Evaluation of Dual Frequency Identification Sonar (DIDSON) for Monitoring Pacific Lamprey Passage Behavior at Fishways of Bonneville Dam, 2011
CORPS OF ENGINEERS PORTLAND OR NORTH PACIFIC DIV
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The relationship between lamprey swimming behavior and passage success in fishways remains unclear, though previous telemetry studies have indicated poor passage at several locations including fishway entrances and transition pools. In the summer of 2011, we completed a Dual-Frequency Identification Sonar DIDSON pilot study at Bonneville Dam to evaluate potential applications of this technology for passively observing Pacific lamprey Entosphenus tridentatus behavior and passage at fine scales 1-5 m. A secondary objective was to determine whether DIDSON monitoring could provide quantitative estimates for common passage metrics e.g., entrance efficiency. Two DIDSON cameras were deployed from 6 June to 2 September among six existing locations at Bonneville Dam Washington-shore junction pool, Powerhouse 2 north upstream and downstream entrances, Powerhouse 2 south upstream and downstream entrances, and Cascades Island fishway entrance excluded from analysis because we found the available deployment location was unsuitable. Data were collected in high frequency mode at each location for periods of 24 to 72 hours. DIDSON images were collected in landscape mode with the long axis of the sample volume parallel to the ground to obtain information on upstream and downstream movements and to assess horizontal distribution. Images were also collected in portrait mode to identify lamprey depth distributions. We also summarized the presence or absence of white sturgeon Acipenser transmontanus, a lamprey predator. We collected 1,413 h of DIDSON imagery and a total of 228 h of imagery was viewed 16 of total collected using a randomized sub-sampling approach. Overall, 123 h were landscape files 54 of the viewed sample and 105 h were portrait files 46. Two-thirds of the subsample was from night-time hours, which were preferentially sub-sampled given the higher nocturnal activity of the species.
- Acoustic Detection and Detectors