

eight captured, six were mature with eyes, and two were ammocetes with undeveloped eyes. 

A total of 156 fish were submitted to the USFWS’s LCRFHC for disease analysis (table 8). Most 

(92 percent) of the fish submitted for disease analysis were fry collected in the spring by the screw trap, 

but five of the fish submitted were collected in the autumn when electrofishing. No disease agents were 

detected other than Epistylis in a single 141 mm FL steelhead that was collected while electrofishing 

(table 8). Overall, fish in the lower White Salmon River were nearly free of disease. 

Discussion 

Two distinct pulses of Chinook salmon were observed to out-migrate from the White Salmon 

River. The first pulse was from March to late April, and the second pulse was from mid-May to early 

June, with a transitional period during the first 2 weeks of May (fig. 2). The genetics analysis, 

conducted by USFWS, concluded that the early hatching and out-migrating fall Chinook salmon were 

tule fall Chinook salmon, which were closely related to Chinook salmon from Spring Creek NFH 

(Smith and others, 2009). Because Spring Creek NFH collected their Chinook salmon broodstock from 

the White Salmon River from 1901 to 1964, and because stray hatchery tule fall Chinook salmon were 

known to spawn in the lower White Salmon River (more than 30 to 86 percent of the tule Chinook 

9
salmon spawners in some years; Normandeau, 2004, p. 82), the genetic relatedness of the two stocks 

was not surprising. The later hatching and out-migrating Chinook salmon were URB stock that were 

genetically similar to fall Chinook salmon from the middle and upper Columbia River, as well as to the 

stock raised at USFWS’s Little White Salmon NFH (Smith and others, 2009). This genetic divergence 

between stocks was substantial, indicating very little interbreeding between the tule and URB stocks, or 

low survival of tule-URB hybrids. 

Tule fall Chinook salmon were the most abundant age-0 salmonid out-migrating from the lower 

White Salmon River. However, the adult URB Chinook salmon were the more abundant stock counted 

during spawning surveys in most years (Normandeau 2004, p. 75). Spawning URB Chinook salmon 

were five-fold more abundant than spawning tule Chinook salmon in 2006 (2007 age-0 out-migration), 

and nearly equal to that of tule spawner estimates in 2007 and 2008 (2008 and 2009 age-0 out-migration 

respectively, Washington Department of Fish and Wildlife, 2011). Prior to this study, the extent that the 

November spawning URB Chinook salmon affected egg-to-fry survival by superimposing on the redds 

of the earlier spawning (late September) tule Chinook salmon was unknown. Because spawning habitat 

was limited downstream of Condit Dam (Normandeau, 2004, p. 97), some amount of redd 

superimposition was thought to occur. If redd superimposition did occur downstream of Condit Dam, it 

did not affect tule Chinook salmon egg to fry survival such that the URB fry outnumbered the tule 

Chinook salmon fry (fig. 2). One possible reason for higher numbers of age-0 tule Chinook salmon 

being captured at the rotary trap is that the native stock (tule) were better adapted to conditions in the 

White Salmon River and had higher egg-to-fry survival when compared to the URBs. 

Relatively few tule fall Chinook salmon fry were captured in 2007 when compared with other 

years of trap operation (fig. 2). A high-flow event in November 2006 likely reduced the survival of the 

tule Chinook salmon eggs that had recently been laid. Some coho salmon and URB Chinook salmon 

spawned after the flow event and steelhead spawn in the spring, so the November 2006 flow event 

would not have affected their egg survival to the same extent. The low abundance of age-0 tule fall 

Chinook salmon in 2007 was therefore considered to be atypical. 

Similar to our findings, Chinook salmon were the most abundant salmonid captured in an incline 

plane scoop trap operated in the lower White Salmon River in 1983 and 1984 (Seiler and Neuhauser, 

1985). This trap was operated in about the same location as ours in 1983, but in 1984, it was installed 

farther upstream at the location of our efficiency releases (rkm 2.3). In 1983, the capture was 4,057 

Chinook salmon (hatchery and wild), 1,669 coho salmon, 92 wild steelhead smolts, 128 subyearling 

steelhead, and 12 steelhead fry. In 1984, the capture was 6,000 wild Chinook salmon, 4,463 coho 

salmon, 619 age-1 steelhead, and 42 steelhead fry. During the same years, the USFWS raceways at rkm 

2.3 were raising Chinook salmon and 1 million coho salmon were stocked upstream of Condit Dam as 

part of a pilot project. Therefore, the coho salmon and Chinook salmon relative capture rates were 

confounded by unmarked hatchery fish and were not comparable. However, the hatchery steelhead that 

were released upstream of the trap were fin-clipped and could be differentiated from wild production. 

The findings of Seiler and Neuhauser (1985) were similar to ours in terms of the relative abundance of 

each species, but the trap they used was an incline plane and not a rotary screw trap, their catch rates 

were confounded by other releases and the release of unmarked hatchery fish, and there was substantial 

variability in species abundance between years. 

There were many variables affecting the accuracy of trap efficiency estimates. Our estimates of 

trap efficiency were highly variable (range 0–10.6 percent), with too few age-1 or older fish released 

and/or recaptured to estimate trap efficiency for that age class. Trap efficiency generally was low for 

tests with wild Chinook salmon fry (range 0.3–2.4 percent). Only two of six of those tests recaptured 

more than five fish. Schwarz and Taylor (1998) suggest that there may be bias in tests with so few 

10
recaptures. Therefore, we recognize that the estimates are likely biased. The Bismarck Brown Y staining 

method appeared to work well, with stained fish easily identified at least 1 week after marking. 

However, marked fish may have migrated past the trap well after being released. This biological dye has 

been reported to fade after about 2 weeks post immersion, but temperature and other environmental 

factors may alter dye retention (Ewing and others, 1990). Another factor affecting trap efficiency 

estimates was that the fry captured at the trap were not necessarily migrating, and may have been simply 

drifting downstream to find rearing habitat in slower water (Quinn, 2005). If this was the case, the fry 

that were transported upstream may have found rearing habitat prior to reaching the trap, which violates 

the assumption that fish transported upstream were actively migrating (Volkhardt and others, 2007). 

Because so few fish were recaptured when conducting daily efficiency tests in 2007, we used 

hatchery Chinook salmon as surrogates for wild caught fish in 2008 and 2009. While releasing hatchery 

fish did increase our sample size, in all but one occasion the estimates were not similar between 

hatchery and wild Chinook salmon. Hatchery Chinook salmon were recaptured at 4 times the rate of 

wild Chinook salmon in April 2008, and 10 times the rate of wild Chinook salmon in June 2009. Roper 

and Scarneccia (1996) found that hatchery age-0 Chinook salmon were captured with far less efficiency 

than wild Chinook salmon, the opposite of our finding. Ricker (1975) suggests that one assumption 

when testing trap efficiency is that the test groups should have similar behavior. Similar capture rates 

among species or age classes would be unlikely because different species exhibit different migratory 

behavior (Quinn, 2005). Therefore, we did not combine coho salmon or steelhead in our Chinook 

salmon efficiency estimates. To show the range in the number of Chinook salmon being produced in the 

White Salmon River, we calculated escapement of Chinook salmon using wild and hatchery Chinook 

salmon efficiency estimates (table 6). Because of our inconsistent efficiency estimates for age-1 fish, we 

do not believe that this information should be used to estimate total escapement for age-1 fish of any 

species. 

There was likely high temporal variability in trap efficiency over multiple time scales due to 

rapidly changing White Salmon River flow from dam operations as well as weather events and snow 

melt, and due to the influence of a rapidly changing Bonneville pool elevation (fig. 2). The river width 

and depth and water velocity at the trap site varied unpredictably due to the interaction between 

Bonneville and Condit dam operations. This affected the spin rate of the rotary trap and likely affected 

fish behavior and trap efficiency. Therefore, an expanded effort to estimate trap efficiency would be 

needed to accurately calculate escapement, and we recommend that the trap be placed above potential 

Bonneville pool influence. 

Steelhead were the most common fish collected when electrofishing the margins of the White 

Salmon River downstream of Condit Dam at all three sites sampled. Coho salmon were regularly 

captured, and in 2008 at our lower site (rkm 1.5), they outnumbered steelhead. At rkm 1.5, much of the 

habitat was shallow and had smaller substrate and slower water velocity than the other sites. Chinook 

salmon comprised only 4 percent of the catch while electrofishing, with most (95 percent) of them 

captured at rkm 2.3. Because our electrofishing sampling was in the late summer, we would expect that 

fall Chinook salmon would have already migrated out of the area. 

11
The results from this study helped guide the fish salvage and reintroduction plans in the White 

Salmon River during and after the removal of Condit Dam. The White Salmon River Working Group 

was formed in February 2007 to share information and identify and prioritize the salvage and 

reintroduction efforts for each native salmonid species. This was done in anticipation of the restoration 

of fish passage after dam removal. The group consisted of representatives from USGS, USFWS, 

Yakama Nation, PacifiCorp, National Marine Fisheries Service, Washington Department of Fish and 

Wildlife, and the U.S. Forest Service. Because of the high number of tule Chinook salmon fry found in 

this study, the group decided that there was a wild spawning population worth salvaging in the year of 

removal. A salvage effort is planned because the sediment released from the reservoir upstream of 

Condit Dam will likely smother all redds, resulting in the loss of that year’s Chinook salmon 

production. 

Several other rivers in the Pacific Northwest have large dams that are scheduled for removal or 

have recently been removed. The methods for dam removal and the strategy for dealing with the 

sediment retained behind it typically are unique to each structure (Magirl and others, 2010). The 

biological response after dam removal also likely will be unique to each river and removal method 

(Heinz Center, 2002). Dams on the Rogue River, Oregon (Savage Rapids Dam removed in 2009), 

Sandy River, Oregon (Marmot Dam removed in 2007), and Trout Creek of the Wind River, Washington 

(Hemlock Dam removed in 2009) all had fish passage, so the fish reintroduction questions are not 

similar to the White Salmon and Elwha Rivers. The Elwha River has two dams scheduled for removal 

beginning in 2011, and similar to Condit Dam on the White Salmon River, these dams have blocked fish 

for a century. However, the methods for removal and sediment management are quite different, with 

progressive notching and sediment stabilization over several years proposed in the Elwha River and 

rapid sluicing of the sediment proposed in the White Salmon River (Magirl and others, 2010). Much 

work has been conducted on the Elwha River to characterize the sediment, riparian, and aquatic 

community upstream and downstream of the dams along with efforts to predict the changes after 

removal (Duda and others, 2008). The removal of dams on the Elwha and White Salmon Rivers provide 

an opportunity to learn about fish response to newly available habitat. These dam removals provide an 

opportunity to learn about short-term response of fish to a large disturbance (dam removal). The 

removals also provide an opportunity to learn about the long-term response of fish to the redistribution 

of sediments, nutrients, wood, and aquatic communities after a century of blockage. 

We expect the species composition, migration timing, and length frequencies of anadromous 

species to change after the removal of Condit Dam, currently scheduled for October 2011. The 

historically accessible habitats will likely have a higher diversity of temperatures and feeding 

opportunities than what was available downstream of Condit Dam. As spring Chinook salmon, fall 

Chinook salmon, coho salmon, steelhead, lamprey, and possibly chum salmon recolonize their historical 

habitat, there will likely be a change in the number and size of the juveniles of those species. It was our 

intent that the electrofishing and rotary trapping results from this project provide a baseline of 

information, which can be contrasted with information collected after the dam is removed and 

anadromous fish return to their historical habitats. 

12
Acknowledgments 

Many people provided assistance to make this project a success. We would like to thank the 

USGS field crew, Jodi Charrier, Jessica Fisher, Ian Jezorek, Kyle Martens, and Carrie Munz for help 

with trap installation, data collection, and data entry. Thanks to USGS’s Western Fisheries Research 

Center (especially Steve Reuben and Reginald Reisenbichler) for loaning the 5 ft screw trap. Rod Engle 

of the USFWS was instrumental in assisting with the project design, installation, and operation. Larry 

Marchant of Spring Creek NFH provided invaluable assistance with the project design and 

implementation, as well as personnel to assist with daily trap operation. Mark Aherns, Chris Hankin, 

Casey Risley, Mark Doulos, Doug Olson, Dave Hand, Jeff Hogle, Marshall Barrows, and several other 

USFWS staff assisted in trap installation and data collection. Joe Zendt and Jeanette Burkhardt with the 

Yakama Nation fisheries staff assisted by providing some equipment, and assistance with trap 

operations. Ken Lujan, and Susan Gutenberger of the USFWS’s Lower Columbia River Fish Health 

Center provided the fish health profiles. Thanks to Keith Hatch of the Bureau of Indian Affairs for 

allowing us to use the Underwood and White Salmon in-lieu boat launches. 

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for Yakama Nation, Toppenish, Washington. 

Chapman, D.G., 1951, Some properties of the hypergeometric distribution with applications to 

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Duda, J.J., Freilich, J.E., and Schreiner, E.G., 2008, Baseline studies in the Elwha River system prior to 

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management strategies associated with dam removal in the state of Washington: in Bernard, J.M., and 

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Hydrologic Modeling, Las Vegas, Nevada, June 28–July 1, 2010, p. 1-10. 

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http://www.nwppc.org/fw/subbasinplanning/bigwhitesalmon/plan/. 

13
Pastor, S.M., 2004, An evaluation of freshwater recoveries of fish released from national fish hatcheries 

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J.G., and MacKinlay, D.D., eds., Propagated fish in resource management: American Fisheries 

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Quinn, T.P., 2005, The behavior and ecology of Pacific salmon and trout: Seattle, University of 

Washington Press, 378 p. 

Ricker, W.E., 1975, Computation and interpretation of biological statistics of fish populations: Bulletin 

of the Fisheries Research Board of Canada No. 191, 382 p. 

Roper, B., and Scarnecchia, D.L., 1996, A comparison of trap efficiencies for wild and hatchery age 0 

Chinook salmon: North American Journal of Fisheries Management, v. 16, p. 214-217. 

Schwarz, C.J., and Taylor, C.G., 1998, Use of the stratified-Petersen estimator in fisheries management: 

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14
15

Figure 1. Map of the lower White Salmon River highlighting the location where the rotary screw trap was installed 

from March through June 2006–09, and the location of efficiency releases upstream of the trap at river kilometer 

(rkm) 2.3. The sites at rkm 1.5, 2.3, and 4.2 were electrofished in the late summer 2006–09. 

Columbia River

Rotary trap location and

electrofishing site (rkm 1.5)

Electrofishing site (rkm 4.2)

0 1 2

km

N

Washington

49 W

46 W

117 W

124 W

Condit Dam

Efficiency test release site and

electrofishing site (rkm 2.3)
3/1/2006 4/1/2006 5/1/2006 6/1/2006 

White Salmon River Flow (ft

3

/s

)

800

1000120014001600180020002200240026002800

Bonneville Pool Level (ft)

7274767880

3/1/2007 4/1/2007 5/1/2007 

White Salmon River Flow (ft

3

/s)

800

1000120014001600180020002200240026002800

3/1/2008 4/1/2008 5/1/2008 6/1/2008 

White Salmon River Flow (ft

3

/s)

800

1000120014001600180020002200240026002800

Bonneville Pool Level (ft)

7274767880

3/1/2009 4/1/2009 5/1/2009 

White Salmon River Flow (ft

3

/s)

800

1000120014001600180020002200240026002800

2006 20072008 2009

Underwood Gage Stevenson Gage

Figure 2. Daily average White salmon River flow (ft3/s) during the period of trap operation from USGS gage number 141235

and Bonneville Pool level (ft above sea level) measured at USGS gage number 14128600 at river kilometer 244 of the Colu

16
Age-0 Chinook salmon

Ordinal Week

10 12 14 16 18 20 22 24 26

Average fish per day

0

100

200

300

400

500

600

700

2006

2007

2008

2009

 n n n n n n n n 

Figure 3. Average number of age-0 Chinook salmon (not including hatchery released fish) captured per day by 

the rotary screw trap for each year of operation at river kilometer 1.5 of the White Salmon River, Washington, 

March–June, 2006-09. n, not sampled. 

17
Age-1 or older Chinook salmon

Ordinal week

10 12 14 16 18 20 22 24 26

Average fish per day

0.0

0.2

0.4

0.6

0.8

1.0

2006

2007

2008

2009

 n000 n000 n00 0000 00 0 00 0 0 0000 0000 0000 0 0 n n0 n 00 n 00 n 00 n 00 nn0n 

Figure 4. Average number of age-1 or older Chinook salmon captured per day by the rotary screw trap for each 

year of operation at river kilometer 1.5 of the White Salmon River, Washington, March–June 2006–09. n, not 

sampled; 0, none captured. 

18
Age-0 steelhead

Ordinal week

10 12 14 16 18 20 22 24 26

Average fish per day

0

1

2

3

4

5

2006

2007

2008

2009

 n 00 n 00 n 00 00 00 0 00 00 0 0 0000 000 00 n n n n n 0000 n 

Figure 5. Average number of age-0 steelhead captured per day by the rotary screw trap for each year of operation 

at river kilometer 1.5 of the White Salmon River, Washington, March–June, 2006–09. n, not sampled; 0, none 

captured. 

19
Age-1 or older steelhead 

Ordinal week

10 12 14 16 18 20 22 24 26

Average fish per day

0

2

4

6

8

10

2006

2007

2008

2009

 n n n 00 0 00 0 n n n n n n0 0 nn n 

Figure 6. Average number of age-1 or older steelhead (not including hatchery fish) captured per day by the rotary 

screw trap for each year of operation at river kilometer 1.5 of the White Salmon River, Washington, March–June, 

2006–09. n, not sampled; 0, none captured. 

 

20
Age-0 coho

Ordinal week

10 12 14 16 18 20 22 24 26

Average fish per day

0

2

4

6

8

10

12

2006

2007

2008

2009

 n00 n00 n 0 0 n n0 n n n n00 nn n 

Figure 7. Average number of age-0 coho salmon captured per day by the rotary screw trap for each year of 

operation at river kilometer 1.5 of the White Salmon River, Washington, March–June 2006–09. n, not sampled; 0, 

none captured. 

21
Age-1 or older coho 

Ordinal week

10 12 14 16 18 20 22 24 26

Average fish per day

0

5

10

15

20

25

30

2006

2007

2008

2009

 n000 n000 n 00 0000 0 0 00 0 00 0 00 n0n0 n000 n000 n000 0 n000 

Figure 8. Average number of age-1 or older coho salmon captured per day by the rotary screw trap for each year 

of operation at river kilometer 1.5 of the White Salmon River, Washington, March–June 2006–09. No age-1 or 

older coho salmon were captured in 2007. n, not sampled; 0, none captured. 

22
0

5

10

15

20

25

20 30 40 50 60 70 80 90 100 110 120 130 140 150 160

Frequency

Rkm 1.5

8/25/2006

Steelhead

Coho

0

5

10

15

20

25

20 30 40 50 60 70 80 90 100 110 120 130 140 150 160

Frequency

Rkm 2.3

8/21/2006

0

5

10

15

20

25

20 30 40 50 60 70 80 90 100 110 120 130 140 150 160

Frequency

Fork Length (mm)

Rkm 4.2

8/25/2006

Figure 9. Length-frequency histograms of coho salmon and steelhead collected by electrofishing a 4.5-m swath of 

the left margin of the White Salmon River, at river kilometers (rkm) 1.5, 2.3, and 4.2, Washington, 2006. 

23
0

5

10

15

20

25

20 30 40 50 60 70 80 90 100 110 120 130 140 150 160

Frequency

Rkm 1.5

9/26/2007

Steelhead

Coho

0

5

10

15

20

25

20 30 40 50 60 70 80 90 100 110 120 130 140 150 160

Frequency

Rkm 2.3

9/25/2007

0

5

10

15

20

25

20 30 40 50 60 70 80 90 100 110 120 130 140 150 160

Frequency

Fork Length (mm)

Rkm 4.2

9/26/2007

Figure 10. Length-frequency histograms of coho salmon and steelhead collected by electrofishing a 4.5-m swath 

of the left margin of the White Salmon River at river kilometers (rkm) 1.5, 2.3, and 4.2, Washington, 2007.

24
0

5

10

15

20

25

20 30 40 50 60 70 80 90 100 110 120 130 140 150 160

Frequency

Rkm 1.5

9/5/2008

Steelhead

Coho

0

5

10

15

20

25

20 30 40 50 60 70 80 90 100 110 120 130 140 150 160

Frequency

Rkm 2.3

8/28/2008

0

5

10

15

20

25

20 30 40 50 60 70 80 90 100 110 120 130 140 150 160

Frequency

Fork Length (mm)

Rkm 4.2

9/5/2008

Figure 11. Length-frequency histograms of coho salmon and steelhead collected by electrofishing a 4.5-m swath 

of the left margin of the White Salmon River at river kilometer (rkm) 1.5, 2.3, and 4.2, Washington, 2008. 

25
0

5

10

15

20

25

20 30 40 50 60 70 80 90 100 110 120 130 140 150 160

Frequency

Rkm 1.5

8/11/2009

Steelhead

Coho

0

5

10

15

20

25

Frequency

Rkm 2.3

8/13/2009

20 30 40 50 60 70 80 90 100 110 120 130 140 150 160

0

5

10

15

20

25

20 30 40 50 60 70 80 90 100 110 120 130 140 150 160

Frequency

Fork Length (mm)

Rkm 4.2

8/11/2009

Figure 12. Length-frequency histograms of coho salmon and steelhead collected by electrofishing a 4.5-m swath 

of the left margin of the White Salmon River at river kilometer (rkm) 1.5, 2.3, and 4.2, Washington, 2009. 

26
Table 1. Weekly total number of age-0 Chinook salmon, steelhead, and coho salmon captured at the rotary screw trap at rive

White Salmon River, Washington, March–June 2006–09. [Week number indicates ordinal week with week 10 starting on March 5 of each year. Number in parenthesis indicates the number of fi

which indicates hatchery origin. NS, not sampled] 

Sampling days Chinook Steelhead 

Week 2006 2007 2008 2009 2006 2007 2008 2009 2006 2007 2008 2009 2006 

10 0 5 4 2 NS 56 428 205 NS 4 0 0 NS 11 0 6 4 4 NS 95 1,006 1,515 NS 6 0 0 NS 

12 0 7 4 4 NS 111 545 2,458 NS 5 0 0 NS 13 3 7 4 4 702 113 919 1,993(6) 0 7 0 0 18 

14 4 7 7 7 933 75 1,451(53) 1,970 1 0 0 2 21 

15 4 7 4 4 594 88 58 59 0 4 0 0 9 

16 2 7 4 4 124 68 31 70(30) 0 0 1 0 2 17 2 5 4 4 187 7 2 30 0 0 0 0 5 

18 2 1 1 1 10 1 5 0 0 0 0 0 2 

19 4 5 7 2 17 2 19 28 1 0 0 0 5 20 1 4 2 3 45 5 10 648 2 1 0 0 0 

21 0 4 0 1 NS 52 NS 21 NS 17 NS 1 NS 

22 0 3 5 4 NS 248 215 636(18) NS 2 9 13 NS 23 0 3 4 7 NS 89 155 266 NS 4 4 8 NS 24 0 4 5 4 NS 50 93(9) 78 NS 2 1 4 NS 

25 0 4 6 4 NS 10 30 9 NS 2 4 2 NS 

26 0 0 3 0 NS NS 5 NS NS NS 5 NS NS 

Sum 22 79 68 59 2,612 1,070 4,972(62) 9,986(54) 4 54 24 30 62 

27
28

Table 2. Weekly total number of age-1 or older Chinook salmon, steelhead, and coho salmon captured at the rotary screw train the White Salmon River, Washington, March–June 2006–09. [Week number indicates ordinal week with week 10 starting on March 5 of each year. Number in parenthesis indicates the number of fi

which indicates hatchery origin. NS, not sampled] 

Sampling days Chinook Steelhead 

Week 2006 2007 2008 2009 12006 2007 2008 2009 2006 2007 2008 2009 2006a 2

10 0 5 4 2 NS 0 0 0 NS 6(5) 1 0 NS 11 0 6 4 4 NS 0 0 0 NS 7(4) 2 1 NS 

12 0 7 4 4 NS 0 0 1 NS 7(4) 0 0 NS 13 3 7 4 4 0 0 0 0 0 8(2) 0 0 0 

14 4 7 7 7 0 0 1 1 3(1) 10(2) 4 2 1 15 4 7 4 4 0 1 0 0 3 20(4) 8 3 7 16 2 7 4 4 0 1 0 1 0 7 9 15 0 17 2 5 4 4 0 0 0 0 1 20 29 8 6 18 2 1 1 1 0 0 0 0 30(23) 3 33(30) 89(81) 35 

19 4 5 7 2 0 0 0 0 36(14) 61(52) 52(43) 6(2) 107 

20 1 4 2 3 0 2 1 0 2 17(15) 9(7) 4(4) 9 

21 0 4 0 1 NS 1 NS 0 NS 11(7) NS 4(2) NS 

22 0 3 5 4 NS 1 0 0 NS 10(5) 3 3(1) NS 23 0 3 4 7 NS 2 0 0 NS 4(1) 4(1) 4(2) NS 24 0 4 5 4 NS 1 0 0 NS 3(1) 1 0 NS 25 0 4 6 4 NS 2 0 0 NS 0 4(1) 0 NS 26 0 0 3 0 NS NS 0 NS NS NS 0 NS NS 

Sum 22 79 68 59 0 11 2 3 75(38) 194(102) 159(82) 139(92) 165 

1Smolting coho salmon with adipose fins present, but highly eroded anal fins (likely hatchery released) were incorrectly identified in 20

salmon. Results from genetic analysis corrected this field identification error, and the data presented are the corrected information. 
Table 3. Rotary screw trap installation date, number of days fished, and the number of genetic samples collected at 

river kilometer 1.5 of the White Salmon River, Washington, 2006–09. 

Genetic samples collected 

Year Installation date End date 

Total number of 

days fished/year Chinook Steelhead Coho 

2006 Mar 27 May 18 23 427 17 48 

2007 Mar 6 June 28 79 624 116 157 

2008 Mar 4 June 27 68 644 2 0 

2009 Mar 9 June 24 59 2 42 0 

Table 4. Total number of fish and amphibian species, other than Chinook salmon, coho salmon, and steelhead, 

caught at a rotary screw trap at river kilometer 1.5 in the White Salmon River, Washington, for each year of 

operation, March–June 2006–09. 

Total fish caught in rotary screw trap 

Species 2006 2007 2008 2009 

Lamprey (Lampetra spp.) 15 117 66 65 

Longnose dace (Rhinichthys cataractae) 3 27 9 6 

Mountain whitefish (Prosopium williamsoni) 0 3 0 1 

Northern pikeminnow (Ptychocheilus oregonensis) 0 0 0 4 

Peamouth (Mylocheilus caurinus) 0 1 0 0 

Pink salmon (Oncorhynchus gorbuscha) 1 0 0 0 

Sculpin (Cottus spp.) 6 16 12 6 

Smallmouth bass (Micropterus dolomieu) 0 0 1 0 

Largescale sucker (Catostomus macrocheilus) 1 2 2 3 

Three-spined stickleback (Gasterosteus aculeatus) 19 1 2 2 

Unknown fish 1 12 8 21 

Pacific giant salamander (Dicamptodon tenebrus) 0 2 0 0 

29
30

Table 5. Number of hatchery and wild Chinook salmon and steelhead that were released and recaptured to 

estimate trapping efficiency of a rotary screw trap at river kilometer 1.5 on the White Salmon River, Washington. 

[Rotary trap was operated for at least 12 consecutive days after all efficiency releases. All age-0 fish used for efficiency 

releases were Chinook salmon and all age-1 or older fish used for efficiency releases were steelhead] 

Age class Year Release dates Number released Number recaptured Efficiency (%) 

Hatchery Wild Hatchery Wild Hatchery Wild 

0 2006 April 4-7 -- 499 -- 3 -- 0.6 

May 9 -- 9 -- 0 -- 0.0 

2007 March 7 - April 24 -- 300 -- 4 -- 1.3 

May 7 - June 14 -- 408 -- 5 -- 1.2 

2008 April 1-5 500 532 53 13 10.6 2.4 

May 5-7 570 -- 5 -- 0.9 -- 

June 16-17 532 -- 9 -- 1.7 -- 

2009 March 31 - April 1 500 952 6 13 1.2 1.4 

April 20 500 0 30 -- 6.0 -- 

June 1 - June 4 500 312 18 1 3.6 0.3 

1 or older 2006 May 9 33 -- 2 -- 6.1 -- 

2007 March 7 - April 24 -- 61 -- 0 -- 0.0 

May 7 - June 14 -- 73 -- 0 -- 0.0 

2008 May 5-7 61 -- 0 -- 0.0 -- 

Table 6. Number of Chinook salmon captured at a rotary screw trap at river kilometer 1.5 and total escapement 

estimates of tule and upriver bright fall Chinook salmon during the days the trap operated in the White Salmon 

River, Washington. 

[Efficiency estimates used to calculate escapement were the mean from tests when more than 300 wild Chinook salmon or 

500 hatchery Chinook salmon were released upstream. n, number; URB, upriver bright] 

Escapement estimate 

Total captured Using mean wild fish efficiency Using mean hatchery fish efficiency 

Year Tule URB Tule (1.4 percent n=4) URB (0.7 percent n=2) Tule (5.9 percent n=2) URB (2.7 percent n=2) 

2006 2,550 177,586 43,220 

2007 614 456 42,760 58,991 10,407 17,208 

2008 4,445 527 309,557 68,176 75,339 19,887 

2009 8,300 1,686 578,026 218,111 140,678 63,623 
Table 7. River kilometer (rkm), year, and number of fish by species and age class (age 0 salmonids were less than 105 millim

were collected during electrofishing surveys from three sites in the White Salmon River, Washington. [No other fish species were captured while electrofishing. ≥, equal to or greater than] 

Number of fish 

Steelhead Chinook Coho Other 

Site (rkm) Year Age 0 Age≥1 Age 0 Age≥1 Age 0 Age≥1 Lamprey Sculpin Longnose dace Stic

1.5 2006 41 0 0 0 6 0 4 6 0 

2007 28 0 0 0 3 0 2 3 1 

2008 14 0 0 0 35 0 0 0 1 2009 63 0 0 0 62 0 0 0 2 

Sum 146 0 0 0 106 0 6 9 4 

2.3 2006 64 17 1 0 19 0 0 15 2 

2007 30 11 2 0 10 0 0 9 0 

2008 26 21 5 0 37 0 1 10 0 

2009 20 5 30 0 19 1 17 0 

Sum 140 54 38 0 85 0 2 51 2 

4.2 2006 97 4 0 0 2 0 0 2 0 

2007 82 5 1 0 0 0 0 0 0 

2008 66 8 1 0 11 0 0 7 0 2009 77 13 0 0 18 0 0 9 0 

Sum 322 30 2 0 31 0 0 18 0 

31
Table 8. Fish health report results from fish collected in the White Salmon River, Washington, and submitted to the 

U.S Fish and Wildlife Service’s Lower Columbia River Fish Health Center, 2006–09. 

 [Species: CHN, Chinook salmon, URB, upriver bright. Age: Juv, juvenile. Disease: ND, None detected. Comments: USGS, 

U.S. Geological Survey; USFWS, U.S. Fish and Wildlife Service. mm, millimeter] 

Date Species 

Number 

of fish 

Mean 

fork 

length 

(mm) Age Disease Comments 

4/05/2006 steelhead 1 158 Juv ND 

4/05/2006 fall CHN 4 40 Juv ND 

4/05/2006 sculpin 1 182 Adult ND 34 Chinook salmon fry in its stomach. 

5/05/2006 spring CHN 4 132 Juv ND These fish were hatchery coho salmon that 

were incorrectly identified as yearling 

Chinook salmon by USFWS and by USGS; 

highly eroded anal fins. 

8/21/2006 steelhead 1 87 Juv Epistylis Female. Fish had white patches throughout 

body surface. Epistylis (high levels) with a 

lot of mucous. 

8/21/2006 coho 1 82 Juv ND – 

3/13/2007 fall CHN 4 39 Juv ND Mortalities. Egg sack present 

3/13/2007 sculpin 1 30 Juv ND – 

3/13/2007 Pacific lamprey 1 105 Juv ND Mortality. 

3/21/2007 steelhead 1 250 Juv ND Frayed fins. Right eye missing. 

3/21/2007 fall CHN 1 40 Juv ND Mortality in trap. 

3/26/2007 sculpin 1 35 Juv ND Big female with eggs. five Chinook salmon 

fry in its stomach. 

3/28/2007 fall CHN 2 40 Juv ND – 

4/03/2007 fall CHN 2 40 Juv ND – 

4/04/2007 fall CHN 1 36 Juv ND Mortality in trap. 

4/10/2007 steelhead 1 250 Juv ND Heavy descaling. Eroded dorsal fin. 

4/11/2007 fall CHN 1 39 Juv ND – 

4/22/2007 fall CHN 1 40 Juv ND – 

4/24/2007 coho 1 35 Juv ND Mortality in trap. 

4/25/2007 coho 1 36 Juv ND Mortality in trap. 

5/09/2007 coho 1 38 Juv ND Mortality in trap. 

9/26/2007 steelhead 1 70 Juv ND – 

9/26/2007 steelhead 2 71, 

unknown 

Juv ND – 

3/11/2008 sculpin 1 152 Adult ND Big female with eggs. 21 fall Chinook 

salmon fry in stomach. 

4/08/2008 sculpin 1 168 Adult ND Big female with eggs. 14 fall Chinook 

salmon fry in stomach. 

4/01/2009 fall CHN (Tule) 30 38 Juv ND Fish appeared to be in good health. 

4/07/2009 fall CHN (Tule) 30 40 Juv ND Fish appeared to be in good health. 

5/19/2009 fall CHN (URB) 30 40 Juv ND Fish appeared to be in good health. 

6/02/2009 fall CHN (URB) 30 40 Juv ND Fish appeared to be in good health. 

32
Publishing support provided by the U.S. Geological Survey

Publishing Network, Tacoma Publishing Service Center

For more information concerning the research in this report, contact the 

 Director, Western Fisheries Research Center

 U.S. Geological Survey

 6505 NE 65th Street

 Seattle, Washington 98115

http://wfrc.usgs.gov/
Allen and Connolly—Composition and Relative Abundance of Fish Species in the Lower White Salmon River, Washington, Prior to the Removal of Condit Dam—Open-File Report 2011-1087