Count data: Pass 1 = 102 Pass 2 = 81 Pass 3 = 97. Range of counts = 0 to 30. Largest count range within sites = 12. Mean count range within sites = 3.8. Results ...
Missing:
Side-Scan Sonar and White Sturgeon Acipenser transmontanus in the Snake River Jacob B. Hughes Idaho Power Company
Acknowledgements Joe Hightower Jared Flowers
Tim Stuart, Dave Meyer, Chad Reininger & Brandon Bentz
Introduction
Side-Scan Images
Pilot Study
Questions
What is Sonar? Transmission and detection of sound waves underwater.
Versus Mark-Recapture Side-Scan Sonar Pros: • Saves time = Saves $$$ • Repeatable transects • Gear not dependent on certain fish behavior (e.g., hungry) • True “Snapshot” – Abundance – Distribution
• Reduces handling
Side-Scan Sonar Cons: • Upfront costs • No Capture history • Less biological data • Limitations
Methods & Survey Design Deployment: Fixed mount @ 0.6 m depth Sonar Settings: 1200 kHz 20 m range (per side)
Survey: 10 sites 3 passes per site Collect & Post-process: SonarWiz 5 Shadow and Length to ID Estimate Abundance: N-Mixture Model (Bayesian)
Introduction
Side-Scan Images
Pilot Study
Questions
Results
Effort: 3 man-days to survey (1.5 days) 1.5 days to process
Survey Length: 66 transects; 1-4 transects per pass Mean transect length = 357 m (R: 146-913 m) Count data: Pass 1 = 102
Pass 2 = 81
Pass 3 = 97
Range of counts = 0 to 30 Largest count range within sites = 12 Mean count range within sites = 3.8
Side-Scan Images
Pilot Study
Questions
Side-Scan Sonar Results 35 Pass 1
Pass 2
Pass 3
30 Number Counted
Introduction
25
20 15 10 5 0 1
2
3
4
5
6
7
8
Site
Model Results (95 % BCI ) Abundance (N) = 131 (120-150) Detection probability (p) = 0.71 (0.61-0.79)
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Introduction
Side-Scan Images
Pilot Study
Questions
Side-Scan Sonar
What we learned Substrate size and type matters Not all fish can be measured or seen Colder water = less fish movement Overlap is good – if not necessary Abundance estimate Looking Ahead 2016 - CJS-Swan Falls Dam - Compare to M/R
Introduction
Side-Scan Images
Pilot Study
Questions
Questions? “Counting fish is like counting trees, except they are invisible and they keep moving.” – John Shepherd