Principles of Fisheries Acoustics
         Data Analysis

             Hydroacoustics 103
                     By
        ...
Using BioSonics Visual Analyzer™
 Acoustic Data Analysis Software
     For Fish Stock Assessment




  2003-2009 Copyright...
Data Analysis Module
Point-Source Targets:
     Echo Recognition and Counting
     Trace Formation
Volumetric Analysis:
  ...
Multiple Targets in Fish Schools




        2003-2009 Copyright BioSonics, Inc. All Rights Reserved
Counting When Single Targets Are Resolved




           2003-2009 Copyright BioSonics, Inc. All Rights Reserved
Range and Angular Resolution




      2003-2009 Copyright BioSonics, Inc. All Rights Reserved
Resolving Fish Echoes
                                                            t2 – t1 >         pulse duration

      ...
Dead Zone Near Bottom

                                                  Fish can not be detected
                        ...
Visual Resolution




2003-2009 Copyright BioSonics, Inc. All Rights Reserved
Digital Resolution




 2003-2009 Copyright BioSonics, Inc. All Rights Reserved
Single and Overlapping Echoes




      2003-2009 Copyright BioSonics, Inc. All Rights Reserved
Pulse Duration Criteria


     V
                                                      -6 dB level or 0.5 amplitude


    ...
Single Target Criteria: Echo Correlation
   Comparing of shape of echo envelope with transmitted pulse




               ...
Counting Methods
• Require Single Echo Recognition

• Echoes Over Threshold are Counted

• Echoes May be Assembled into Fi...
Abundance Estimation
•   Count Echoes
•   Estimate Sampled Volume
•   Calculate Density
•   Extrapolate over Sample Area t...
Density Estimation from Trace Counts




         2003-2009 Copyright BioSonics, Inc. All Rights Reserved
Density Estimation from Echo Counts




         2003-2009 Copyright BioSonics, Inc. All Rights Reserved
Sample Volume Estimate




    2003-2009 Copyright BioSonics, Inc. All Rights Reserved
Overlap Biases




2003-2009 Copyright BioSonics, Inc. All Rights Reserved
Echo Integration




2003-2009 Copyright BioSonics, Inc. All Rights Reserved
Echo Integration
• Technique used for echo signal processing of multiple
  objects.
• Summing echo intensity (energy) from...
Echo Integration Principle

•I = N *    bs


•I   V2

•Density = V2 * A

•A is the Echo Integrator Scaling Factor

•In dig...
Digital Signal Integration




•Only samples greater than threshold are processed.
•Samples less than threshold level are ...
Scaling Factor of Echo Integrator



         Fish Parameter                               Instrument parameters



Where ...
Echo Integration                                                                         High Densities
• Fish densities i...
Models of Echo Integration

  L o w d en sities                                     H ig h d en sities                    ...
Example of Echo Integration using Visual Analyzer




    Step 1: ProgramCopyright BioSonics, Inc. All Rights Reserved
   ...
Step 2: Program Echo Recognition




   2003-2009 Copyright BioSonics, Inc. All Rights Reserved
Step 3: Define Analysis Cells and Resolution




        2003-2009 Copyright BioSonics, Inc. All Rights Reserved
VERTICAL INTEGRATION RESULTS

      STRATA     TOP           BOTTOM Sv (dB)            Applied Sigma                    FP...
V O L U M E B A C K S C A T T E R IN G S T R E N G T H (d B )


                  REPORT            1   REPORT           2...
P E R C E N T IN T E G R A T E D M A T R IX


                 REPORT       1       REPORT         2 REPORT             3 ...
Horizontal map of survey
Survey Output Reports were imported to GIS and data were interpolated
           Fish Density per...
Vertical cross-section of the transect
    Fish Density per Unit Volume (1/m3) or (kg/m3)




      2003-2009 Copyright Bi...
Visual Bottom Typer




  2003-2009 Copyright BioSonics, Inc. All Rights Reserved
EcoSAV




   Software for Measuring
Submerged Rooted Vegetation



   2003-2009 Copyright BioSonics, Inc. All Rights Rese...
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Fisheries Acoustics 103 - Analysis

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Acoustic Data Analysis for Fisheries Assessment Using BioSonics Visual Analyzer Processing Software

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Fisheries Acoustics 103 - Analysis

  1. 1. Principles of Fisheries Acoustics Data Analysis Hydroacoustics 103 By BioSonics, Inc. 2003-2009 Copyright BioSonics, Inc. All Rights Reserved
  2. 2. Using BioSonics Visual Analyzer™ Acoustic Data Analysis Software For Fish Stock Assessment 2003-2009 Copyright BioSonics, Inc. All Rights Reserved
  3. 3. Data Analysis Module Point-Source Targets: Echo Recognition and Counting Trace Formation Volumetric Analysis: Bathymetry (depth) Echo Integration (fish) VBT (Sea Floor Classification) EcoSAV (Submerged Vegetation) 2003-2009 Copyright BioSonics, Inc. All Rights Reserved
  4. 4. Multiple Targets in Fish Schools 2003-2009 Copyright BioSonics, Inc. All Rights Reserved
  5. 5. Counting When Single Targets Are Resolved 2003-2009 Copyright BioSonics, Inc. All Rights Reserved
  6. 6. Range and Angular Resolution 2003-2009 Copyright BioSonics, Inc. All Rights Reserved
  7. 7. Resolving Fish Echoes t2 – t1 > pulse duration (2 R2 / c) - (2 R1 / c) > R2 –R1 > (c / 2) for no overlap ____________________ c = 1500 m/second = 1.5 m/msec c/2 = 3/4 m/msec t0 t1 = (2 R 1 / c) t2 = (2 R 2 / c) 2003-2009 Copyright BioSonics, Inc. All Rights Reserved
  8. 8. Dead Zone Near Bottom Fish can not be detected in “dead zone” near boundaries (here bottom). “Dead zone” near the bottom is defined by beam angle, range, and pulse duration. 2003-2009 Copyright BioSonics, Inc. All Rights Reserved
  9. 9. Visual Resolution 2003-2009 Copyright BioSonics, Inc. All Rights Reserved
  10. 10. Digital Resolution 2003-2009 Copyright BioSonics, Inc. All Rights Reserved
  11. 11. Single and Overlapping Echoes 2003-2009 Copyright BioSonics, Inc. All Rights Reserved
  12. 12. Pulse Duration Criteria V -6 dB level or 0.5 amplitude -12 dB level or 0.25 amplitude Threshold -18 dB level or 0.125 amplitude Time Duration of echo should be approximately equal to duration of transmitted pulse. 2003-2009 Copyright BioSonics, Inc. All Rights Reserved
  13. 13. Single Target Criteria: Echo Correlation Comparing of shape of echo envelope with transmitted pulse n fish echo transmit replica i 1 Correlatio n n n 2 2 fish echo transmit replica i 1 i 1 Where: n = the number of samples in an ideal pulse, i = sample index 2003-2009 Copyright BioSonics, Inc. All Rights Reserved
  14. 14. Counting Methods • Require Single Echo Recognition • Echoes Over Threshold are Counted • Echoes May be Assembled into Fish Traces 2003-2009 Copyright BioSonics, Inc. All Rights Reserved
  15. 15. Abundance Estimation • Count Echoes • Estimate Sampled Volume • Calculate Density • Extrapolate over Sample Area to Estimate Abundance 2003-2009 Copyright BioSonics, Inc. All Rights Reserved
  16. 16. Density Estimation from Trace Counts 2003-2009 Copyright BioSonics, Inc. All Rights Reserved
  17. 17. Density Estimation from Echo Counts 2003-2009 Copyright BioSonics, Inc. All Rights Reserved
  18. 18. Sample Volume Estimate 2003-2009 Copyright BioSonics, Inc. All Rights Reserved
  19. 19. Overlap Biases 2003-2009 Copyright BioSonics, Inc. All Rights Reserved
  20. 20. Echo Integration 2003-2009 Copyright BioSonics, Inc. All Rights Reserved
  21. 21. Echo Integration • Technique used for echo signal processing of multiple objects. • Summing echo intensity (energy) from multiple objects in a sampling volume or sampling area. • Various processing algorithms (averaging, filtering, etc.) • Echo integration can be used for: • Assessment of density (biomass) of fish, plankton, particles, etc. • Bottom classification • Aquatic vegetation assessment • EI survey data can be used for mapping if acquired with GPS information. 2003-2009 Copyright BioSonics, Inc. All Rights Reserved
  22. 22. Echo Integration Principle •I = N * bs •I V2 •Density = V2 * A •A is the Echo Integrator Scaling Factor •In digital form V2 is the sum of squared digital sample count values 2003-2009 Copyright BioSonics, Inc. All Rights Reserved
  23. 23. Digital Signal Integration •Only samples greater than threshold are processed. •Samples less than threshold level are rejected. 2003-2009 Copyright BioSonics, Inc. All Rights Reserved
  24. 24. Scaling Factor of Echo Integrator Fish Parameter Instrument parameters Where sonar system parameters are defined as: Source Level => Transmitted Power ( Pa at 1 m) SL = 10 log p02 Receiver Sensitivity => System Gain (V/ Pa) G=10 log g2 Beam pattern factor: b2( ) Sound velocity: c (m / s) Pulse duration: (ms) 2003-2009 Copyright BioSonics, Inc. All Rights Reserved
  25. 25. Echo Integration High Densities • Fish densities in lakes and oceans are on the order of 10-4 to 10-2 fish/m3 (scattered fish, median densities). • Fish densities in schools and in aquaculture pens (nets) are much higher: from 1 to 100 fish/m3, or up to 20 kg/m3. • Echo Integration is linear for low and medium densities, then begins to saturate. • The classic echo integration theory, based on the single scattering model, can not be applied for estimation of fish in high density aggregations due to attenuation of echo signal by densely distributed scatterers. Echo Integrator Saturation 3 Echo Integrator Output 2.5 2 1.5 1 0.5 0 1 18 35 52 69 86 103 120 137 154 171 188 205 222 239 256 273 290 307 324 341 Fish Density 2003-2009 Copyright BioSonics, Inc. All Rights Reserved
  26. 26. Models of Echo Integration L o w d en sities H ig h d en sities V ery H ig h d en sities S in g le S catterin g S in g le S catterin g w ith M u ltip le S catterin g A tten u atio n E n ergy tran sp o rt ran g e F o r v ery h ig h d en sity th e en v iron m en t co m es to b e n o n ho m o g en o u s: m ix tu re of w ater an d fish b od ies 2003-2009 Copyright BioSonics, Inc. All Rights Reserved
  27. 27. Example of Echo Integration using Visual Analyzer Step 1: ProgramCopyright BioSonics, Inc. All Rights Reserved 2003-2009 the bottom exclusion algorithm
  28. 28. Step 2: Program Echo Recognition 2003-2009 Copyright BioSonics, Inc. All Rights Reserved
  29. 29. Step 3: Define Analysis Cells and Resolution 2003-2009 Copyright BioSonics, Inc. All Rights Reserved
  30. 30. VERTICAL INTEGRATION RESULTS STRATA TOP BOTTOM Sv (dB) Applied Sigma FPCM ------ ------ ------ ------------- ------------- ------------- 1 1 4 -8.30E+01 1.00E-03 5.03E-06 2 4 6.9 -6.07E+01 1.00E-03 8.59E-04 3 6.9 9.9 -6.64E+01 1.00E-03 2.31E-04 4 9.9 12.9 -5.45E+01 1.00E-03 3.58E-03 5 12.9 15.9 -4.86E+01 1.00E-03 1.39E-02 HORIZONTAL INTEGRATION RESULTS RPT T IM E A N D D A T E D epth Latitud e Long itu de S v (dB ) S ig m a FPUA 1 10/0 1/96 21:27:00 7.4 41ø 30 .34 00' N 119ø 3 .64 00' W -5.50 E + 01 1.00 E -03 1.15 E -02 2 10/0 1/96 21:27:49 12.8 41ø 30 .32 00' N 119ø 3 .68 00' W -5.66 E + 01 1.00 E -03 6.91 E -03 3 10/0 1/96 21:28:35 13.5 41ø 30 .30 00' N 119ø 3 .72 00' W -5.66 E + 01 1.00 E -03 8.65 E -03 4 10/0 1/96 21:29:23 13.2 41ø 30 .32 00' N 119ø 3 .75 00' W -5.28 E + 01 1.00 E -03 9.38 E -03 5 10/0 1/96 21:30:13 10.5 41ø 30 .28 00' N 119ø 3 .82 00' W -5.24 E + 01 1.00 E -03 4.94 E -03 2003-2009 Copyright BioSonics, Inc. All Rights Reserved
  31. 31. V O L U M E B A C K S C A T T E R IN G S T R E N G T H (d B ) REPORT 1 REPORT 2 REPORT 3 REPORT 4 REPORT 5 STRATA 1 -8 .8 4 E + 0 1 -9 .0 1 E + 0 1 -7 .8 8 E + 0 1 -8 .4 9 E + 0 1 -8 .2 0 E + 0 1 STRATA 2 -5 .3 7 E + 0 1 -8 .7 1 E + 0 1 -9 .9 1 E + 0 1 -1 .0 7 E + 0 2 -7 .9 7 E + 0 1 STRATA 3 -5 .9 8 E + 0 1 -7 .2 4 E + 0 1 -7 .4 2 E + 0 1 -9 .1 5 E + 0 1 -8 .4 0 E + 0 1 STRATA 4 -4 .9 8 E + 0 1 -5 .7 4 E + 0 1 -5 .8 8 E + 0 1 -5 .8 5 E + 0 1 -5 .5 4 E + 0 1 STRATA 5 0 .0 0 E + 0 0 -5 .0 5 E + 0 1 -5 .0 2 E + 0 1 -4 .6 0 E + 0 1 -4 .5 8 E + 0 1 A B S O L U T E D E N S IT Y D IS T R IB U T IO N M A T R IX (IN N U M B E R P E R C U B IC M E T E R ) REPORT 1 REPORT 2 REPORT 3 REPORT 4 REPORT 5 STRATA 1 1 .4 6 E -0 6 9 .7 6 E -0 7 1 .3 1 E -0 5 3 .2 3 E -0 6 6 .3 7 E -0 6 STRATA 2 4 .2 8 E -0 3 1 .9 6 E -0 6 1 .2 4 E -0 7 2 .0 9 E -0 8 1 .0 8 E -0 5 STRATA 3 1 .0 6 E -0 3 5 .8 2 E -0 5 3 .7 9 E -0 5 7 .0 8 E -0 7 4 .0 3 E -0 6 STRATA 4 1 .0 5 E -0 2 1 .8 4 E -0 3 1 .3 3 E -0 3 1 .4 0 E -0 3 2 .8 8 E -0 3 STRATA 5 0 .0 0 E + 0 0 9 .0 1 E -0 3 9 .5 4 E -0 3 2 .4 9 E -0 2 2 .6 1 E -0 2 2003-2009 Copyright BioSonics, Inc. All Rights Reserved
  32. 32. P E R C E N T IN T E G R A T E D M A T R IX REPORT 1 REPORT 2 REPORT 3 REPORT 4 REPORT 5 STRATA 1 95.6 47 94.5 74 89.4 06 93.2 82 95.0 9 STRATA 2 71.5 98 95.1 5 89.9 51 93.8 5 91.1 89 STRATA 3 32.4 26 94.5 74 89.4 06 93.2 82 67.3 54 STRATA 4 4.32 81.3 76 89.9 51 93.8 5 45.3 28 STRATA 5 0 8.51 5 17.4 8 7.36 9 1.28 9 Percentage of integrated matrix is needed for estimation of sampling volume and biomass. Near the bottom sampling volume is smaller due to appearance of a bottom signal and this volume is not taken into consideration when estimating biomass: BIOMASS = FISH DENSITY * VOLUME 2003-2009 Copyright BioSonics, Inc. All Rights Reserved
  33. 33. Horizontal map of survey Survey Output Reports were imported to GIS and data were interpolated Fish Density per Unit Surface (1/m2) or (kg/m2) Absolute Density = A (Relative Density) A: Scaling factor 2003-2009 Copyright BioSonics, Inc. All Rights Reserved Area) Biomass = (Average Absolute Density) (Survey
  34. 34. Vertical cross-section of the transect Fish Density per Unit Volume (1/m3) or (kg/m3) 2003-2009 Copyright BioSonics, Inc. All Rights Reserved
  35. 35. Visual Bottom Typer 2003-2009 Copyright BioSonics, Inc. All Rights Reserved
  36. 36. EcoSAV Software for Measuring Submerged Rooted Vegetation 2003-2009 Copyright BioSonics, Inc. All Rights Reserved

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