Re: Experimental Evaluation of Fishway Modifications on the Passage Behavior of Adult Pacific Lamprey at Bonneville Dam

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1 Page 1 Summary Report To: David Clugston, USACE From: Eric Johnson, Matt Keefer, and Chris Peery (Fish Ecology Research Laboratory, University of Idaho), and Mary Moser (Northwest Fisheries Science Center, NOAA-Fisheries) Re: Experimental Evaluation of Fishway Modifications on the Passage Behavior of Adult Pacific Lamprey at Bonneville Dam Introduction Radiotelemetry studies suggest that lamprey have difficulty negotiating fishways at hydropower dams that were designed to pass adult salmonids (Moser et al. 2002). At Bonneville Dam, less than half of the radio tagged lamprey that approach the dam successfully pass (Moser et. 2002, 2005, Johnson el al. in review). Relatively low passage success for Pacific lamprey has been presumed to be a result of unfavorable conditions in and near fishways that create complex environments for migration, including high turbulent flows, physical barriers (serpentine weirs, diffuser gratings, sharp corners) and artificial lighting (count windows). Tests were conducted in an experimental fishway at the Bonneville Dam adult fish facility between 16 July and 4 August 2008 to evaluate the response of adult Pacific lamprey to proposed modifications at the Cascade Island fishway entrance. Modifications include redesigning the entrance, adding artificial rock structures to the bottom of the fishway to create velocity refuges for lamprey passage during high flows, and building a lamprey passage structure (LPS). Tests were conducted to evaluate passage times and behavior of Pacific lamprey under high flow conditions with and without velocity refuges. Additional tests were also performed to determine if lamprey using these refuges could be directed to a LPS. These tests were initiated after results from previous experimental flume studies indicated that velocity disruptors (artificial rocks) placed along the bottom of the fishway significantly decreased the passage time through orifices and through fishways under moderate flow (< 16 head and < 8.8 ft s -1 ) and did not affect fishway passage success rate (Daigle et. al 2005). Our goal was to test passage times and success using similar prototype rock structures at higher flows (24 head and > 11 ft s -1 ) that occur at fishway entrances. Tests where run to assess fish behavior and passage times under conditions with and without artificial rock refuges situated along the bottom of the experimental flume downstream of the orifice as well as upstream of the orifice along one side. The placement of refuges upstream of the orifice was to test the applicability to direct fish to a LPS once fish enter the fishway. Methods Flume design: The fishway was comprised of three main sections (listed from the upstream end; Figure 1). 1) A 2.0 long 8.0 deep collection area with fykes that allowed lamprey to enter but inhibited exits. The collection area was divided to separate lamprey that used the side of the fishway with rock refuges from those that used the smooth-bottomed side. 2) A 27 4 experimental section (10% slope) that consisted of a non-overflow weir with a submerged square

2 Page 2 orifice (18 ) with rounded bulkhead edges. The orifice was centered in the middle of the weir (Figure 2). Upstream of the weir along the bottom of the fishway was a 4 4 removable aluminum plate with wooden rocks refuges (3.5 high and 4.0 diameter). These refuges were positioned along one side of the flume upstream of the weir that led to a wall that divided the flume lengthwise (Figure 2). Downstream of the weir was a second removable aluminum plate (4 2 ) with refuges. Refuges were spaced 7.75 apart from their centers (crosscurrent) and 11.5 (upstream-to-downstream) in the first series of trials and 15.5 and 11.5 in subsequent trials. Rocks were positioned in a staggered pattern to break up flow along the bottom of the fishway. 3). At the downstream end was 2.6 long 8.0 deep rest box bounded by a removable perforated plate and a permanent perforated plate on the downstream end where fish were placed at the beginning of the test and allowed to acclimate to conditions before the plate was lifted to allow access to the experimental section of the flume. At the downstream end of the flume was an adjustable outflow wall to control pool height in the fishway. Water was supplied to the experimental flume by two 14 pipes capable of generating flows of 220 gal s -1. Lamprey collection: Fish were collected at night by portable traps as they ascended the Washington shore fishway at Bonneville Dam. Weights, lengths, and girths were taken for each fish and a half-duplex passive integrated transponder tag (HD PIT) was sutured to the base of the dorsal fin. Fish were held at least 10 hrs in covered aluminum tanks prior to each test. Movement through the experimental fishway was monitored using a series of swim-through HD PIT antennas just upstream of the release area, at the weir, and upstream of the weir on either side of the divided wall (Figure 3). Movements past the weir were observed at viewpoints built into the sides of the experimental channel and were also recorded using an infrared video camera. Two to four replicates of 10 fish each were performed during nighttime hours using a total of 130 HD PIT tagged fish. Tests were run for 2 h. Experiments were run with and without the rock structures and at head differentials of 2.0 (water velocities ft s -1 ) and 1.5 ft (water velocities ( ft s -1 ).

3 Page 3 Figure1. Experimental fishway configuration used for lamprey evaluations inside the Bonneville Dam adult fish facility. Figure 2. Photos of the experimental fishway looking downstream (left) and overhead (right) showing the placement of the divider wall, rock refuges, orifice (with swim-through antenna), and downstream swim-through antenna.

4 Page 4 Results Fish size.--there was no significant difference in fish weight by test (F = 0.3, P = 0.885, df = 4) or by trial (F = 0.9, P = 0.523, df = 11). Length and girth tests had similar results (Table 1). Table 1. Summary of tests Test Mean size Trial Test Head Rocks Spacing Date n Length Weight Girth Yes July Yes July Yes July No 21 July No 22 July No 23 July Yes July Yes July No 27 July No 28 July Yes July Yes August Passage success. PIT tag records and final locations of fish at the end of the 2 h trails were used to determine percent passage success. Chi-sq results with trials pooled within test: all five tests (χ 2 = 53.2, P < 0.001). Significant pairs: Test 1 v 3; Test 1 v 5; Test 2 v 3; Test 2 v 5; Test 3 v 4; Test 4 v 5 (P < in all cases). The majority of lamprey were able to pass the length of the flume with the lower (1.5 ft) head and at the high head (2 ft) without rocks (Figure 1). Fewer fish were successful with rocks present at the high head level. From visual observations, it was apparent that the spacing of the rocks was too narrow and interfered with fish attempts to move forward at the higher flow levels. A second series of tests were initiated using wider spacing intervals. Results were improved from the original design (40% vs 20% success). We modified the pattern further based on observations, but in the second trial 9 or 10 fish failed to move from the base of the flume during the trial. Because of the late date and warm water temperature, we suspected that the lamprey were less motivated to migrate and so trials were terminated for the year at this point.

5 Page Successful (%) Head (ft): Rocks: 1.5 Yes 1.5 No 2.0 Yes 2.0 No 2.0 Yes Spacing (in): Figure 1. Lamprey conversion rates through the experimental fishway (%). Different bar markings = Tests 1-5, from left. Passage times. Using PIT tag records and visual observation, we determined time for fish to pass through the test area of the flume (Figure 2). With all tests included, passage times were significantly different by test (F = 3.1, P = 0.022, df = 4). The trial term was non-significant (F = 1.0, P = 0.440, df = 7). Overall model (time = trial(test) + test) had F = 2.6, P = 0.009, df = 11. Tukey s pairwise tests were significant (P < 0.05) for: Test 3 v 4; Test 3 v 1; Test 3 v 2. Basically, the original 2.0 ft of head with original rocks pattern was the slow version.

6 Page Passage time (min) Head (ft): Rocks: Yes No Yes No Yes Spacing (in): Figure 2. Box plots of Antenna 4-Antenna 3 passage times using the first records at each antenna. Numbers above bar = n. Tests 1-5, from left. Mean and median passage times (minutes): 13.5, 12.0 (Test 1), 22.3, 13.5 (Test 2), 50.3, 49.0 (Test 3), 25.8, 20.5 (Test 4), 26.2, 25.0 (Test 5). Passage guidance. We used the final locations of lamprey at the end of the 2 h trials to determine the effectiveness of using rocks to guide lamprey direction of movement. In general, the lamprey appeared to favor moving along the left (facing upstream) side of the flume, with or without rocks (Figure 3). Statistically, there was not a significant difference in side selected by lamprey, relative to rock placement. Chi-sq results with trials pooled within tests (χ 2 = 2.4, P = 0.49) indicated that there was no significant difference in the proportion of lamprey caught in the rock refuge side of the trap compared to the smooth side of the trap.

7 Page 7 Figure 3. Percentage of lamprey caught in each side of the trap at the end of the 2 hours. Number above bar = n. Gray bars represent the side of trap fish were caught using the smooth side of the experimental flume and the black bars indicate trap location for those fish using the rock refuge side of the experimental flume. Entry time. We used visual recording to time to make a successful entry through the test configuration. Times were variable across trials. In general, times to pass though the entry area were consistent with behaviors notes above. At high velocities tested here, lamprey took 4 to 8 min on average to pass through the entry area (Table 2). Fish moved slowly along the bottom, often stationary (resting) for several minutes at a time between upstream movements. At time these upstream movements were interfered with by presence of rocks, lengthening passage times.

8 Page 8 Table 2. Numbers of lamprey observed approaching the submerged orifice, numbers of fish falling back through the orifice, the numbers of fish that successfully passed the orifice without falling back and mean passage time through the orifice. Times were calculated from the first time a lamprey came into camera view until it completely passed through the orifice. Test Trial Head Rocks Spacing Date Video No. Approach Fallback No. Pass Mean Passage time (min) Range (min) Yes July No Yes July No Yes July No No 21 July No No 22 July No No 23 July No Yes July Yes :54 4: Yes July Yes No 27 July Yes :03 2:25-6: No 28 July Yes :14 3:47-12: Yes July Yes :45 10: Yes August Yes :50 4:50 Discussion Designing a fishway entrance to accommodate both lamprey and salmon passage can be difficult. High velocities at entrances that are used to attract returning salmonids can result in reduced passage efficiencies of adult Pacific lamprey (Moser et al. 2002, Johnson et al. in review). We compared passage behavior in the experimental fishway flume to simulated conditions lamprey may encounter at a newly designed fishway entrance. Based on our comparison of passage efficiencies and times between treatments, the benefits of closely spaced artificial velocity refuges were unfavorable at higher flows (24 head and > 11 ft s -1 ) and insignificant at intermediate flows (18 head and < 10.1 ft s -1 ). When velocity refuges were present passage times (from release to passage through the submerged orifice) were significantly longer. Conversion rates through the flume during the high velocity treatments decreased from 60-90% success without rock refuges to < 20% with refuges. Daigle et al. (2005) observed passage efficiencies greater than 90% for seven of eight treatment groups with and without velocity refuges at head differentials ranging from and water velocities < 8.8 ft s -1 and found that velocity refuges at these flows significantly decreased the passage time through the submerged orifice as well as through the fishway. The two trials (n = 20) that we ran with 18 head and water velocities between ft s -1 resulted in similar passage efficiencies (90%). However, the presence of refuges did not significantly improve passage efficiencies or passage times.

9 Page 9 Observations at key locations during the high velocity treatments using infrared lights and camera indicated as many fish falling back through the orifice as those that passed. Passage times through the submerged orifice ranged from 3:47-12:44 minutes for individual fish with the average time ranging from 4:03-8:14 min (during trials of 2.0 ft without rocks). Passage times for the few fish that successfully passed the submerged orifice during the high velocity treatment with refuges ranged from 4:45 to 10:45 min. This is roughly a 2-4 fold increase in the average orifice passage times compared to those observed by Daigle et al. (2005) without refuges and at lower water velocities. Three general behaviors summarize fish behavior as they approached the submerged orifice during the high velocity with refuges resulting in low passage success 1) fish would approach the orifice from the side using the low flow area directly downstream of the weir followed by lateral movement toward the orifice. Refuges in front of the weir would inhibit lateral movement and fish would resort to other means to pass such as: 2) climbing over the downstream side of the weir or attaching to the rounded bulkhead; or 3) fish would approach the orifice directly downstream but upon entry into the high-velocity area inside the orifice, turbulent current would whip their body against a refuge immediately downstream and they would subsequently be pried from the fishway floor. In later trials we attempted to test modified patterns and spacing of refuges. There appeared to be improvement over the original refuge design, but time was not sufficient to continue experimentation to determine optimal spacing. Effects of fishway modifications such as velocity refuges in the experimental flume are designed and intended to provide information on the concept of using such structures to improve fish passage. However, due to large differences in scale rigorous conclusions based on these results can be confounding and should be used with caution. Based on initial studies conducted in the experimental fishway (Daigle et al. 2005), we demonstrated that velocity refuges can be beneficial. However, high velocities that occur at fishway entrances (up to 14 ft s -1 or more) make developing design criteria more challenging. Results of this study suggest that velocity refuges placed in close proximity especially in and just downstream from high velocity areas could be problematic to Pacific lamprey passage, particularly in areas where fish are forced to move laterally such as downstream of an LPS or directly downstream of a submerged orifice. Literature Cited Daigle, W.R. C.A. Peery, S.R. Lee, and M.L. Moser Evaluation of adult Pacific lamprey passage and behavior in an experimental fishway at Bonneville Dam. Idaho Cooperative Fish and Wildlife Research Unit, University of Idaho, Moscow, Idaho. Technical Report Johnson, E.L., C.A. Peery, and M.L. Moser. In review. Effects of lowered nighttime velocities on fishway entrance success by Pacific Lamprey at Bonneville Dam, Idaho Cooperative Fish and Wildlife Research Unit, University of Idaho, Moscow, Idaho. Moser, M.L., P.A. Ocker, L.C. Stuehrenberg, and T.C. Bjornn Passage efficiency of

10 Page 10 adult Pacific lamprey at hydropower dams on the lower Columbia River, USA. Transactions of the American Fisheries Society 131: