MIGRATION BEHAVIOR AND DISTRIBUTION OF ADULT PACIFIC
LAMPREY IN THE WILLAMETTE BASIN
Report prepared for The Columbia River Inter-Tribal Fish Commission
Prepared by:
Ian Courter1
Shadia Duery1
Jay Vaughan1
Chris Peery2
Mark Morasch1
Rebecca McCoun3
Benjamin Clemens4
Carl Schreck4
Submitted April 4, 2012
1
2
U.S. Fish and Wildlife Service Idaho Fishery Resource Office, PO Box 18 Ahsahka, Idaho 83520
3
4
Cramer Fish Sciences, 600 NW Fariss Rd., Gresham, OR 97030
Natural Resources Division, The Confederated Tribes of Grand Ronde, 47010 SW Hebo Rd.,
PO Box 10, Grand Ronde, OR 97347
Oregon Cooperative Fish and Wildlife Research Unit, Department of Fisheries and Wildlife, U. S.
Geological Survey, 104 Nash Hall Oregon State University, Corvallis, OR 97331-3803
CONTENTS Executive Summary ................................................................................................................................................................... 1 Introduction ................................................................................................................................................................................. 3 Methods .......................................................................................................................................................................................... 6 Study Area ................................................................................................................................................................................ 6 Lamprey Collection, Tagging, and Tracking .............................................................................................................. 6 Data Analysis ........................................................................................................................................................................ 10 Results .......................................................................................................................................................................................... 12 Willamette Falls Passage Timing and Tagging Distribution ............................................................................ 12 Lamprey Body Size ............................................................................................................................................................ 14 Movement and Distribution .......................................................................................................................................... 15 Active Migration and Holding .................................................................................................................................. 16 Tributary Entry .............................................................................................................................................................. 21 Discussion ................................................................................................................................................................................... 23 Acknowledgments .................................................................................................................................................................. 25 References .................................................................................................................................................................................. 26 Page i FIGURES Figure 1. Map of the Willamette River Basin showing fixed radio telemetry sites established in 2009 and 2010. ....................................................................................................................................................................................... 9 Figure 2. Cumulative percentage of Pacific lamprey passage as determined by trap collections at Willamette Falls. River discharge and temperature data provided by ODFW. ........................................... 13 Figure 3. Temporal distribution of all lamprey implanted with radio tags during 2009 and 2010. .. 14 Figure 4. Length distributions of lamprey radio tagged in 2009 and 2010 and all lamprey captured at Willamette Falls in 2010. ................................................................................................................................................ 15 Figure 5. Diurnal detections of radio tagged lamprey recorded at fixed receiver sites throughout the Willamette Basin from May 2009 through February 2010. ................................................................................. 16 Figure 6. Distribution of fish in the basin following initial migration and entering the holding phase. The two colors show if the fish was tagged in the 1st or 2nd half of the season. ........................................... 18 Figure 7. Percentage of lamprey that utilized mainstem or tributary habitats during holding. .......... 19 Figure 8. Distance traveled by radio tagged lamprey between holding and final fate. ............................ 19 Figure 9. Number of radio tagged fish detections in tributaries in relation to seven-­‐day average mainstem temperatures during 2009 and 2010. ...................................................................................................... 21 Figure 10. Distribution of fish that entered and stayed in each monitored tributary during 2009 and 2010. ............................................................................................................................................................................................. 22 TABLES Table 1. Locations of the 22 fixed radio telemetry and fish release sites in the Willamette Basin. ....... 8 Table 2. Radio tagged Pacific lamprey detected according to release location and year. ...................... 15 Page ii EXECUTIVE SUMMARY Pacific lamprey (Entosphenus tridentatus) abundance in the Pacific Northwest has declined dramatically in recent decades. Diagnosing causes of declines is difficult because of the dearth of information about lamprey biology. For example, Pacific lamprey, an anadromous fish, start their spawning migration in the early spring and reside in freshwater for approximately one year before spawning, but little is known about their behavior and distribution during migration and over-­‐
winter holding. To examine these unknowns, a multi-­‐organizational collaboration between Cramer Fish Sciences, the Confederated Tribes of the Grand Ronde, and Oregon State University resulted in a two-­‐year study of the migration behavior, distribution, and habitat use of adult Pacific lamprey in the upper Willamette Basin, Oregon. From May to August 2009 and 2010, a total of 407 lamprey were radio-­‐tagged at Willamette Falls (rkm 42.6)—the gateway to the upper Willamette Basin. Twenty-­‐two fixed radio telemetry receiver sites were installed on the main stem Willamette River and its major tributaries to track lamprey movements. Fish were also tracked by boat, plane and raft. The combined use of fixed-­‐site and mobile tracking allowed us to compile detection histories for individual fish over a broad spatial area. The majority of movement in the upper Willamette Basin occurred from mid-­‐May to mid-­‐August. Ninety-­‐three percent of Lamprey were observed in mainstem and tributary habitats during active migration, traveling 0-­‐48 km per day, with average migration speeds of 3 and 4 km per day in 2009 and 2010 respectively. A wide range of migration behaviors were observed. Some fish traveled quickly to the upper reaches of the basin, while others lingered near the release site and slowly migrated upstream. Spring movement peaked at 11°C and summer movement at 22°C; however, statistical analyses did not support our hypothesis that temperature was a strong determinant of lamprey movement patterns in the upper Willamette Basin. This observation was consistent with findings of lamprey movement in the Columbia River above Bonneville Dam. Numbers of radio-­‐tagged fish were small relative to the size of the study area and available river flow and temperature data were coarse, which may have impaired our ability to detect subtle variations in lamprey movement following changes in environmental conditions. We suspect that lamprey, much like salmon and steelhead, are proficient at modulating the physiological effects of warming river conditions by seeking thermal refugia near the mouths of tributaries and hyporheic seeps. This would explain observations that lamprey were capable of upstream movements when mainstem water surface temperatures exceeded 26°C. Although radio tagged lamprey utilized all 13 monitored tributaries, detections were most frequent in the Santiam, Coast Fork Willamette, Calapooia, Yamhill and Mollalla Rivers. Lamprey also appeared to use the main stem Willamette River extensively during winter months. From November-­‐January, fish were distributed in three groups throughout the upper Willamette River mainstem (rkm 56-­‐72, rkm 174 and rkm 258-­‐290). This observation stands in contrast to behavior of adult salmon and steelhead. These species typically use rivers like the Willamette as a migration corridor, with less extensive use of large mainstem habitats for holding. Future studies should focus on learning more about environmental constraints in the main stem Willamette River, where adult lamprey are known to reside for extended periods of time prior to spawning. Emphasis should also be placed on Pacific Page 1 lamprey use of specific subbasins, particularly the Santiam River system. The disproportionately high level of use of these key watersheds suggests that they may be critical for Pacific lamprey population persistence and likely provide the best opportunities to learn about the factors limiting lamprey production elsewhere in the Willamette Basin. Page 2 INTRODUCTION Pacific lamprey (Entosphenus tridentatus formerly Lampetra tridentata) are a prehistoric, jawless fish with an anadromous life history, which includes a larval freshwater phase (ammocoete), metamorphosis, followed by emigration to the ocean and eventual adult maturation (Close et al. 2002). Their entire life-­‐cycle can range from 6-­‐14 years. During juvenile and adult life-­‐stages, Pacific lamprey are parasitic and feed on body fluids of other marine species for 20 to 40 months before returning to freshwater to spawn (Clemens et al. 2010). It has been inferred that adults do not feed after re-­‐entering freshwater (Beamish 1980), which is typically one year prior to spawning. Returning adults begin their upstream migration in spring or early summer, overwinter while sexually maturing (Scott and Crossman 1973), spawn the following spring, and die soon thereafter (Clemens et al. 2010). Eggs typically hatch within two to three weeks of deposition. After emergence, larval lamprey burrow in silt and fine sediment substrates where they rear and feed on detritus and other organic material for 4-­‐8 years before metamorphosis (Beamish and Levings 1991; Close et al. 2002). Much like anadromous salmonids, Pacific lamprey can be found throughout the Pacific Rim, from the coasts of Japan, Alaska, British Columbia, Washington, Oregon, California, and Northern Mexico (Kostow 2002). They occur throughout the Columbia Basin from the Columbia River mouth to the lower Snake River in south-­‐central Washington (Kostow 2002). Pacific lamprey are the largest and most abundant of the dozen species of lampreys found in the Columbia Basin (Kostow 2002; Wydosky and Whitney 2003). In the early 1990s, researchers noted a decline in Pacific lamprey counts throughout the Columbia Basin (Close et al. 1995; Kostow 2002). Factors contributing to this decline are not well understood, and likely include the typical suite of impacts widely studied for other anadromous species–habitat loss, migration impediments, climate change, cyclical variation in ocean survival rates, etc. (Close et al. 1995 and Clemens et al. 2010). However, lamprey abundance does not appear to be linked directly to the same abundance cycle observed in salmon and steelhead populations, and little is known about why lamprey population fluctuations differ from other native anadromous species. In 1993, Pacific lamprey were recognized as a “species of concern” in Oregon. In 2004, the federal government was petitioned to add Pacific lamprey to its list of endangered species (USFWS 2004). The petition was denied due to the lack of long-­‐term population monitoring data and biological information. In response, tribal and federal entities began conducting research on different components of Pacific lamprey biology, and efforts are currently being made to accurately enumerate lamprey at dams throughout the Columbia Basin (USFWS 2011). The precise number of Pacific lamprey that historically returned to the Columbia Basin has not been estimated, but the Willamette River, a major tributary of the Columbia River, is known to be a significant source of lamprey production (Kostow 2002). For example, several hundred thousand lamprey were harvested annually at Willamette Falls (rkm 42.6) during the 1940’s. Recent harvest Page 3 levels have been significantly lower. However, abundance of lamprey in the Willamette Basin remains high relative to other Columbia River tributaries. The cultural importance of Pacific lamprey in the Willamette Basin led to focused efforts by Native American tribes to study lamprey biology in this region (CRITFC 2008). In 2010, the Confederated Tribes of Warm Springs started a 10 year abundance monitoring study for Willamette Basin Pacific Lamprey, and the first estimate of adult escapement was recently reported for the 2010 return year–90,000 (Baker and Graham 2011). Adult spawner distribution has also became a focal point of research because such studies are expected to be useful for identifying spawning and rearing areas, as well as any potential migration impediments, such as Willamette Falls, a natural waterfall, first altered for power production purposes in 1888, that separates the lower and upper Willamette River basin (Willamette Falls Heritage Foundation, 2011). Lamprey are able to migrate over the Falls via traditional routes of passage that require scaling the waterfall, or via the Oregon Department of Fish and Wildlife’s (ODFW) fishway, designed to facilitate year-­‐round passage of salmon and steelhead. In recent years, ladder modifications have also been made to improve passage for lamprey. Although most lamprey bound for the upper Willamette Basin migrate through the fish ladder, some still ascend the eastern side of the Falls (Mesa et al. 2009). In 2009, Portland General Electric (PGE) biologists teamed with Normandeau Associates to conduct a radio tracking study to examine lamprey passage at Willamette Falls. Researchers found that approximately 45% of radio tagged lamprey migrated over the Falls within the study period (July-­‐
August). These results are similar to rates of passage observed at Bonneville Dam–47% (Moser et al. 2002) and 50% (Keefer at al. 2009a). It is difficult to say whether this observation reveals a passage impediment because some lamprey likely overwinter downstream of Willamette Falls, which means failure to pass shortly after tagging does not directly indicate mortality, nor preclude the possibility that tagged fish passed the Falls the following spring. However, researchers generally agree that fish passage facilities designed for anadromous salmonids do not provide optimal passage conditions for Pacific lamprey (Mary Moser, National Marine Fisheries Service, personal communication 2010). Pacific lamprey are relatively poor swimmers compared with salmonids and have difficulty swimming when water velocities are high 1.5-­‐2 m/s (Mesa et al. 2003). Such conditions often exist in fish ladders designed for salmon passage. After passing natural and manmade impediments, it has been observed that lamprey tend to distribute according to their size, with larger fish traveling farther upstream in search of suitable spawning habitat (Keefer et al. 2009a; also reviewed in Clemens et al. 2010). Temperature seems to be an important environmental factor triggering adult lamprey migration timing in the mainstem Columbia River (Keefer 2009b), but whether temperature controls movement at small spatial scales is less certain. Keefer et al. (2009b) found that lamprey passed Bonneville Dam coincident with temperatures between 15 and 23 degrees; however, these authors later found that lamprey movement above Bonneville Dam was not strongly correlated to mainstem river temperature. Page 4 In 2008, the Confederated Tribes of Grand Ronde (CTGR) began a multi-­‐year radio telemetry study to evaluate lamprey distribution in the upper Willamette Basin. The following year, Cramer Fish Sciences (CFS) and Oregon State University (OSU) were contracted by the Columbia River Inter-­‐
Tribal Fish Commission (CRITFC) to conduct a parallel study. These two studies evolved into a research partnership between CTGR and CRITFC contractors, which doubled the number of radio-­‐
tagged lamprey in the collective dataset and dramatically increased the geographic scope and resolution of monitoring efforts throughout the Basin. The goal of this research was to expand the current knowledge of broad scale movement patterns and habitat selection of adult Pacific lamprey in freshwater. Key objectives included: (1) determining the locations of preferred overwinter holding and spring spawning habitats, and (2) evaluating the influence of mainstem temperature and flow conditions on lamprey distribution throughout the Willamette Basin. Page 5 METHODS STUDY AREA The Willamette River originates in the Calapooya Mountains of southwestern Oregon, and flows north from the confluence of the Middle and Coast Fork Rivers near Eugene, Oregon, covering a distance of 474 km and draining over 29,138 km2 before entering the Columbia River near the town of Vancouver, Washington (Sedell and Froggat 1984). The average yearly discharge (1973-­‐2010) of the Willamette River is 933 m3/s (USGS 2010). Historically, the Willamette Basin produced large numbers of spring Chinook (O. tshawytscha), winter steelhead (O. mykiss), and Pacific Lamprey. Numbers of naturally produced anadromous fish have declined dramatically since European settlement (Dole and Niemi 2004), and salmon and steelhead populations are now supported by large-­‐scale artificial propagation programs. Willamette Falls, a 12-­‐meter high horseshoe-­‐shaped waterfall located 42.6 km upstream from the Columbia River is a prominent feature of the Willamette River, and marks the beginning of upstream anadromous migrations into the upper Willamette Basin. LAMPREY COLLECTION, TAGGING, AND TRACKING Twenty-­‐two fixed radio telemetry receiver sites were installed, including nine sites on the mainstem Willamette River (rkm 45.1-­‐289.8) and 13 at tributary mouths. Locations of fixed radio-­‐
telemetry sites were identified from previous studies of lamprey migration behavior in the Willamette Basin (Clemens et al. 2006, Confederated Tribes of the Grand Ronde unpublished data). Each site contained a Lotek SRX 400 receiver connected to a 6-­‐ element Yagi antenna facing downstream at a 45° angle to the river. Power was supplied to receivers via solar panels or an on-­‐
site power source. All stations connected to solar panels were equipped with a set of two 12 V batteries and converters as a power back-­‐up to ensure the receivers operated continuously during power outages. From April to May of 2009, four radio receiver sites were installed on the main stem (rkm 48.3, 74, 170.6, and 259.1), and five at the mouths of major tributaries (Clackamas, Pudding, North Santiam, Long Tom Rivers, and Coast Fork). In 2010, two additional sites (rkm 140 and 210.8) were installed on the main stem near the towns of Salem and Corvallis, Oregon to close a gap in coverage identified during the 2009 field season. CTGR already maintained 11 sites, primarily located in the upper reaches of the basin, as part of their ongoing lamprey tracking investigations. These sites were also included in the study, bringing the total number of radio telemetry sites to 20 and 22 in 2009 and 2010 respectively. The lowest elevation site was located below Willamette Falls on the Clackamas River (rkm 37) to detect any potential “fallback” movement downstream of the study area. The highest elevation site was on the Coast Fork of the Willamette River (rkm 300.9) (Table 1 & Figure 1). Page 6 Collection of adult Pacific lamprey was a collaborative effort between multiple parties conducting lamprey research at Willamette Falls, including PGE, Normandeau Associates, CTGR, Confederated Tribes of Warm Springs (CTWS) and CFS. In 2009, we began surgically implanting radio tags on April 28 and deployed our last tag on July 27. The following year we started a week later on May 3 and once again ended on July 27. Lamprey were captured using an existing lamprey trap located at the top of the fishway, leg 2. The aluminum trap was secured to the side of the fishway and had a funneled entryway and perforated holding box. Lamprey were attracted to the trap because it created a velocity refuge, and the smooth metal paneling near the entrance provided better adhesion than the rough concrete wall of the fishway. The trap was set nightly, checked the following morning, and removed during the day to avoid unnecessarily trapping migrating salmonids. Funnel traps and dip nets were also used to capture lamprey inside the fish ladder. Significantly more lamprey were caught in 2010 due to the increased effort of a full time CTWS field technician stationed at Willamette Falls. Consistent with commonly used methods in the Columbia River (Moser et al, 2002a), fish ≥ 10.5 cm girth just anterior to the first dorsal fin were selected to be surgically implanted with radio tags. Each radio tag (Lotek NTC-­‐6-­‐2, 4.5 g in air, 31mm x 9mm, with a whip antenna) was uniquely coded and had a transmitter with a burst rate of 6.8 to 7.2s (2009) or 4.5 to 5.0s (2010). Battery life was expected to be ~309 d. All fish were anesthetized prior to surgery. Once under anesthesia, lamprey were placed ventral side up in a wetted, 12 cm (diameter) polyvinyl chloride (PVC) pipe/cradle with a sealed T-­‐end. A portion of the pipe was cut away to allow access to the ventral surface of the animal for surgery. Radio tags and surgical tools were sterilized in a solution of chlorahexidine, following the protocols of (Moser et al, 2002a). A 10 mm incision was made in the ventral side of the animal using a sterile scalpel. The incision was made slightly off-­‐center of the mid-­‐line that runs from the anterior to posterior of the fish, aligned directly below the anterior edge of the first dorsal fin fold. A sterile catheter was then placed inside the body cavity and pushed through the musculature and skin such that a small hole was created ~50 mm posterior to the incision. The antenna of the radio tag was guided through the catheter so that it emerged from the hole created by the catheter. The radio tag was gently inserted by hand into the intra-­‐peritoneal cavity through the initial incision. A minimum of two simple, interrupted sutures (Ethicon 18’’, 3-­‐0 coated vicryl braided suture with a FS-­‐2 cutting needle) were applied to close the incision. No antibiotic ointment was applied to the incision after the tag was inserted because rubbing any material on the wound could decrease the effectiveness of the sutures and irritate the wound (B. Williams, U. Idaho Campus Veterinarian, personal communication). Animals were held in aerated river water for at least one hour following the surgery before being released upstream of Willamette Falls. Data from fixed receiver sites were downloaded onto a laptop computer every one to two weeks starting in May 2009 and lasting until the end of June 2011. Following each receiver download, data was processed and entered into an electronic database. Page 7 Table 1. Locations of the 22 fixed radio telemetry and fish release sites in the Willamette Basin. RM 23.0 25.5 26.5 28.0 28.0 28.0 30.0 37.0 37.0 46.0 54.0 55.0 87.0 106.0 108.0 108.0 108.0 119.0 131.0 133.0 148.0 161.0 175.0 180.0 187.0 RKM 37.0 41.0 42.6 45.1 45.1 45.1 48.3 59.5 59.5 74.0 86.9 88.5 140.0 170.6 173.8 173.8 173.8 191.5 210.8 214.0 238.2 259.1 281.6 289.7 300.9 Mainstem Willamette River Jon Storm Park Willamette Falls West Linn release West Linn Rock Island Champoeg Park Evergreen Eola Buena Vista Corvallis Harrisburg WR at Eugene Tributary Clackamas Tualatin Molalla Pudding Yamhill Luckiamute Santiam NF Santiam Calapooia Mary's R Long Tom Mckenzie Coast Fork Willamette Organization CFS Release PGE Release CFS and CTGR CTGR CTGR CFS CFS CTGR CTGR CFS CFS CTGR CTGR CFS CTGR CFS CTGR CFS CFS CTGR CTGR CFS Page 8 Figure 1. Map of the Willamette River Basin showing fixed radio telemetry sites established in 2009 and 2010. Page 9 DATA ANALYSIS For quality assurance purposes, detection histories were examined and dubious radio signals were flagged using the following criteria: 1) low detection power; 2) single detection lines (including detections of fish that were not observed after being release); and 3) detection histories indicating abnormal fish movements (e.g., movement of ~100 km/d). Flagged data were examined and illogical detections were removed. Illogical detections typically failed more than one of these criteria. To analyze movements during the approximate one-­‐year of freshwater residency, we divided the migration into four phases: passage, active migration, holding, and spawning. Passage was determined by the date that fish were captured passing Willamette Falls, radio tagged, and released thereafter. Active migration accounted for the time from passage to holding. Holding was defined as the period when fish were not observed moving for at least two months, and spawning was determined by the movement of fish after holding to their final fate. Radio tag detections were used to characterize the timing and duration of each migration phase. To determine potential biotic and abiotic factors that influenced lamprey migration behavior, we examined variables such as body length, river flow, water temperature, and photoperiod. Trap counts, fish size, and passage timing at Willamette Falls were also examined to determine how fish length and passage distributions of radio tagged fish compared to the entire sample collected at Willamette Falls. Cumulative distance traveled after release, days moving, and rate of movement (km/d) were calculated. Migration distance was calculated by summing all movements during active migration until each fish began a holding phase. Multiple linear regression was used to evaluate the relationships between body size (length) and migration distance. We also included the number of days the fish moved (> 2 km), rate of movement (km/d), and release date in our regression model to test if any of these variables were related to distance traveled. Movement data from 2009 and 2010 were examined separately. The duration of individual fish movement was calculated as the number of days between the release date and the last time the fish was detected before the end of active migration in the fall. Multiple linear regression was used to test for significant relationships between fish length and the number of days it moved. In this case, the regression model included movement rate and release date as potential explanatory variables. Variables describing the river environment were compiled for 2009 and 2010 to test for relationships between the proportion of fish moving each day and environmental variables in a logistic regression model. We evaluated the impact of daily river temperature, flow, and photoperiod. The proportion of fish moving each day was calculated by dividing the number of fish detected by the number of fish available to be detected within the study area. The number of fish available for detection changed throughout the migration period as more fish were tagged and Page 10 released back into the river. To account for spatial variability in river flow and temperature conditions, we divided the basin into three reaches. Reach 1 extended from rkm 42.6 to 127 (above Willamette Falls to before Salem), Reach 2 from rkm 128 to 214 (Salem to Corvallis), and Reach 3 from rkm 215 to 300 (past Corvallis to Eugene). Representative temperature and flow values were used for each section, expressed as a 7-­‐day rolling average. A rolling average was used because it seemed unreasonable to expect that lamprey would respond instantaneously to small daily incremental changes, but would more likely be influenced by a progressive change over several days. Only one value was used for photoperiod since this was not expected to vary significantly between the three reaches. Page 11 RESULTS WILLAMETTE FALLS PASSAGE TIMING AND TAGGING DISTRIBUTION Lamprey migration in the Willamette River began during late April when water temperatures at Willamette Falls reached 11°C and ended by mid-­‐August as water temperatures approached 22°C (Figure 2). Before water temperatures reached 15°C, relatively few lamprey had passed above the Falls–17% and 16% in 2009 and 2010 respectively. When river temperatures reached 17°C, 21% and 71% of migrating lamprey had passed the Falls, and at 19°C, 23% and 74% of lamprey had passed the Falls in 2009 and 2010, respectively. When water temperatures exceeded 21°C, approximately 80% of migrating lamprey had passed the Falls in both study years. Though less pronounced, river flow also appeared to affect passage at the Falls. For example, the spike in flow from 24,000 to 84,000 cfs in early June 2010 is probably responsible for the large number of fish that passed upstream during and shortly after the high flow event (Figure 2). This may explain why a high proportion of fish were observed migrating above the Falls in 2010 when water temperatures were still relatively cool. Using total trap counts as a relative abundance estimate to compare with the number and timing of tagged fish, we verified that tagging effort was roughly consistent with the weekly changes in lamprey passage frequency. Weeks with higher passage rates typically corresponded with greater numbers of tags released. We also verified release of radio tagged lamprey throughout the entire migration during both study years (Figure 3). Page 12 Passage 2010 Passage 2009 Temp 2010 Temp 2009 25 20 0.6 15 0.4 10 0.2 0 4/1 5 0 5/1 5/31 6/30 7/30 8/29 1 Cumulative percentage of passage Temp °C 0.8 30 0.8 100 Passage 2010 Passage 2009 Discharge 2010 Discharge 2009 80 0.6 60 0.4 40 0.2 20 0 4/1 Discharge cfs (000) Cumulative percentage of passage 1 0 5/1 5/31 6/30 7/30 8/29 Figure 2. Cumulative percentage of Pacific lamprey passage as determined by trap collections at Willamette Falls. River discharge and temperature data provided by ODFW. Page 13 40 2009 n=202 Number of radio tagged Oish 35 2010 n=206 30 25 20 15 10 5 0 28-­‐Apr 13-­‐May 31-­‐May 12-­‐Jun 23-­‐Jun Tagging date 6-­‐Jul 19-­‐Jul Figure 3. Temporal distribution of all lamprey implanted with radio tags during 2009 and 2010. LAMPREY BODY SIZE The length and weight distributions of lamprey selected for radio tagging were very similar over the two years of study. This was expected because fish had to have a minimum girth of 10.5 cm to prevent post-­‐tagging mortality or abnormal swimming behavior. In 2009, the mean length of radio tagged fish was 63 cm and ranged from 52 cm up to 76 cm. In 2010, mean length was also 63 cm, but the range was wider—measuring from 37 cm up to 72 cm. Mean weight was 448 g in 2009 and 439 g in 2010. It should be noted that length distributions of radio tagged fish are not representative of the entire adult lamprey population because fish were high-­‐graded for radio tagging purposes. We used 2010 length data collected by CTWS for all fish trapped at the Falls as a comparison for fish radio tagged in 2010. It was clear that the sample of radio tagged fish represented the larger size classes in the upper Willamette Basin population (Figure 4). Page 14 100 2009 radio tagged 2010 radio tagged 2010 captured 90 Frequency 80 70 60 50 40 30 20 10 0 46-­‐48 52-­‐54 58-­‐60 64-­‐66 70-­‐72 Length (cm) Figure 4. Length distributions of lamprey radio tagged in 2009 and 2010 and all lamprey captured at Willamette Falls in 2010. MOVEMENT AND DISTRIBUTION By the end of the study (June 2011), greater than 90% of fish tagged in 2009 and 2010 had been detected by one of the three methods of tracking (boat, plane, and fixed receivers) (Table 2). The majority of fish were detected by fixed radio telemetry receivers. As time at large increased, the probability of detection decreased. Based on the timing of tag detections, it was evident that lamprey move primarily between dusk and dawn (Figure 5). Table 2. Radio tagged Pacific lamprey detected according to release location and year. Above the Falls Below the Falls 2009 2010 2009 Tags deployed 149 219 145 Tags detected 138 206 63 Percent detected 93% 94% 43% Page 15 140
120
Fish Detections
100
80
60
40
20
0
0:00
2:00
4:00
6:00
8:00
10:00
12:00
14:00
16:00
18:00
20:00
22:00
Time
Figure 5. Diurnal detections of radio tagged lamprey recorded at fixed receiver sites throughout the Willamette Basin from May 2009 through February 2010. ACTIVE MIGRATION AND HOLDING Patterns of movement during active migration were examined in 2009 and 2010. The average distance traveled by tagged lamprey in 2009 was 86 km and did not differ significantly between the first and second portion of the active migration period (82-­‐93 km). In 2010, the average distance lamprey traveled increased significantly to 119 km, and did not vary between the first (116 km) and second (124 km) portion of the active migration period. Forty-­‐one percent of fish tagged in 2009 traveled less than 50 km before holding, compared to only 20% of fish in 2010 (Figure 6). Fish tagged in 2010, a high flow year, distributed more evenly throughout the basin. Lamprey that migrate over the Falls earlier in the season tended to distribute more evenly in the basin, whereas fish tagged during summer months (June – July) did not travel to the uppermost reaches of the basin (Figure 6). The duration of active migration was significantly different between the first and second portions of the active migration period. The number of days lamprey moved before holding decreased through the season in both 2009 and 2010. In 2009, tagged lamprey moved for an average of 70 days, but Page 16 fish in the first half of the migration moved an average of 90 days, while fish entering the system later moved an average of 60 days. In 2010, a similar trend was observed–the average time spent moving for all lamprey was 64 days, with fish tagged early in the migration moving an average of 73 days, while fish tagged latter only moved an average of 55 days. Figure 7 shows that the majority of the tagged Pacific lamprey used the mainstem to hold during the winter. In both years of the study, the active migration phase accounted for the bulk of the total migration distance. The spatial distribution at holding and final fate of tagged lamprey was very similar, indicating that lamprey typically did not move large distances after holding (Figure 8). Page 17 2009 300-­‐350 spring, n=88 Mainstem Rkm 250-­‐300 summer, n=104 200-­‐250 150-­‐200 100-­‐150 50-­‐100 0-­‐50 0% 5% 10% 15% 20% 25% 30% 35% 40% 45% 2010 300-­‐350 spring, n=88 250-­‐300 summer, n=117 Mainstem Rkm 200-­‐250 150-­‐200 100-­‐150 50-­‐100 0-­‐50 0% 10% 20% 30% 40% 50% Figure 6. Distribution of fish in the basin following initial migration and entering the holding phase. The two colors show if the fish was tagged in the 1st or 2nd half of the season. Page 18 2009 n=192 2010 n=205 100% 84% 78% Percent of Oish 80% 60% 40% 22% 16% 20% 0% Main Stem Tributary Main Stem 2009 Tributary 2010 Location at holding Figure 7. Percentage of lamprey that utilized mainstem or tributary habitats during holding. 70% 2009 n=74 60% Percent of Fish 2010 n=117 50% 40% 30% 20% 10% 0% Distance (km) Figure 8. Distance traveled by radio tagged lamprey between holding and final fate. Page 19 Regression analyses results show cumulative distance traveled in 2009 was significantly related to overall length (p < 0.001), the number of days moving (p < 0.001), kilometers traveled per day (p < 0.001) and release date (p = 0.02). Distance traveled increased for larger lamprey that spent more days moving and moved at a faster rate. Cumulative distance decreased for lamprey that entered the system later in the run. Results from the same analysis using the 2010 movement data showed similar relationships with length (p < 0.001), number of days moving (p = 0.002) and release date (p = 0.04). In 2010, increases in length and number of days moving were associated with greater distance traveled, while fish traveled shorter distances as the season progressed. Results from the analyses examining relationships between the number of days lamprey were migrating and biological parameters were consistent between both years of tracking data. Kilometers traveled per day and release date were both negatively correlated with the number of days the fish moved. As described earlier, the number of days moving decreased significantly as the season progressed (2009: p = 0.001, 2010: p < 0.001). The speed at which the fish traveled was also negatively associated with the number of days moving (2009: p < 0.001, 2010: p < 0.001). We investigated the effects of environmental variables on general movement patterns observed over the two years of tagging. Several variables, including flow, temperature, and photoperiod, were included in a logistic regression analysis to test for effects on movement patterns. No significant relationships between the proportion of fish moving and any of the environmental variables were detected. Page 20 TRIBUTARY ENTRY Adult lamprey were detected entering tributaries throughout both study years. During spring tributary use peaked when mainstem temperatures were between 12-­‐14 °C and in the summer between 18-­‐20 °C (Figure 9). Tributary use was lower during 2009 (14%) compared to 2010 (28%). Mainstem Reach 1 tributaries had the most use; however, the largest percentage of fish that were observed entering and staying in tributaries chose tributaries in Reach 2 (66%), with fewer residing in Reach 1 (26%) and Reach 3 (7%) tributaries. Figure 10 shows the distribution of fish that were observed entering and remaining in monitored tributaries. During both study years, the Santiam River was the preferred watershed. Fish Detections in Tributaries 60 50 Reach 1, n=108 Reach 2, n=72 40 Reach 3, n=11 30 20 10 0 2-­‐4 4-­‐6 6-­‐8 8-­‐10 10-­‐12 12-­‐14 14-­‐16 16-­‐18 18-­‐20 20-­‐22 Mainstem Temperature °C Figure 9. Number of radio tagged fish detections in tributaries in relation to seven-­day average mainstem temperatures during 2009 and 2010. Page 21 Clackamas R 5% 2010 n=67 1% 2% TualaLn R 2009 n=57 13% 11% Molalla R 1% Pudding R 5% 10% 12% Yamhill R SanLam R 58% 35% 4% 4% Luckiamute R 3% Calapooia R Mary's R 9% 5% 1% 2% Long Tom R 4% 4% Mckenzie R 1% MF WillameBe R Coast Fork WillameBe R 7% 0% 10% 20% 30% 40% 50% Percent of fish that entered to stay in tributary 60% 70% Figure 10. Distribution of fish that entered and stayed in each monitored tributary during 2009 and 2010. Page 22 DISCUSSION During our two-­‐year study of Pacific lamprey migration behavior and distribution in the upper Willamette Basin, we monitored 407 adult lamprey. Movements occurred during the crepuscular and nighttime period, confirming observations of Hardisty and Potter (1971), Robinson and Bayer (2005), and McIlraith and Caudill (2010), who also found that adult Pacific lamprey migrate primarily between dusk and dawn. We classified Willamette Basin Pacific lamprey adult migration into four phases: passage, active migration, holding, and spawning. Passage above Willamette Falls into the upper basin appeared to be modulated by water temperature conditions, and the proportion of migrating fish passing the Falls at specific river temperatures corresponded extremely well with observations in the Columbia River at Bonneville Dam. Keefer et al. (2009a) and Mesa et al. (2009) reported that few lamprey passed Bonneville Dam before water temperatures reached 15°C, while about half of the migration passed before water temperatures reached 19°C, and 80% of the run had passed before water temperatures reached 21-­‐23°C. This is nearly identical to what we observed during our study with the exception that a large number of fish passed Willamette Falls in 2010 between 15-­‐17°C, likely because of a corresponding high flow event. Whereas water temperature increases appear to provide a cue to initiate migration into the upper Willamette Basin, we found no significant relationship between “active migration” movements and river temperature, river flow, or photoperiod. Pacific lamprey studies in the Columbia (Keefer et al. 2009b) and Snake Rivers (McIlraith and Caudill 2010) also yielded similar results. McIlraith and Caudill (2010) noted that even a 10°C difference in water temperature between two rivers—the Snake and Clearwater—did not appear to significantly impact lamprey distribution. This and other studies suggest that although lamprey may be responding to environmental cues like flow and temperature to begin their freshwater migrations, these covariates are poor predictors of smaller scale movements and distribution patterns. One possible explanation for these seemingly contradictory findings is that lamprey are able to tolerate warming river conditions by seeking thermal refugia near the mouths of tributaries and hyporheic seeps, thereby making it possible for them to avoid stressful temperature regimes. These types of behaviors are common in other anadromous species (e.g. Berman and Quinn 1991). The average distance traveled during active migration was 86 km in 2009 and 119 km in 2010, and it was apparent that fish entering the basin later traveled faster upstream. Similar to Keefer et al. (2009a), we also observed that cumulative distance traveled was positively correlated with overall fish length, indicating that larger fish typically migrated further upstream. Lamprey active migration in the Willamette River ends by mid-­‐October, around the same time observed in the Snake River (McIlraith and Caudill 2010), but slightly later than in the John Day River, OR (Robinson and Bayer 2005). Page 23 After tagging, lamprey were observed distributing throughout the upper Willamette Basin, actively migrating upstream to overwinter holding locations, often in the main stem Willamette River, in close proximity to eventual spawning tributaries. Distribution was not effected by release date, and the distances traveled during active migration were similar for fish entering the basin in the spring and those entering in the summer. However, the number of days fish were observed moving decreased as the season progressed, suggesting that later arriving fish traveled faster once past Willamette Falls. In the John Day River it was also observed that fish migrating to overwintering habitats late in the migration season (August) exhibited shorter travel times than fish migrating earlier (Robinson and Bayer 2005). Contrary to conventional wisdom that Pacific lamprey enter tributaries primarily for spawning in the spring, we observed them entering tributaries throughout the year, often traveling between mainstem and tributary habitats numerous times before spawning. In particular, the Santiam River system was used extensively by lamprey throughout the study period. We hypothesize that the Santiam River is chosen because it maintains relatively high flows compared to other tributaries of the Willamette, providing lamprey holding habitat while they complete sexual maturation. Another plausible hypothesis is that this site provides better temperature conditions for juveniles and adults because the Santiam River was on average 2-­‐3 °C cooler than mainstem Willamette River temperatures from May through September 2009 and 2010. Mesa et al. (2003) found that holding behavior had a minimal effect on energy reserves, suggesting that energy expenditures are greatest during active migration. Similar to Keefer et al. (2009a), we found that a very small percentage of tagged fish moved long distances after overwintering. Taken together, these studies could suggest that movement of individual lamprey during the active migration period is directed toward a specific location and occurs at the rate necessary to arrive at the intended location before energetic costs of active migration become prohibitive. Adult lamprey are known to select spawning sites based on presence of larval pheromones (Waldman et al. 2008), so it is reasonable to assume that adult lamprey move quickly to areas in close proximity to rearing juveniles before beginning the “holding” phase of their spawning migration. It should be noted that our data represented the larger size classes of lamprey in the upper Willamette Basin. Due to limitations imposed by the size of the radio tags, we were unable to tag fish with a girth less than 10.5 cm. This constrained our sample to fish ranging from 37-­‐76 cm in length and 439-­‐448 g in mean weight. Keefer et al. (2009a) found that the larger fish in the Columbia River were last observed in upstream reaches. Similarly, the majority of fish in our study were last observed in the middle and upper reaches of the upper Willamette Basin. It is probable that a representative sampling of the entire population would reveal a clear size stratification, with larger fish spawning further upstream and smaller fish spawning in lower elevation tributaries. On the other hand, Pacific lamprey body size decreases with maturity prior to spawning (Clemens et al. 2009), which may imply that the majority of lamprey we tagged were sexually immature. This would bias our sample towards fish natal to the upper reaches of the watershed. A rigorous study of the relationship between body size and spawning elevation would likely require that fish tagging and tracking occur near the mouth of the Willamette River, or in the Lower Columbia River. Page 24 In general, Pacific lamprey behavior and movement patterns observed in the upper Willamette River basin aligned well with results from lamprey migration studies conducted in the Columbia and Snake Rivers. Future studies should focus on learning more about environmental constraints in the main stem Willamette River, where adult lamprey are known to reside for extended periods of time prior to spawning. Emphasis should also be placed on Pacific lamprey use of specific subbasins, specifically the Santiam River system. The disproportionately high level of use of these key watersheds suggests that they may be critical for Pacific lamprey population persistence and likely provide the best opportunities to learn about the factors limiting lamprey production elsewhere in the Willamette Basin. ACKNOWLEDGMENTS This project was funded by the Columbia River Inter-­‐Tribal Fish Commission (CRITFC) and a grant from the U.S. Fish and Wildlife Service. Brian McIlraith and Bob Heinith were points of contact at CRITFC. Their support and review of our work is greatly appreciated. Dr. Paul Anders also provided significant contributions via technical review of our written report. We thank Carson McVay, CTWS for his work capturing and handling lamprey at Willamette Falls in 2010. Lastly, we thank our numerous colleagues who supported this project through providing technical support, equipment use, and peer review, including staff at Normandeu Associates, PGE, CTWS, and CFS. Page 25 REFERENCES Baker, C., and Graham, J. 2011. Willamette Falls Lamprey Escapement Estimate. Annual Report to BPA. Confederated Tribes of Warm Springs Reservation Oregon. Branch of Natural Resources Fisheries Research. Beamish, R. J. 1980. Adult biology of the river lamprey (Lampetra ayersi) and the Pacific lamprey (Lampetra tridentata) from the Pacific coast of Canada. Canadian Journal of Fisheries and Aquatic Sciences 37:1906-­‐1923. Beamish, R.J., and C.D. Levings. 1991. Abundance and freshwater migrations of the anadromous parasitic lamprey, Lampetra tridentata, in a tributary of the Fraser River, British Columbia. Can. J.
Fish. Aquat. Sci. 48:1250-1263.
Beamish, R.J., and C.D. Levings. 1991. Abundance and freshwater migrations of the anadromous parasitic lamprey, Lampetra tridentata, in a tributary of the Fraser River, British Columbia. Can. J.
Fish. Aquat. Sci. 48:1250-1263.
Berman, C.H. and T. P. Quinn. 1991. Behavioural thermoregulation and homing by spring chinook salmon, Oncorhynchus tshawytscha (Walbaum), in the Yakima River. Journal of Fish Biology 39: 301–312.
Clemens, B. J., Binder, T. B., Docker, M. F., Moser, M. L., and Sower, S. A. 2010. Similarities,
differences, and unknowns in biology and management of three parasitic lampreys of North America.
Fisheries. 35:12: 580-594
Clemens, B. J., S. J. van de Wetering, J. Kaufman, R. A. Holt, and C. B. Schreck. 2009. Do summer
temperatures trigger spring maturation in adult Pacific lamprey, Entosphenus tridentatus? Ecology of
Freshwater Fish 18:418-426.
Clemens, B.J., R.J. Magie, D.A. Young, M.G Mesa, H.W. Li and C.B. Schreck. 2006. Aerial tracking of
Pacific lamprey in the Willamette Basin, Oregon. Report to the U.S. Bureau of Reclamation.
Portland, Oregon.
Close, D.A., M. Fitzpatrick, H.W. Li. 1995. Oregon Cooperative Fishery Research Unit, Department of
Fisheries and Wildlife, Oregon State University, Blaine Parker, Douglas Hatch, Columbia River
Inter-Tribal Fish Commission, Gary James, Department of Natural Resources, Fisheries Program,
Confederated Tribes of the Umatilla Indian Reservation, U. S. Department of Energy, Bonneville
Power Administration, Division of Fish and Wildlife, Project Number 94-026, Contract Number
95BI39067, 40 electronic pages (BPA Report DOE/BP-39067-1)
Close, D.A., M.S. Fitzpatrick, 2002. The ecological and cultural importance of a species at risk of extinction, Pacific lamprey. Fisheries 27:19-­‐25 Page 26 CRITFC (Columbia River Intertribal Fish Commission). 2008. Tribal Pacific lamprey restoration plan for the Columbia River Basin. Formal Draft by Nez Perce, Umatilla, Yakama, and Warm Springs Tribes, May 18 2008. 68 pp. Dole, D., and E. Niemi. 2004. Future water allocation and in-­‐stream values in the Willamette River Basin: A basin-­‐wide analysis. Ecological Applications 14:355–367 Hardisty, M.W., and I.C. Potter. 1971. The general biology of adult lampreys. in The biology of lampreys, vol. 1 (edited by M.W. Hardisty and I.C. Potter)pp. 127-­‐206. London-­‐New YorkAcademic Press. Keefer, M. L., M. L. Moser, C.T. Boggs, W.R. Daigle, and C.A. Peery. 2009a. Effects of body size and river environment on the upstream migration of adult Pacific Lamprey, North American Journal of Fisheries Management, 29:5, 1214-­‐1224 Keefer, M. L., M. L. Moser, C.T. Boggs, W.R. Daigle, and C.A. Peery. 2009b. Variability in migration timing of adult Pacific lamprey (Lampetra tridentata) in the Columbia River, U.S.A.. Environ Biol. Fish. 85:253-­‐264 Kostow, K. 2002. Oregon lampreys: natural history, status, and analysis of management issues. Oregon Department of Fish and Wildlife, Portland, OR. McIlraith, B.J., and C.C. Caudill. 2010. Evaluation of factors affecting migration success and spawning distribution of adult Pacific lamprey in the Snake River, Washington and Idaho. Progress report. Depart. Of Fish and Wildlife Resources. University of Idaho. Idaho. Mesa, M. G., J. M. Bayer, J. G. Seelye. 2003. Swimming performance and physiological responses to exhaustive exercise in radio-­‐tagged and untagged Pacific Lampreys, Transactions of the American Fisheries Society, 132:3, 483-­‐492 Mesa, M.G., Magie, R.J., and Copeland, E.S., 2009, Passage and behavior of radio-­‐tagged adult Pacific lamprey (Entosphenus tridentata) at the Wilamette Falls Project, Oregon, 2005–07: U.S. Geological Survey Open-­‐File Report 2009-­‐1223, 28 p. Moser, M.L., Matter, A.L., Struehrenberg, L.C., and Bjornn, T.C., 2002a, Use of an extensive radio receiver network to document Pacific lamprey (Lampetra tridentata) entrance efficiency at fishways in the Lower Columbia River, USA: Hydrobiologia, v. 483, p. 45-­‐53. Moser, M. L., P. A. Ocker, L. C. Stuehrenberg, and T. C. Bjornn. 2002b. Passage efficiency of adult pacific lampreys at hydropower dams on the lower Columbia River, USA. Transactions of the American Fisheries Society 131:956-­‐965. ODFW. 2009. Fish Passage data. Available online. http://www.dfw.state.or.us/fish/fish_counts/willamette/2009/09_counts_willamette%20falls.
asp Page 27 ODFW. 2010. Fish Passage data. Available online. http://www.dfw.state.or.us/fish/fish_counts/willamette/2010/2010_counts_willamette%20fal
ls.asp Raff, L. 2008. A taste of tradition. The Bulletin. Accessed Online http://www.bendbulletin.com/article/20080817/NEWS0107/808170307/. Robinson, T.C., and J.M. Bayer. 2005. Upstream migration of Pacific lampreys in the John Day River, Oregon: Behavior, timing, and habitat use. U.S. Geological Survey, Western Fisheries Research Center, Columbia River Research Laboratory, 5501A Cook-­‐Underwood Road, Cook, Washington 98605 Scott, W. B., and E. J. Crossman. 1973. Freshwater fishes of Canada. Fisheries Research Board of Canada Bulletin 184. Sedell, J.R., and J.L. Froggat. 1984. Importance of streamside forests to large rivers: The isolation of the Willamette River, Oregon, U.S.A, from its floodplain by snagging and streamside forest removal. USDA Forest Service, Forestry Sciences Laboratory, 3200 S. W. Jefferson Way, Corvallis, Oregon 97331, U. S. A. USFWS (U.S. Fish and Wildlife Service). 2004. Endangered and threatened wildlife and plants; 90-­‐
day finding on a petition to list three species of lampreys as threatened or endangered. Federal Register. 69:77158–77167. USFWS (U.S. Fish and Wildlife Service). 2011. Pacific Lamprey (Entosphenus tridentatus) Assessement and Template for Conservation Measures. USGS. 2010. USGS 14211720 WILLAMETTE RIVER AT PORTLAND, OR. Available online http://waterdata.usgs.gov/or/nwis/uv/?site_no=14211720&PARAmeter_cd=00010 Waldman, J., C. Grunwald., and I. Wirgin. 2008. Sea lamprey Petromyzon marinus: an exception to the rule of homing in anadromous fishes. Evolutionary Biology. 4: 659-­‐662 Willamette Falls Heritage Foundation. 2011. History of Willamette Falls/ History of Station A. Available online: http://willamettefalls.org/Hist/Elec Wydoski, R. S., and R. R. Whitney. 2003. Inland fishes of Washington, 2nd edition. University of Washington Press, Seattle. Page 28