Bull Trout (Salvelinus confluentus) Population and Habitat Surveys in the Middle Fork Willamette and McKenzie River Systems

Amy M. Ambrosier, Stephen D. Hammond and Giles C. Thelen

Oregon Department of Fish and Wildlife Springfield, OR 97478

November 30, 1995 CONTENTS Page ABSTRACT...... 1 INTRODUCTION...... 1 DESCRIPTION OF PROJECT AREA ...... 2 METHODS ...... 3 Distribution Surveys...... 3 Transplants...... 5 Genetic Sampling ...... 5 Spawning Surveys ...... 5 Redd Characterization ...... 6 Creel Surveys ...... 6 RESULTS...... 7 Mainstem McKenzie Population...... 7 Anderson Creek Downstream Migrant Trap ...... 7 Juvenile Transfers ...... 8 Distribution Surveys...... 9 Standard Hole Counts ...... 9 Spawning Surveys...... 10 Genetic Sampling ...... 12 Trail Bridge Reservoir Population ...... 12 Juvenile Transfers ...... 12 Distribution Surveys...... 12 Spawning Surveys...... 13 South Fork McKenzie Population...... 13 Distribution Surveys...... 13 Standard Hole Counts ...... 13 Spawning Surveys...... 14 Genetic Sampling ...... 14 Middle Fork Willamette Population ...... 14 DISCUSSION AND CONCLUSIONS ...... 15 Mainstem McKenzie Population...... 15 Trail Bridge Reservoir Population ...... 16 South Fork McKenzie Population...... 17 Middle Fork Willamette Population ...... 17 ACKNOWLEDGMENTS...... 18 REFERENCES...... 19 APPENDIX A Water velocity, depth, substrate and cover types over bull trout redds in Anderson Creek , 1994 ...... 21 FIGURES and TABLES Page Figure 1. Length frequency histogram for juvenile bull trout captured in a downstream migratory trap from February through September 1995. ... 8 Figure 2. Bull trout observed during snorkel surveys of eight standard pools in the McKenzie River, 1994...... 9 Figure 3. Bull trout observed during snorkel surveys of eight standard pools in the McKenzie River, 1995...... 10 Figure 4. Number of bull trout observed during snorkel surveys of 15 pools on the South Fork McKenzie, 1995...... 14

Table 1. Table 1. The capture of bull trout fry and juveniles in the downstream ..... 7 migrant trap on Anderson Creek, 1994-1995...... Table 2. Anderson Creek redds cumulative totals, 1995...... 10 Table 3. Anderson Creek redds in index area, 1989-1995...... 11 ABSTRACT

Populations of bull trout (Salvelinus confluentus) in the McKenzie and Middle Fork Willamette River basins were studied to determine their relative abundance, distribution, and habitat requirements. The bull trout population in the Upper McKenzie system appeared to be the largest and fastest growing population surveyed. In one day, up to 33 adults were observed in eight pools in the mainstem of the Upper McKenzie. The number of redds in Anderson Creek, which is believed to provide the majority of spawning habitat in the Upper McKenzie system, continues to increase. Redds were also observed in Olallie Creek, upstream of Highway 126, after the installation of a fish passage culvert. Bull trout fry, transferred to sections of Sweetwater Creek and Olallie Creek above two fish passage culverts, were observed one to three years later near their release sites and appeared healthy. The trend of the bull trout population in the South Fork McKenzie is unknown. In 1995 up to 17 adult bull trout were sighted in one day where only three adults were observed in 1994. Roaring River is the only tributary on the South Fork McKenzie in which bull trout redds and juveniles have been located. It is believed to be the major spawning tributary above Cougar Reservoir. Despite recent, unverified sightings by anglers, no bull trout were located on the Middle fork Willamette River.

INTRODUCTION

In 1980, the American Fisheries Society designated bull trout (Salvelinus confluentus) a distinct species from dolly varden (S. malma). Bull trout are large predators weighing up to fifteen pounds. Historically they were held in low regard due to their piscivorous nature. Anglers and resource managers implemented eradication efforts, blaming bull trout for contributing to declines in populations of more desirable species such as Pacific salmon (Oncorhynchus spp), rainbow trout (O. mykiss), and cutthroat trout (O. clarki). Bull trout are now thought of as a valuable indicator of the status and health of an ecosystem. This is because they require very cold spring fed water, high quality pristine habitat (usually associated with old growth forests), and unrestricted interbasin migrations (Ratliff and Howell 1992). Listing under the Endangered Species Act was recently judged to be warranted but was precluded by higher priority species and limited resources.

Bull trout are extinct in Oregon from all areas west of the Cascades except the McKenzie drainage and possibly the Middle Fork Willamette drainage. Bull trout in the McKenzie River basin were either a contiguous population from the lower McKenzie River to Tamolitch Falls or two populations with some overlapping distributions. If two populations did exist, one spawned in the upper reaches of the South Fork and one in the upper reaches of the mainstem. The South Fork population was cut off from the mainstem McKenzie in 1963 by the construction of .

Historically, bull trout were reported in the Middle Fork Willamette basin in the Middle Fork and North Fork Willamette Rivers as well as Salt, Swift, and Staley Creeks.. This

1 population was isolated in 1961 by Hills Creek Dam and has since declined. Chemical treatment to remove non-game fish above the dam, habitat alteration from road construction and timber harvests, loss of juvenile spring chinook as a food source, and mortality from angling all may have contributed to the decline of this population. The last confirmed sighting was a photograph taken by an angler in 1990.

The objectives of this study are to determine the status of bull trout populations in the McKenzie and Middle Fork Willamette River basins and to ascertain how to secure healthy populations with long-term sustainability. This study is funded by the Bonneville Power Administration. It began in June 1994 and will continue through November 1998. Substantial contributions of funds and personnel were made by the Willamette National Forest, Eugene Water and Electric board, Oregon Department of Transportation, Oregon Council of the Federation of Fly Fishers, and Trout Unlimited.

DESCRIPTION OF PROJECT AREA

The project area includes the South Fork McKenzie River above Cougar Reservoir, the McKenzie River above McKenzie Bridge, and the Middle Fork Willamette River above Hills Creek Reservoir.

McKenzie River Basin: The McKenzie River basin drains an area of approximately 1,300 square miles from the crest of the Cascades to the Willamette River. The mainstem of the McKenzie River originates at Clear Lake, 90 river miles (RM) from the mouth. The principal upper tributaries include Lost and Horse creeks, South Fork McKenzie River, and Blue River. The average annual precipitation ranges from 40- 50in. near Springfield to 100-110in. at the headwaters. Much of the basin is mountainous with steep gradients, particularly in the upper reaches.

South Fork McKenzie River, Horse Creek, Lost Creek, and the upper portion of the mainstem McKenzie River above Belknap Springs (RM 75), originate in the High Cascades Province. The remaining area of the upper McKenzie and South Fork McKenzie rivers lies within the Western Cascades Province.. Douglas-fir, hemlock, and western red cedar are the dominant tree species. Cottonwood, red alder, and bigleaf maple are common along stream channels.

Six dams have been constructed on the McKenzie River and its tributaries, primarily for hydroelectric generation and flood control. Except for Leaburg Dam, the dams have blocked nearly all downstream and all upstream movement of fish, inundating rearing areas of trout and other resident species.

Cougar and Blue River dams have altered natural flow and temperature patterns below the dams from spring through fall. Changes in the McKenzie River are moderated by mainstem flow from above the confluence of Blue River and the South Fork. The combined effect of both projects on the flow of the McKenzie River has been a 30 to

2 50% reduction in February through June flows and similar increases in August through October flows. Mainstem temperatures downstream to Leaburg Dam average about 1.2°C lower from June through early September and 1.2°C higher from mid-September through November (Morse et al. 1987).

Timber production is the dominant economic activity. Increasing outdoor recreation is also important to the local economy.. During the 1983 trout season an estimated 54,000 anglers fished the McKenzie River between Blue River and Armitage Park. An additional 36,000 nonangling boaters used that same section of the river. Reservoirs in the basin also support these activities.

Middle Fork Willamette River Basin: The headwaters of the Middle Fork Willamette River are near Timpanogas Lake at the crest of the Cascade mountains. The Middle Fork Willamette flows northwesterly for 84 miles before joining with the Coast Fork of the Willamette to form the Willamette River. Annual precipitation averages 40 inches at Oakridge and more than 70 inches in the High Cascades.

The topography is characterized by steep ridges and narrow valleys typical of the west slope of the Cascades. Soils tend to be unstable and fine textured with a high clay content. Mass landslides from the steep slopes and pervasive surface erosion contribute substantial sediment and turbidity to downstream areas.

Riparian zones vary widely in size and vegetative complexity as a result of the many permutations of elevation, topography, stream gradient, soil, stream width, and various land use practices. Common tree species include black cottonwood, red alder, bigleaf maple, Douglas fir, western red cedar, and mountain hemlock. Riparian areas contain diverse shrub species including vine maple, willow, salal, and huckleberries. Medium to high stream gradients as well as cool water temperatures provide excellent salmonid habitat.

Forestry is the most common land use practiced in the basin. Many tributary watersheds in the Middle Fork Willamette River basin have been extensively logged.

METHODS

Distribution Surveys

Juveniles: Sections of stream identified as probable juvenile habitat were surveyed. Small shallow streams with low water velocity as well as areas in larger streams that provided ample cover were snorkeled. Areas too shallow to effectively snorkel were surveyed from above the water. Some areas were also sampled with a backpack electrofisher. Notes were kept on numbers, lengths, and species of fish as well as habitat characteristics. Trail Bridge Reservoir was surveyed at night using SCUBA to

3 determine the distribution and abundance of bull trout and to ascertain bull trout utilization of conifers placed near Sweetwater Creek in 1994.

Areas surveyed for juvenile bull trout included: Mainstem McKenzie population • Anderson Creek downstream of Highway 126 and from FR 830 crossing downstream 1,000m • Olallie Creek downstream of highway 126 • Creek 58 • Separation Creek from the mouth up 1,800m and a 600m section of Separation Creek in the near Harvey Creek • Harvey Creek • Deer Creek, including an artificial side channel • Buck Side Channel, a side channel of the mainstem McKenzie River just downstream of Deer Creek • George Creek; visual survey only • Johnson Creek at the confluence with the Leaburg canal

Trail Bridge Reservoir population • Bunchgrass Creek from the confluence of Smith River upstream 750m • Trail Bridge Reservoir

South Fork McKenzie population • South Fork McKenzie from Roaring River to 3 km above the South Fork trail • Elk Creek, a 450m section in the wilderness area • Roaring River from the confluence with the South Fork to 750m above the Roaring River Campground and two short sections near mile post 23 of FR. 19 • , a 1000m section about 3.8 km above the mouth

Middle Fork Willamette population • Beaver Creek from FR. 21 down to the mouth • Found Creek from the confluence up to the Middle Fork Willamette River Trail • Indigo Creek • Chuckle Springs • Pioneer Gulch from the mouth to FR 21 • Swift Creek from the mouth upstream 1,200m and a 350 meters sections near Bear and Moss Creeks • Warfield Creek from the FR 23 crossing to Hills Creek • Hills Creek from the confluence of Warfield Creek to FR 5875 bridge crossing • Salmon Creek from FR 2408 bridge crossing upstream 3.1 km, and just below Salmon Creek Falls • North Fork Middle Fork Willamette River

4 Adults: Adults were defined as any bull trout with a fork length longer than eight inches. Surveys were conducted by snorkeling and by frequent counts in standard pools. These surveys were done during the day because visibility is better and adult bull trout are usually dispersed along the bottoms of pools. Eight pools on the mainstem McKenzie River from Olallie Campground down to Paradise Campground were surveyed 10 times in both 1994 and 1995. The South Fork McKenzie River was snorkeled from the Three Sisters Wilderness boundary to Cougar Reservoir to locate standard pool sites. A series of 15 pools from just above Roaring River to Cougar Reservoir were surveyed nine times each. On the Middle Fork Willamette, several 1000m sections were snorkeled and spot checks were conducted in the deeper pools between Beaver Creek and the Hills Creek Reservoir.

Bull Trout Transplants

A rotary screw downstream migrant trap was placed in Anderson Creek just below the Highway 126 culvert. Numbers and timing of migrating fry and juvenile bull trout were documented during the spring of 1993, 1994, and 1995. A portion of the fish captured were transported to Sweetwater and Olallie Creeks and released. Surveys to determine the abundance and distribution of these fish began at the release sites and continued downstream 150m on Sweetwater Creek and downstream 600m on Olallie Creek.

Genetic Sampling

Tissue samples of bull trout were collected from Anderson Creek using the rotary screw trap, from Roaring River using electrofishing, from a rotary screw trap in South Fork McKenzie one mile above Cougar Reservoir, and with a trap net in Cougar Reservoir. These samples were transferred to ODFW Research for DNA analysis.

Spawning Surveys

Bright, well-defined redds were counted and marked with ribbon by surveyors walking along the creek. Adult fish were also noted.Anderson Creek was surveyed from the confluence with the McKenzie River to a falls 2.4 miles upstream. Eight surveys were conducted on Anderson Creek from September 14 through October 18 in 1994. In 1995 surveys began August 22 and were conducted weekly through October 16. Olallie Creek was surveyed from the mouth upstream to the culvert at Highway 126 in 1994. In 1995 surveys were conducted from the mouth to the springs on both the south and north forks. Spawning surveys were conducted between Trail Bridge Dam and Tamolitch Falls on the McKenzie River, from the mouth to Stringer Bridge on Sweetwater Creek, and from Smith Reservoir to the mouth on the Smith River. The South Fork McKenzie River was surveyed from RM 22, just downstream of Roaring River, to a migration barrier just past RM 29 in the Three Sisters Wilderness. Roaring

5 River was surveyed 2.5 miles from the mouth upstream past the confluence of McBee Creek. A survey was conducted on Augusta Creek from the mouth to an impassable falls 1.9 miles upstream. The lower .3 miles of Rebel Creek were also surveyed.

Probable spawning areas on the Middle Fork Willamette as well as Swift, Simpson, and Found Creeks were surveyed weekly during the 1994 spawning season but not in 1995.

Redd Characterization

Bull trout redds were surveyed by measuring water velocity, redd size, depth, and by recording cover, substrate, and distictive attributes. Water velocities over the redds were measured in Anderson Creek using a Marsh-McBirney Flo-Mate digital flow meter. To calculate the average velocities the 0.2, 0.4, 0.8 of depth method was used as described by Marsh-McBirney, Inc. (1990). Water velocities at three positions depths; over the tailout, the right side facing upstream (side one), and the left side facing upstream (side two), were measured. These depths were determined by multiplying the total depth by 0.2, 0.4, and 0.8. At each of these three positions, the point velocities were measured and recorded using a fixed point average time of ten seconds. To obtain the final mean velocities, the 0.2 and 0.8 velocities were averaged, and that result averaged with the 0.4 velocities.. The 0.4 measurement was used to calculate velocity at the head of each redd.. The total width of each redd was measured at the widest point, and the length was measured from the head downstream to the end of the tailout.. Substrate composition and cover were recorded using methods described by Hardin-Davis, Inc. et al. (1991).

Creel Surveys

Occasionally, anglers and campers were interviewed concerning their catch. This information was recorded and entered into a data base.

6 RESULTS

Mainstem McKenzie Population

Anderson Creek Downstream Migrant Trap

A total of 1,877 bull trout fry were captured by the downstream migrant trap in Anderson Creek from February 15 to May 31, 1995. It was estimated that 3,597 bull trout fry would have been captured if the trap had been continuously operating. This is similar to the number captured in 1994 (Table 1).

A total of 306 bull trout juveniles age 1+ and older were captured in the Anderson Creek trap in 1995. It was estimated that 1,094 bull trout juveniles would have been captured from February 15 through August 31, 1995 if the trap had been operating continuously. In 1994 130 juveniles were caught with a possible catch of 267 in March and April (Table 1). April through August does not represent the entire downstream migration period in Anderson Creek; bull trout were still being captured at the end of the sampling period.

Table 1. The number of bull trout fry and juveniles age 1+ and older caught in the downstream migrant trap on Anderson Creek, 1994-1995 Number of fry Number of age 1+ and older bull trout

Date Captured If trap ran continuously Captured If trap ran continuously

Feb. 15 - 1808 3185 129 242 Apr. 26, 1994

Feb. 15 - 1877 3597a 261 471b May 31, 1995 a The estimated total through April 26 was 3,255. b The estimated total through April 26 was 240.

There appeared to be two distinct bull trout migrations. One was comprised of 70 to 90 mm fish which included both age 1+ and 2+ fish. Age 1+ and older juveniles captured in the downstream migrant trap during the spring and summer months were 30 mm to 60 mm larger than similar age classes captured in late winter (Figure 1). No bull trout over 120 mm were caught, indicating that these fish have probably migrated out of this system. The second migration was comprised of fry, generally less than 30 mm,

7 migrating in the early spring. By late summer the young of the year range in size from 30 to 50 mm.

Figure 1. Length frequency histogram of bull trout captured in a downstream migrant trap in Anderson Creek during 1995. Bull trout less than 40 mm captured from February through May were rarely measured (1,877 fry were captured in this time period).

Juvenile Transfers

Juvenile bull trout were transferred from Anderson Creek to Olallie Creek in 1994 and 1995 to speed up the colonization of habitat above Highway 126. This area had been inaccessible to bull trout migrating from the McKenzie River since the Highway was constructed in the early 1960s. The number of juveniles transferred were as follows:

Year Number of fry transferred

1994 245 1995 313

In 1994, 23 of the age 0 bull trout released in the North Fork Olallie Creek were observed. The fish were mainly distributed in several pools near the release site and

8 became increasingly sparse downstream. A total of 300m were surveyed, however, no bull trout were observed more then 60m downstream from the release site.

Distribution Surveys

A 180 mm bull trout was found in lower Separation Creek, a tributary to Horse Creek. Fish in this system identified as bull trout in 1993 were probably spring chinook. No bull trout were found in upper Separation Creek, Harvey Creek, George Creek, Johnson Creek 58, or Buck Side Channel.

Standard Hole Counts

In 1994, 32 adult bull trout were observed during snorkel surveys of eight standard pools on the upper McKenzie River. The same pools were surveyed in 1995 and 33 adults were identified. The adults appeared to be staging in the large pools below Anderson and Olallie Creeks prior to spawning. Concentrations of adult bull trout were in pools further downstream early in the season and moved upstream as the numbers increased (Figures 2 and 3).

15

10

5

0

07/07

Number of Bull Trout 07/27 Ollalie 08/23 Deer Cr. 09/07 09/15 Highway 09/22 Ledge Date 09/27 U. Belknap 10/07 10/20 L. Belknap 11/10 Fish Rock Paradise

Figure 2. Number of bull trout observed during snorkel surveys of eight standard pools of the McKenzie River, 1994..

9 15

10

5

0 06/20 06/27 Ollalie 07/06

Number of Bull Trout Deer Cr. 07/18 Highway 07/31 08/09 Ledge Date 08/23 U. Belknap 08/29 09/06 L. Belknap 10/25 Fish Rock Paradise

Figure 3. Number of bull trout observed during snorkel surveys of eight standard pools of the McKenzie River, 1995..

Spawning Surveys

The only known spawning areas of the upper McKenzie River bull trout population are Anderson and Olallie creeks. No bull trout redds were found during surveys of Separation Creek or Lost Creek. Weekly counts of bull trout redds in Anderson Creek are shown in Table 2. Spawning began in early September, peaked in late September, and was completed by mid October.

Table 2. Anderson Creek redd counts, 1995. Date Below Culvert Above culvert Total

08/22/95 0 0 0 08/28/95 0 0 0 09/05/95 0 2 2 09/12/95 1 7 8 09/20/95 2 21 23 09/26/95 0 32 32 10/03/95 0 9 9 10/10/95 0 2 2 10/16/95 0 0 0 TOTAL 3 74 77

Previous surveys of Anderson Creek stopped at RM 1.6. This study was extended up to a falls at RM 2.4 in order to include the entire area of Anderson Creek accessible to

10 bull trout. No redds were observed above the falls. The number of redds in the index area on Anderson Creek has been increasing since 1989 (Table 3).

Table 3. Bull trout redds counted in Anderson Creek in the USFS index area and total area counts by ODFW, 1989-1995. Number of redds observed Index area Total area survey Year (to RM 1.6) (to RM 2.4) 1989 7 1990 9 1991 7 1992 13 1993 15 1994 22 30 1995 30 74

In 1994, three redds were counted in Olallie Creek between the confluence with the McKenzie River and Highway 126. Two adults were observed on one of the redds. Spawning habitat is limited in this area by high water velocities. In 1995, a culvert was placed under the highway allowing bull trout access to high quality spawning and rearing habitat above the highway for the first time in 35 years. 10 redds were observed in Olallie Creek. Only one was located below Highway 126.The other nine were found upstream, including six in the North Fork of Olallie Creek.

Of the 30 redds documented in 1994 in Anderson Creek, depths and water velocities were measured for 28 (See Appendix A). The average depth and velocity on side one were 0.773 feet and 0.288 meters/second respectively; and 0.745 ft, 0.264 meters/second on side two. At the head the average depth was .952 ft, ranging between .6 and 1.5 ft. The mean velocity was .296meters/second. The tailspill average depth and velocity were .49 ft and .493meters/second, respectively. The primary substrate was small to medium gravel and some redds contained large gravel and small cobble.

11 Genetic sampling

Tissue samples from 30 bull trout were collected at the downstream migrant trap in Anderson Creek. The samples were transferred to ODFW Research who sent them to the University of Montana for analysis.

Trail Bridge Reservoir Population

Juvenile Transfers

Bull trout fry were transferred to Sweetwater Creek in 1993, 1994, and 1995 to seed spawning and rearing habitat made available by the installation of a fish passage culvert under Highway 126. Number of bull trout transfered were as follows:

Year Number of fry transferred 1993 308 1994 507 1995 589

In 1993, twelve age 0+ bull trout from the transfer were observed in Sweetwater Creek.

All of the eighteen bull trout observed in 1994 were within 50m of the release site. Seven age 0+ bull trout were observed at the release site in the mossy margins. Eleven age 1+ fish were found dispersed throughout the 50m, intermingling and feeding with similar size cutthroat trout.

In June of 1995, snorkel surveys identified twenty-one age 0+, twelve age 1+, and seven age 2+ bull trout. Mostly older fish were found in the lower portion of the stream and younger fish up higher.

Distribution Surveys

Four 150-200mm bull trout as well as a large number of brook trout were observed during a night SCUBA survey of Trail Bridge Reservoir in 1995. The bundles of conifers placed in the reservoir near Sweetwater Creek were not being utilized.

No bull trout were found in Bunchgrass Creek.

12 Spawning Surveys

No redds were observed between Kink Creek and Trail Bridge Reservoir in 1994. In 1995, seven redds were located in the McKenzie River between Kink Creek and Trail Bridge Reservoir. Some of these redds were thought to be from bull trout. No redds were found in Smith River or Sweetwater Creek.

South Fork McKenzie Population

Distribution Surveys

Juvenile bull trout were observed in Roaring River below Roaring River Campground while snorkeling in 1994 and 1995. Nineteen were caught by electrofishing in 1995 between the mouth and the campground. One juvenile was observed in the South Fork near Homestead Campground in 1994. Snorkel surveys of Elk and French Pete Creeks failed to locate any bull trout. A 10 inch bull trout was captured in the downstream migrant trap.

Standard Hole Counts

There was a large difference in the number of bull trout seen when snorkeling in the South Fork McKenzie in 1994 and the number seen in 1995. A total of only three adult bull trout were observed all year in 1994 during surveys of 14 pools between the Roaring River confluence and Cougar Reservoir. In 1995, 17 bull trout were observed in one day, thirteen of which were found in a pool at the Dutch Oven Campground (Figure 4).

13 15

10

5 Creek Hole Roaring R. Dutch Oven 0 Triple Rock 06/21 07/13 M.P. 45 07/20 07/27

Number of Bull Trout 08/03 French Pete 08/10 08/24 08/31 10/31 Trap Hole Date

Figure 4. Number of bull trout observed during snorkel surveys of 15 pools on the South Fork McKenzie, 1995.

Spawning Surveys

In 1994, one potential redd was observed in the Roaring River, approximately 50 meters from the mouth. In 1995, two redds were located near the Roaring River Campground. Extensive surveys of the upper South Fork and several of its tributaries failed to locate other redds.

Genetic Sampling

A total of 21 samples were collected from the South Fork population; 19 from Roaring River, 1 from the downstream migrant trap about a mile above the reservoir, and one in a trap net at the head of the reservoir. Because of their small size 7, of the Roaring River fish were killed. The samples were transferred to ODFW Research.

Middle Fork Willamette Population

No bull trout or bull trout redds were found in the Middle Fork Willamette basin in 1994 or 1995. Indigo and Chuckle springs appeared ideal for rearing with good cover and woody debris but lacked gravel for spawning. Anglers reported several bull trout caught

14 from the Middle Fork Willamette River around Indigo Springs and Swift Creek but no confirmation was provided.

DISCUSSION AND CONCLUSIONS

This discussion and conclusions section is incomplete as Oregon Department of Fish and Wildlife has not yet completed its research.

After surveying both days and nights, it became evident that bull trout tend to be more acitve and visible at night.

Mainstem McKenzie Population

The population of bull trout in the McKenzie River appears to be the largest and most secure in the upper Willamette Basin. Key spawning and rearing areas have been identified and are relatively protected. The number of adults in this population appears to be increasing. This is due in part to angling regulations adopted in 1990 that require the release of bull trout. A large increase in the bull trout population of the Metolius River was noted after implementation of similar regulations a decade earlier (Ratliff, 1992). The increasing number of redds in both Anderson and Olallie Creeks implies that the spawning population has been increasing since 1989. Our counts in eight standard pools on the mainstem showed no apparent increase from 1994 to 1995. Counts on the Metolious River showed the same trend of increased redds after implementation of angling restrictions. With the increase in spawning bull trout and very limited area for rearing in Anderson Creek, the numbers of redds may level off within the next few years.

The number of adults per redd has been reported as 2 (Pratt, 1985) to 3.2 (Fraley and Shepard, 1988). Based on these figures and the number of redds counted, we estimate that 154 to 246 bull trout spawned in Anderson Creek in 1995. Measurements and conditions of the redds in were similar to those found by Reiser et al (1994), demonstrating consistency in choice of spawning habitat and redd location. With the increase of spawning adults, we expect to see a carrying capacity of rearing areas met and therefore a higher number of juveniles migrating out of the stream within the next few years. This may lead to an increase of sub-adults in the tributaries along the McKenzie River and perhaps the discovery of new spawning habitat. Surveys have shown fairly consistent numbers of both fry and juvenile bull trout during the past three years of monitoring. Figure 8 shows a 1994 peak in potential out migration of juveniles which implies that more fish are moving downstream. These downstream migrant fish are likely looking for available rearing areas, including the stretch below the trap and the mainstem McKenzie River. Possiblealternative tributaries with spawning habitat include Lost, Horse and Deer creeks.

15 Bull trout redds in Anderson Creek have increased over the past several years, potentially leading to an increase of fry in the creek and in the downstream migrant trap. Based upon conservative estimates, each adult female lays an average 2,500 eggs (Bell 1986) and 20% survive to emergence (Pratt 1992), thus predicting an increase of at least 3,500 fry. From 1994 to 1995 our trap data indicated similar numbers of fry (3,194 in 1994 to 3,147 in 1995 [Figure 7]). This shows that there is either an increase in mortality or an increase in habitat utilization. If rearing areas are at carrying capacity, then fry are likely being preyed upon. The lack of increase of potential juveniles could also be due to other factors which may become more apparent at the conclusion of this study.

The increase of redds in Anderson Creek should result in at least 20,000 fry in the system in the spring of 1996. A significant increase in the number of migrating fry should be observed with consistent monitoring of the trap in the spring. The mainstem McKenzie should be surveyed in the area surrounding the mouth to determine if bull trout fry and juveniles are utilizing this habitat. To determine the carrying capacity of juvenile bull trout in the channel, estimates of population density versus age class will have to be made. The population densities are currently calculated using USFS data of 19 bull trout observed in a 120m section below the culvert. There are approximately 3600m to the falls at the upper limit of juvenile bull trout rearing. Expanding USFS data to the entire system, there are at least 570 juvenile bull trout, 60% of which are 1+ year olds. This number is extremely conservative because snorkeling counts of juveniles tend to underestimate their numbers (USFS, 1989). Furthermore, the habitat is notably variable throughout this system.

Trail Bridge Reservoir Population

The bull trout transferred to Sweetwater Creek above Trail Bridge Reservoir appear to be doing well. The discovery of three age classes in the creek is very interesting. In Anderson Creek, age 2+ bull trout began to descend in the spring and moved into the mainstem McKenzie River by late summer. Larger numbers of older bull trout remained in Sweetwater Creek than in Anderson Creek. This area may have optimal foraging, thereby encouraging these fish to stay . The older fish in the system are entirely piscivorous and are a potential threat to young fry. Larger numbers of fry should be transplanted elsewhere in order to counter the increase of predation. Transplanted bull trout should be placed near the headwaters to help avoid contact with older fish.

Brook trout in Trail Bridge Reservoir may compete with bull trout. Both spawn in the fall leading to competition for space and prime spawning gravel. No hybrids were observed, however, if brook trout and bull trout were to mate, the result might be sterile hybrids (Williams et al. 1989). In the future, more frequent spawning surveys should be conducted to determine timing of redds and to observe spawning.

16 Transport of bull trout fry to Sweetwater Creek should continue until a population is established

South Fork McKenzie Population

The current assessment of the South Fork McKenzie bull trout population is that it is slowly increasing and will continue to do so. It is presumed that past harvest has limited the number of older fish in this population. Snorkel surveys indicated an increasing number of mature adults staging in the river. This increased number has not yet coincided with an increase in the number of redds as would be predicted. Only two redds and a low number of juveniles were observed in Roaring River, the primary nursery stream. Radio telemetry may be necessary to locate prime spawning and rearing areas in this system because the passed methods have been inconclusive.

A screw trap was placed in the South Fork McKenzie River during the summer to capture fish migrating downstream. We missed the ideal spring migration of bull trout fry and juveniles to the reservoir, and so feel that our capture data is not representative or a valuable indication of the juveniles in the basin.

The South Fork population should implement a radio tracking program with consistent monitoring of the population.

Middle Fork Willamette Population

Information collected so far during this study suggests that the population in the Middle Fork Willamette may be extinct. Snorkeling and spawning surveys failed to located any bull trout. The last confirmed sighting was a photograph of a fish caught in Hills Creek Reservoir in 1990. A working group comprised of representatives from ODFW, USFS, USACE, Eugene Water and Electric Board (EWEB), Weyerhaeuser, and Fly Fishing Federation has been assembled. This group will draft a recovery plan for bull trout in the Willamette Basin.

Future sampling efforts should continue in order to confirm the status of this population. Sampling should include trap netting in Hills Creek Reservoir, snorkeling in mainstem areas to look for adults, electrofishing possible juvenile rearing areas, and spawning ground surveys.

17 ACKNOWLEDGMENTS

We would like to thank the Bonneville Power Administration for funding this on going study, Dave Bickford and Jim Capurso of the US Forest Service for assisting us with numerous projects on the McKenzie, and our supervisors Mark Wade and Jeff Ziller for all their teaching, guidance, and assistance. Also, thank you to Sandra Lewis who did field work for the study in July, 1994 before accepting a position in graduate school.

18 REFERENCES

Bell, Milo C. 1986. Fisheries Handbook of engineering requirements and biological criteria. US Army Corps of Engineers, Portland, Oregon.

Brown, L. G. 1992. Draft management guide for the bull trout on the Wenatchee National Forest. Washington Department of Fish and Wildlife, Wenatchee. 49pp.

Cavander, T. M. 1978. Taxonomy and distribution of the bull trout, Salvelinus confluentus (Suckly), from the American northwest. California Fish and Game 3:139-174.

Fraley and Shepard 1988. Life history, ecology, and population status of migratory bull trout, (Salvelinus confluentus) in the Flathead Lake and River system, Montana. (Draft). Montana Department of Fish, Wildlife, and Parks, Kalispell, Montana. in Goetz, F. 1989. Biology of the bull trout, Salvelinus confluentus, a literature review. U.S.D.A., Willamette National Forest, Eugene, Oregon.

Hardin-Davis, Inc., Harza Northwest, Inc., and Clearwater Biostudies, Inc. 1991. Habitat suitability criteria for salmonids of the McKenzie River. Prepared for Eugene Water and Electric Board, Eugene, OR. 31pp.

Marsh-McBirney, Inc. 1990. Flo-mate model 2000 portable water flowmeter instruction manual. Fredrick, MD. 17pp.

Pratt, K., 1984. Habitat use and species interactions of juvenile cuthtroat and bull trout in the upper Flathead River Basin. M.S. Thesis. University of Idaho, Moscow, Idaho.

Pratt, K., 1985. Pend Orielle trout and char life history study. Idaho Department of Fish and Game in Goetz, F. 1989. Biology of the bull trout, Salvelinus confluentus, a literature review. U.S.D.A., Willamette National Forest, Eugene, Oregon.

Pratt, K., 1992. A review of bull trout life history. Pages 5-9 in Howell, P.J. and D.V. Buchanan, editors. Proceedings of the Gearhart Mountain bull trout workshop. Oregon Chapter of the American Fisheries Society, Corvallis.

Ratliff, D. E. and P. J. Howell. 1992. The status of bull trout populations in Oregon. Pages 10-17 in P. J. Howell and D.V. Buchanan, editors. Proceedings of the Gearhart Mountain bull trout workshop. Oregon Chapter of the American Fisheries Society, Corvallis.

19 Ratliff, D. E. 1992. Bull trout investigations in the Metolius River-Lake Billy Chinook system. Pages 37-44 in P. J. Howell and D.V. Buchanan, editors. Proceedings of the Gearhart Mountain bull trout workshop. Oregon Chapter of the American Fisheries Society, Corvallis.

Reiser, D., and four co-authors. 1994. An evaluation of spawning habitat used by bull trout in the Cedar River watershed, Washington, USA.

Rieman, B. E. and J. D. McIntyre. 1993. Demographic and habitat requirements for conservation of bull trout. US Forest Service, Intermountain Research Station, Ogden, UT 40pp.

Willamette National Forest. 1989. Biology of the bull trout. Eugene, OR. 52pp.

Williams, J. E. and seven co-authors. 1989. Fish of North America, endangered, threatened, or of special concern. Fisheries. 14(6): 2-20.

20 APPENDIX A

Water velocity, depth, substrate and cover types over bull trout redds in Anderson Creek Oregon, 1994

MEAN COLUMN VELOCITY (m/s) TOTAL DEPTH (ft) Side 1 Side 2 Tailspill AVERAGE VELOCITY (m/s) Marked Width Length Side 1 Side 2 Focal Tailspill .2~~.8~~.4 .2~~.8~~.4 .2~~.8~~.4 Side 1 Side 2 Tailspill Focal SUBSTRATE COVER redd # (in) (in) (.4 ft) 3 0.7 0.8 0.8 0.4 .18; .37; .29 .1; .22; .21 .43; .49; .45 0.283 0.185 0.455 0.31 34.6 0 4 0.8 1 1.2 0.15 .03; .1; .08 .09; .23; .18 .45; .54; .44 0.073 0.17 0.468 0.13 54.7 0 5 0.7 0.8 1 0.45 .23* .26; .22 .47* .52; .51 .53* .81; .54* 0.233 0.503 0.605 0.2 53.6 4 6 0.75 0.7 0.8 0.4 .22; .31; .28 .01* .27; .07* .36; .4; .33; 0.273 0.105 0.355 0.24 32.8 5 7 0.75 0.5 1 0.4 .46* .55; .51 .37* .39; .2 .51* .58; .5* 0.508 0.29 0.523 0.3 54.7 0 8 0.5 0.9 0.9 0.55 .33* .4; .35 .13; .34; .19 .23* .31; .19 0.358 0.213 0.23 0.46 46.7 2 9 1.3 1.2 1.5 1 .21; .43; .37 .33; .44; .34 .72; .7; .62 0.345 0.363 0.665 0.26 34.6 1-4 10 0.9 0.9 1 0.6 .26; .6; .34 .21; .44; .37 .68* .82; .75 0.385 0.348 0.75 0.49 45.4 0 2A 0.8 0.5 0.9 0.25 .41; .4; .46 .04* .15; .02 .39* .37; .37 0.433 0.058 0.375 0.26 45.7 0 3A 0.9 0.9 1.1 0.55 .24; .3; .27 .2; .23; .21 .39* .49; .43 0.27 0.213 0.435 0.16 64.7 2 6A 0.7 0.9 1 0.8 .51* .6; .56 .52; .78; .67 .63* .85; .75 0.558 0.66 0.745 0.61 34.6 4, 2 8A 0.5 0.4 0.6 0.2 .02; .08; .01 .04; .07; .06 .21* .2; .17* 0.03 0.058 0.188 0.18 34.6 4 10A 0.95 1 1.2 0.8 .35; .4; .4 .18; .47; .36 .36 .48; .44 0.388 0.343 0.43 0.1 45.7 2 11A 25 40 0.8 0.7 1.2 0.7 .21* .41; .34 .41; .53; .46 .37* .49; .39 0.325 0.465 0.41 0.24 34.6 0 (4) 12A 20 47 0.8 0.8 0.9 0.8 .32* .55; .41 .41* .57; .42 .24* .51; .27 0.845 0.455 0.323 0.39 34.5 1 14A 38 54 0.5 0.7 0.85 0.3 .29; .27; .29 .05* .05; .05 .52* .53; .51* 0.285 0.05 0.52 0.13 54.6 4, 2 15A 42 65 0.7 0.5 0.9 0.15 .13* .18; .09 .13* .14; .15 .43* .43* .42* 0.1223 0.143 0.4223 0.05 46.7 0 16A 39 49 0.5 0.5 0.6 0.2 .07* .15; .11 .39* .41; .4 .61* .6* .62* 0.11 0.4 0.613 0.33 34.5 0 17A 40 46 1 0.65 1.1 0.5 .07; .36; .13 .0; .05; .0 .57; .7; .57 0.173 0.05 0.603 0.48 63.6 0 18A 35 54 1 1 1 0.9 .15; .16; .16 .09; .31; .21 .26; .49; .43 0.158 0.205 0.403 0.07 53.5 2 19A 51 64 0.9 0.7 1 0.4 .08; .12; .1 .35* .47; .43 .43* .57; .47* 0.1 0.42 0.485 0.4 36.6 0 21A 32 60 1.1 0.7 1.1 0.7 .14; .35; .27 .24* .24; .26 .7* .76; .66 0.258 0.25 0.695 0.28 54.5 0 22A 25 55 0.6 0.7 0.8 0.3 .16* .2; .16 .07* .14; .08 .31* .3* .31* 0.18 0.093 0.305 0.14 36.7 0 25A 31 53 0.5 0.5 0.6 0.4 .3* .36; .31 .11; .33; .2 .41* .61; .46* 0.32 0.21 0.485 0.33 52.5 0 26A 40 68 0.8 0.6 0.9 0.6 .4* .61; .45 .29* .46; .3 .38* .6; .38 0.478 0.338 0.435 0.45 34.7 2

21 Appendix A (continued) 27A 34 52 0.6 0.8 0.7 0.4 .06* .14; .12 0; .31; 0 .62* .67; .63* 0.11 0.31 0.638 0.3 36.6 0 (2) 29A 33 55 0.8 0.8 1 0.5 .17* .28; .24 .18* .28; .22 .53* .66; .59 0.233 0.225 0.593 0.19 54.6 0 30A 42 60 0.8 0.7 1 0.3 .14*, .33, .21 .26, .29, 27 .68*, .67, .61 0.223 0.273 0.643 0.06 54.7 0 AVERAGE 35.13 54.8 .773 .745 .952 .49 .288 .264 .493 0.296

*=water level too low for described technique for velocity measurements, so the lowest possible measurement was used. substrate composition (HaFRin-Davis et al, 1991): Each point was described by a three digit code (xx.x). The first digit represented the dominant substrate type, the second represents the sub-dominant, and the thiFR expressed the percentage of the cell occupied by the dominant type. 1 = mud, silt 2 = sand 3 = small gravel (0.1-0.5 in) 4 = Medium gravel (0.5-1.5 in) 5 = Large gravel (1.5-3.0 in) 6 = Small cobble (3-6 in) 7 = Large cobble (6-12 in) 8 = Boulder (12+ in) cover composition (HaFRin-Davis et al, 1991): 0 = no cover 1 = undercut bank 2 = overhanging vegetation 3 = boulders 4 = logs/roots

22 the potential fry are compared to the number of redds for the respective brood year observed in the index area above the culvert. The majority of the water coming out of the culvert flows into the trap, so the efficiency of the trap was estimated to be >80%.

1200 30

800 20

Fry

400 10 Redd Number of redds Estimated number of fry

0 0 1992 1993 1994 1995 Brood year Figure 7. Estimated number of fry caught in Anderson Creek in April versus parent redds in the index area upstream of the culvert, 1992-1995 brood years..

23