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Monitoring fish migration in Rivers

Monitoring fish migration in Rivers. Helge Balk Department of Physics. University of Oslo. River Tana. River Tana. Tornio (Se/Fi). River Reisa (north Norw.). River Fischa in Austria. 4-Ch TVG. Echosounder in the river. Amplitude Detector. 1 size correction. Phase detector.

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Monitoring fish migration in Rivers

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  1. Monitoring fish migration in Rivers Helge Balk Department of Physics. University of Oslo.

  2. River Tana

  3. River Tana

  4. Tornio (Se/Fi)

  5. River Reisa (north Norw.)

  6. River Fischa in Austria

  7. 4-Ch TVG Echosounder in the river Amplitude Detector 1 size correction Phase detector

  8. What we can do to increase the detection probability Estimate the DPF Reduce the variation in the DPF Site selection Bottom modification Surface modification Guide fish Opening angle Sound frequency

  9. If we detect a fish, What does it mean? Echo sounder Fish detection software ?

  10. Interpretation: DPF, noise and time expansion Echo sounder Fish detector Interpreter Meaningful statistics Measure noise level as a function of time and range over years Apply noise level as an overall fish size threshold Use noise level to correct the number of fish within each size group Apply time expansion to find the total fish abundance estimate

  11. What did we cover? Interpretation: Area expansion ! Echo sounder Fish detector Interpreter Meaningful statistics! Where did the fish pass? Index or total run?

  12. Can we estimate TS in a river? • Spherical or cylindrical spreading? • Corrupted vertical angular measurements? • Additive noise? • Can we compensate for swimming motion? • Can we compensate for fish aspect?

  13. Can we estimate TS in a river? Alternative methods to establish the size? Beam intensity mapping? Apply reference targets? Multiple narrow beams? Multiple frequencies? Aspect detection and correction?

  14. x

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