To: David Clugston, USACE Portland District From: Matt Keefer, Eric Johnson, Tami Clabough, Mike Jepson, Chris Caudill, Mary Moser RE: Preliminary evaluation of radiotelemetry and half-duplex PIT tag data for Pacific lamprey at Bonneville Dam in 2009 Date: 25 September 2009 Introduction Modifications to the Cascades Island (CI) fishway opening designed to improve entry rates for adult Pacific lamprey were installed prior to the 2009 migration. Because the changes may affect behavior and passage success, radiotelemetry and half-duplex PIT-tag (HD-PIT) studies are underway. This report summarizes preliminary data on: 1) Passage times and behaviors of radio-tagged lampreys at Bonneville Dam through 30 August 2009. 2) Dam passage time metrics and CI entrance use and passage efficiency metrics from radio-tagged lampreys in 2009 with comparison to similar metrics from lamprey radiotelemetry data collected in 2007-2008 through 30 August in all years. 3) Detections of HD-PIT tagged and double-tagged (radio and HD-PIT) lampreys at the new CI HD antennas through 30 August 2009. These data represent the best analyses currently available but all analyses and conclusions should be considered provisional until release of the final reports for the projects because telemetry monitoring of the Pacific lamprey continues at this writing. We also note that experimental fishway entrance velocity tests in all years at PH2 complicate interpretation of data at those sites (see Johnson et al. 2009). Methods Radiotelemetry. From 1 June-25 August 2009, we collected and surgically implanted radio-tags into 596 adult Pacific lampreys at the Adult Fish Facility at Bonneville Dam and released tagged fish downstream from the dam near Tanner Creek and Hamilton Island 1
(Figure 1). A description of the collection and tagging methods is presented in Keefer et al. (2009). A total of 8,434 adult lampreys were counted passing the dam during the day through the end of August. Radio-tagged lampreys represented ~ 7.1% of the lampreys counted at the dam (day only) during the tagging period. Presumably the tagged percentage would be lower if nighttime passage was known. We compared lamprey passage times, fallback rates, and efficiency metrics in 2009 to similar data collected in 2007-2008. In all analyses, we excluded all telemetry records that were recorded after 30 August for each year analyzed. This approach was intended to limit confounding seasonal effects like faster passage time later in the summer and make data most comparable across years. HD-PIT. From 1 June to 2 September 2009, we collected and implanted HD-PIT tags into 368 adult lamprey at the Adult Fish Facility at Bonneville Dam and released them downstream from the dam at Hamilton Island. HD-PIT tags were also inserted into approximately half of the radio-tagged fish. Lamprey detection data at the four floor-mounted HD antennas inside the CI entrance were downloaded on 30 August 2009, concurrent with a download of the adjacent CI radiotelemetry antennas was on 30 August. Consequently, 30 August was used as the final date for these preliminary evaluations. We calculated HD detection efficiency using the double-tagged fish using both HD and/or radiotelemetry antennas inside the CI entrance. CI Passage metrics We considered five passage time and passage efficiency metrics to help assess potential effects of the CI entrance modifications on radio-tagged adult lamprey behavior: 1) CI entrance efficiency. The ratio of unique fish recorded entering the CI fishway to the number that approached the CI fishway (entrances/approaches). 2) CI exit ratio. The ratio of unique fish recorded exiting the CI fishway into the tailrace to the number that entered the CI fishway (exits/entrances). 3) CI entrance time. The passage time from first CI fishway approach to first CI fishway entrance. 4) CI entrance to base of ladder time. The passage time from first CI fishway entrance to the first record at the antenna located in the transition pool at the base of the ladder. 5) Extended passage time percentages. Because passage times were strongly rightskewed in all years, we calculated the percentage of fish that required > 1 h to pass through the two passage segments. 2
Results Compared to 2007 and 2008, the river environment through August 2009 had intermediate levels of total discharge and spill (Figure 2). Water Quality Monitoring (WQM) station water temperatures in June, July, and August 2009 were generally similar to temperatures in 2007 and were warmer than in 2008. Of the 596 lampreys radio-tagged and released through 25 August 2009, 547 (92%) were recorded on receiver sites in the tailrace (near the release sites) and 467 (78%) were recorded at the dam (Table 1). Four fish (2%) had no valid telemetry records. Of the 596 fish released, 167 (28%) had passed the dam and another 22 (4%) were recaptured in the lamprey traps and released upstream from the dam (Table 1). Sixty-nine passage events (41%) were recorded via the Bradford Island fishway and 97 (58%) were recorded via the Washington-shore fishway. There was one unknown passage likely via the navigation lock which was not monitored in 2009. The 28% passage rate in 2009 was slightly lower than in either 2007 (31%) and 2008 (32%). We recorded 33 fallback events by 33 unique lampreys in 2009; none had re-ascended the dam by 30 August. (Note: it is possible that some of these were false positives that may be reclassified when telemetry data at upstream sites is coded.) Distributions of first approaches and entries In 2009, about 25% of all the first fishway approaches by radio-tagged lampreys were recorded at Powerhouse 1 and 55% were recorded at Powerhouse 2 (Figure 3). About 7% of first fishway approaches were at the Cascade Island opening and 12% were at the Bradford Island fishway opening. These percentages were not substantially different than in 2007-2008. First fishway entrances were most common at the Powerhouse 2 entrance(s) in 2009 (~30% at PH2 south entrances and ~27% at PH2 north entrances) and were least common at the Cascades Island (~9%) and Powerhouse 1 north entrances (~8%) (Figure 4). First fishway approach efficiency In 2009, the percentage of first fishway approaches that resulted in first fishway entries at the same site ranged from 13% (n = 126 first approaches) at the PH2 north entrance (adjacent to the powerhouse) to 68% (n = 19) at the PH1 north entrance (Figure 5). Percentages at other sites in 2009 were 42% (n = 92) at the south entrance at PH1, 59% (n = 34) at the Cascades Island entrance, 59% (n = 56) at the B-Branch entrance, 25-48% (n = 16-71) at the PH2 south entrances, and 18% (n = 38) at the downstream PH2 north entrance. The 2009 estimates were mixed in comparison to 2007-2008, with some higher and some lower; the Cascades Island estimate was higher than both 2007 and 2008. Passage Times The median time from lamprey release to the first fishway approach in 2009 (1.52 d, n = 440) was the fastest time observed in the three study years (Table 2). The median release to 3
first fishway entrance time in 2009 (2.91 d, n = 254) was also the fastest of the three years. The median time for radio-tagged lampreys to pass Bonneville Dam (release to ladder top) in 2009 was 7.29 d (n = 141), intermediate to the 2007 and 2008 times. The median time from first fishway approach to first fishway entry in (0.60 h, n = 254) was the fastest of the three years. The median time tagged lampreys used to swim from first fishway entry to the ladder top was 2.43 d in 2009 (n = 92), slower than times for this segment in previous years. The proportion of unique lamprey that exited after entry at Cascade Island and Bradford Island were higher in 2009 than in 2007 and 2008. In summary, entrance efficiencies were higher in 2009, however, exit ratios were greater as were median passage times from approach to entry and entry to the base of the ladder compared to 2007 and 2008. Preliminary 2009 Cascades Island Results: radiotelemetry The Cascades Island entrance has been infrequently used by radio-tagged lampreys in all study years. This results in small sample sizes. Metric 1. The CI first entrance efficiency estimate in 2009 was 0.568 (n = 81 radiotagged fish approached) (Table 3). This was considerably higher than in 2007 (0.459) and 2008 (0.333). Preliminary 2009 result suggests entrance efficiency may have improved relative to the last two years. The 2009 estimate was significantly higher (P = 0.012, 2 2 χ 2 test) than in 2008 but not in 2007 (P = 0.370). However, due to the smaller sample size in 2007 (N = 37), the statistical power was lower for the 2009 vs. 2007 comparison. Metric 2. The CI exit ratio in 2009 was 0.617 (n = 29 of 47 fish that entered eventually exited) through 30 August (Table 3) compared to 0.588 (n = 19 fish) in 2007 and 0.167 (n = 18 fish) in 2008. Metric 3. The 2009 median passage time from first CI approach to first CI entry was 42 minutes (n = 20), slightly longer than 2007 and 2008 (Table 3). Metric 4. After fish entered the CI fishway, the median time to reach the ladder base was 16 minutes in 2009 (n = 23), versus 7-9 minutes in the previous two years (Table 3). The 2009 estimate was significantly longer (P = 0.033, K-W test). Metric 5. In 2009, 30% of the lamprey took >1 h to pass through the CI approach-ci entry segment (n = 6) intermediate to 2007 and 2008 values and 27% took > 1 h to pass from CI entry to the base of the ladder (n = 6, Table 3) a higher percentage than 2007 and 2008. Preliminary 2009 Cascades Island Results: HD-PIT A total of 67 lampreys with HD-PIT tags were recorded at one or more of the four HD antennas inside the CI fishway through 30 August 2009. Of these, 39 (59%) were from HD- PIT-only fish and 27 (40%) were from double-tagged fish. The final tag was from a lamprey tagged in 2008. The 39 HD-PIT-only fish were 11% of the 368 released. 4
The largest number of HD-PIT tagged fish (n = 57, 85% of 67) were recorded on antenna 3 (Figure 6). Detections at the other antennas ranged from 17 fish (25%) at antenna 4 to 31 fish (46%) at antenna 2. Twenty-three fish (34%) were recorded at only one HD antenna, 27 (40%) were recorded at two, 13 (20%) were recorded at three, and 4 (6%) were recorded at all four antennas. The majority (n = 52, 78%) were first recorded at antenna 3, followed by 14 (21%) first recorded at antenna 1 and one (1%) first recorded at antenna 2. Detection patterns suggested most fish moved from downstream to adjacent upstream antennas (i.e., from antenna 3 to antenna 4 or from antenna 1 to antenna 2, though there were a variety of movements. We note that, late in the season, we discovered a broken power/data cable to one of the antennas.) Twenty-nine double-tagged lampreys were recorded entering the CI fishway using the radiotelemetry system through 30 August. Twenty-six of these fish were also detected on one or more HD antennas for an overall HD detection efficiency of 90% with all antennas pooled. An additional nine double-tagged lampreys moved downstream through the UMT channel and exited into the tailrace presumably through the CI fishway opening. None of these nine fish were recorded on the HD antennas (detection efficiency = 0%), perhaps indicating they were relatively high in the water column while moving downstream. Only one double-tagged fish was recorded on the HD antennas without being recorded on the radiotelemetry antennas; this fish entered during a radiotelemetry receiver outage. Discussion and Preliminary Conclusions In general, radio-tagged lamprey passage rate through 30 August 2009 has been similar to or slightly better than in 2007-2008. Proportionately more lampreys have passed the dam (~32%) in 2009 than had by 30 August in either of the two previous years (21-26%). Median passage times to first approach a fishway, first enter a fishway, and from first approach to first fishway entry were faster in 2009 than in 2007-2008, while the time from entry to pass the dam was longer than in previous years. At Cascade Island, we compared metrics between years and also to estimates from Bradford Island (Table 4). Entrance efficiency at Cascade Island through 30 August (~57%) was higher than in previous years, at ~36% (2008) and ~46% (2007). However, the exit ratio was slightly higher in 2009 (62%) compared to previous years (14-59%), and passage time metrics indicated the slowest passage of the three years. Entrance efficiencies and exit ratios were also slightly inflated at the Bradford Island fishway entrance compared to prior years, and passage times were the longest, suggesting that variables other than structural modifications may have contributed to the increases in all metrics at Cascade Island in 2009 (compare Tables 3 & 4). Though preliminary, the results suggests improvements in some Cascade Island passage metrics post-modification because entrance efficiencies improved. While passage times increased in 2009 at the Cascade Island entrance, an increase in passage times of similar magnitude was also observed at the Bradford Island entrance. The preliminary HD-PIT data at Cascades Island indicated that the new detection system was working well. The HD detection efficiency was 100% for the 26 double-tagged fish available through 30 August. Detection ranges for the floor-mounted antennas is believed to be < 2 feet. Therefore, the results indicate that lampreys were moving through the entrance 5
area close to the floor, presumably through the near-bed area of lowered velocity created by the artificial rocks (a.k.a. bollards). In other lamprey-specific installations (i.e., the LPS s), lamprey use of the structures was relatively lower in the first years compared to subsequent years. There has been speculation that the newly-installed metal is unattractive to some fish for olfactory or other reasons. If this is the case in the Cascade Island modification as well, then it is possible that passage will further improve at this site in future years as the metal substrates season as they are covered by biofilms. 6
300 30 Daytime lamprey count at Bonneville 250 200 150 100 50 no. tagged dam count 25 20 15 10 5 Number of radio-tagged lamprey released 0 30-May 14-Jun 29-Jun 14-Jul 29-Jul 13-Aug 28-Aug 0 Figure 1. The number of Pacific lampreys radio-tagged and released downstream from Bonneville Dam and the number of adult lampreys counted passing the dam (through 30 August, 2009). 450 240 Flow (kcfs) 400 350 300 250 200 150 2007 100 2008 2009 50 10 May 30 May 19 Jun 9 Jul 29 Jul 19 Aug Spill (kcfs) 220 200 180 160 140 120 100 80 60 40 10 May 30 May 19 Jun 9 Jul 29 Jul 19 Aug 26 Temperature (deg C) 24 22 20 18 16 14 12 10 10 May 30 May 19 Jun 9 Jul 29 Jul 19 Aug Date Figure 2. Mean daily flow, spillway discharge, and WQM water temperature at Bonneville Dam from 10 May to 30 August, 2007-2009. 7
0.4 Proportion of first fishway approaches 0.3 0.2 0.1 2007 2008 2009 0.0 PH1 S PH1 N B-Branch Casc Is PH2 S PH2 N Unk Approach site Figure 3. Distribution of first fishway approach sites used by radio-tagged adult Pacific lamprey at Bonneville Dam through 30 August, 2007-2009. Unk = unknown approach site. 0.5 Proportion of first fishway entrances 0.4 0.3 0.2 0.1 2007 2008 2009 0.0 PH1 S PH1 N B-Branch Casc Is PH2 S PH2 N Unk Entry site Figure 4. Distribution of first fishway entry sites used by radio-tagged adult Pacific lamprey at Bonneville Dam through 30 August, 2007-2009. Unk category includes fish recorded in the transition pools at PH1 or PH2 without clear entry records. 8
First fishway entry:approach efficiency 1.0 0.8 0.6 0.4 0.2 2007 2008 2009 0.0 PH1 S PH1 N B-Branch Casc Is PH2 S-1 PH2 S-2 PH2 N-1 PH2 N-2 Entrance site Figure 5. Percentage of first fishway approaches resulting in first fishway entries at the same site for all fishway openings at Bonneville Dam through 30 August, 2007-2009. Figure 6. Overhead view of the four floor-mounted HD-PIT antennas (A1-A4) located inside the Cascades Island fishway entrance in 2009. The variable width weir replaced the bulkhead leading to the tailrace in the photo. 9
Table 1. Number of adult Pacific lampreys released downstream from Bonneville Dam and number and percentage of those released that were recorded at the dam, that passed the dam, that were recorded on their first approach at a fishway opening, first fishway entry, and exit from the top of a ladder. 2007 2008 2009 n % n % n % Released 398 595 596 Recorded at tailrace 368 92.5 569 95.6 547 91.8 Recorded at dam 265 66.6 432 72.6 467 78.4 Known to pass dam 82 20.6 154 25.9 189 31.7 Recaptured, released upstream 1 10 1.7 22 3.7 Recorded first fishway approach 2 260 65.3 385 64.7 445 74.6 Recorded first fishway entrance 2 169 42.5 190 31.9 254 42.6 Recorded ladder exit 71 17.8 130 21.8 167 28.0 1 included in the known to pass dam category 2 only includes known time and location of approach and entry Table 2. Lamprey passage times at Bonneville Dam through 30 August, 2007-2009. All fishways and antenna sites combined. 2007 2008 2009 n median n median n median Release to first fishway approach 260 2.84 d 385 1.57 d 440 1.52 d Release to first fishway entry 169 3.54 d 190 3.54 d 254 2.91 d Release to pass dam 71 7.56 d 130 5.56 d 141 7.29 d First fishway approach to first entry 169 0.81 h 190 1.37 h 254 0.60 h First fishway entry to pass dam 62 1.23 d 84 1.94 d 92 2.43 d Table 3. Cascades Island fishway entrance efficiency metrics through 30 August, 2007-2009. Metrics were calculated using the total number of unique fish at the entrance, and were not limited to first detections. Cascades Island entrance metrics 2007 2008 2009 # Metric n Estimate n Estimate n Estimate 1 Entrance efficiency 37 0.459 54 0.333 81 0.568 2 Exit ratio 17 0.588 18 0.167 29 0.617 3 Med. time: approach to entry 16 9 min 17 35 min 20 42 min 4 Med. time: entry to ladder 15 7 min 15 9 min 22 16 min 5 Approach-entry time > 1 h 16 13% 17 41% 6 30% 5 Entry-ladder time > 1 h 15 7% 15 7% 6 27% 10
Table 4. Bradford Island fishway entrance efficiency metrics through 30 August, 2007-2009. Metrics were calculated using the total number of unique fish at the entrance, and were not limited to first detections. Bradford Island entrance metrics 2007 2008 2009 # Metric n Estimate n Estimate n Estimate 1 Entrance efficiency 80 0.489 106 0.462 66 0.541 2 Exit ratio 39 0.615 49 0.693 47 0.712 3 Med. time: approach to entry 39 12 min 48 32 min 57 66 min 4 Med. time: entry to ladder 27 15 min 30 16 min 32 32 min 5 Approach-entry time > 1 h 39 18% 48 35% 28 49% 5 Entry-ladder time > 1 h 27 22% 30 7% 32 31% 11
References cited Johnson, E. L., T. S. Clabough, M. L. Keefer, C. C. Caudill, C. A. Peery, and M. L. Moser. 2009. Effects of lowered nighttime velocities on fishway entrance success by Pacific lamprey at Bonneville Dam and fishway use summaries for lamprey at Bonneville and The Dalles dams, 2008. Technical Report 2009-10 of Idaho Cooperative Fish and Wildlife Research Unit, to U.S. Army Corps of Engineers, Portland District, Portland, OR. Keefer, M.L., C. A. Peery, C. C. Caudill, E. L. Johnson, C. T. Boggs, B. Ho, and M. L. Moser. 2009. Adult Pacific lamprey migration in the lower Columbia River: 2008 radiotelemetry and half-duplex PIT-tag studies. Technical Report 2009-8 of Idaho Cooperative Fish and Wildlife Research Unit report to the U.S. Army Corps of Engineers, Portland District, Portland, Oregon. 12