Estimates of chinook salmon abundance in the Kenai River using split-beam sonar, 2001

93 Pages·2003·1.01 MB·English

Fishery Data Series No. 03-03
Estimates of Chinook Salmon Abundance in the
Kenai River Using Split-beam Sonar, 2001
by
James D. Miller,
Debby L. Burwen,
and
Steve J. Fleischman
February 2003
Alaska Department of Fish and Game Division of Sport Fish
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FISHERY DATA SERIES NO. 03-03
ESTIMATES OF CHINOOK SALMON ABUNDANCE IN THE KENAI
RIVER USING SPLIT-BEAM SONAR, 2001
by

James D. Miller
and
Debby L. Burwen
Division of Sport Fish, Anchorage
and
Steve J. Fleischman
Division of Sport Fish, Research and Technical Services, Anchorage
Alaska Department of Fish and Game
Division of Sport Fish, Research and Technical Services
333 Raspberry Road, Anchorage, Alaska, 99518-1599

February 2003
This investigation was partially financed by the Federal Aid in Sport Fish Restoration Act
(16 U.S.C. 777-777K) under project F-10-17, Job No. S-2-5b.
The Fishery Data Series was established in 1987 for the publication of technically-oriented results for a single
project or group of closely related projects. Fishery Data Series reports are intended for fishery and other technical
professionals. Fishery Data Series reports are available through the Alaska State Library and on the Internet:
http://www.sf.adfg.state.ak.us/statewide/divreports/html/intersearch.cfm This publication has undergone editorial
and peer review.
James D. Miller, Debby L. Burwen,
Alaska Department of Fish and Game, Division of Sport Fish
and Steve J. Fleischman
Alaska Department of Fish and Game, Division of Sport Fish, Research and Technical Services
333 Raspberry Road, Anchorage, Alaska 99518-1599, USA

This document should be cited as:
Miller, J. D., D. L. Burwen, and S. J. Fleischman. 2003. Estimates of chinook salmon abundance in the Kenai
River using split-beam sonar, 2001. Alaska Department of Fish and Game, Fishery Data Series No. 03-03,
Anchorage.
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If you believe you have been discriminated against in any program, activity, or facility, or if you desire further
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For information on alternative formats for this and other department publications, please contact the department
ADA Coordinator at (voice) 907-465-4120, (TDD) 907-465-3646, or (FAX) 907-465-2440.
TABLE OF CONTENTS
Page
LIST OF TABLES..........................................................................................................................................................................iii
LIST OF FIGURES........................................................................................................................................................................iv
LIST OF APPENDICES...............................................................................................................................................................vi
ABSTRACT ......................................................................................................................................................................................1
INTRODUCTION............................................................................................................................................................................1
METHODS........................................................................................................................................................................................5
Study Area..........................................................................................................................................................................................5
Site Description.................................................................................................................................................................................5
Acoustic Sampling............................................................................................................................................................................5
Sonar System Configuration......................................................................................................................................................7
Bottom Mapping and Beam Coverage...................................................................................................................................10
System Calibration....................................................................................................................................................................11
Sampling Procedure..................................................................................................................................................................11
Echo Sounder Settings..............................................................................................................................................................11
Data Acquisition........................................................................................................................................................................11
Fish Tracking and Echo Counting...............................................................................................................................................14
Data Analyses..................................................................................................................................................................................14
Tidal and Temporal Distribution............................................................................................................................................14
Spatial Distribution...................................................................................................................................................................15
Target Strength Distribution....................................................................................................................................................16
Species Discrimination.............................................................................................................................................................16
Passage Estimates......................................................................................................................................................................16
Net-apportioned Estimates............................................................................................................................................................19
RESULTS........................................................................................................................................................................................20
System Calibration.........................................................................................................................................................................20
Beam Coverage...............................................................................................................................................................................20
Target Tracking...............................................................................................................................................................................20
Tidal and Temporal Distribution..................................................................................................................................................20
Spatial Distribution.........................................................................................................................................................................21
Vertical Distribution.................................................................................................................................................................21
Range Distribution....................................................................................................................................................................22
Target Strength...........................................................................................................................................................................26
Passage Estimates......................................................................................................................................................................30
DISCUSSION.................................................................................................................................................................................33
Spatial Distribution.........................................................................................................................................................................33
Bank Preference.........................................................................................................................................................................33
Vertical Distribution.................................................................................................................................................................39
Range Distribution....................................................................................................................................................................39
Target Strength................................................................................................................................................................................40
Direction of Travel.........................................................................................................................................................................41
Comparison of Passage Estimates with Other Indices.............................................................................................................41
Early Run....................................................................................................................................................................................42
Late Run......................................................................................................................................................................................45
Outlook.............................................................................................................................................................................................48
i
TABLE OF CONTENTS (Continued)
Page
Inriver Netting............................................................................................................................................................................51
Pulse Width................................................................................................................................................................................51
Imaging Sonar............................................................................................................................................................................52
ACKNOWLEDGMENTS.............................................................................................................................................................52
LITERATURE CITED..................................................................................................................................................................53
APPENDIX A. TARGET STRENGTH ESTIMATION........................................................................................................57
APPENDIX B. SYSTEM PARAMETERS..............................................................................................................................59
APPENDIX C. DATA FLOW....................................................................................................................................................67
APPENDIX D. DAILY PROPORTIONS OF UPSTREAM AND DOWNSTREAM FISH FOR THE 2001
EARLY AND LATE KENAI RIVER CHINOOK SALMON RUNS..................................................................................69
APPENDIX E. AVERAGE VERTICAL ANGLE BY TIDE STAGE, RUN, BANK, AND FISH
ORIENTATION (UPSTREAM OR DOWNSTREAM) FOR THE 2001 KENAI RIVER CHINOOK SALMON
RUNS................................................................................................................................................................................................73
APPENDIX F. HISTORIC ESTIMATES OF INRIVER RETURN BY YEAR AND DATE (1987–2001)...............77
APPENDIX G. FILTERED (CONVENTIONAL), UNFILTERED, AND NET-APPORTIONED CHINOOK
PASSAGE ESTIMATES, KENAI RIVER SONAR, EARLY AND LATE RUNS, 2001...............................................81

ii
LIST OF TABLES
Table Page
1. Principal components of the split-beam sonar system used in 2001........................................................................7
2. HTI model 244 digital echo sounder settings used in 2001....................................................................................11
3. Echo acceptance criteria for digital echo processing, 2001.....................................................................................13
4. Results of 2001 in situ calibration verifications using a 38.1 mm tungsten carbide standard sphere..............21
5. Estimates of chinook salmon passage by tide stage and direction of travel for the 2001 early run
(16 May to 30 June).......................................................................................................................................................22
6. Estimates of chinook salmon passage by tide stage and direction of travel for the 2001 late run (1 July
to 10 August)...................................................................................................................................................................22
7. Estimates of early-run fish passage by direction of travel, 2001............................................................................32
8. Estimates of late-run fish passage by direction of travel, 2001..............................................................................32
9. Mean target strength (dB) for upstream and downstream targets by bank (chinook only) during the
early (16 May-30 June) and late (1 July-10 August) runs, 2001............................................................................32
10. Estimated daily upstream passage of chinook salmon, Kenai River sonar, early run, 2001.............................35
11. Estimated daily upstream passage of chinook salmon, Kenai River sonar, late run, 2001................................36

iii
LIST OF FIGURES
Figure Page
1. Cook Inlet showing location of the Kenai River.........................................................................................................2
2. The Kenai River showing location of chinook salmon sonar site, 2001.................................................................6
3. Cross-sectional (top) and aerial (bottom) views of sonar site showing insonified portions of the Kenai
River, 2001.........................................................................................................................................................................8
4. Daily right- and left-bank transducer locations and counting ranges relative to bipod tower located on
the right bank, Kenai River, 2001..................................................................................................................................9
5. Left- and right-bank bottom profiles at the Kenai River chinook sonar site with approximate transducer
locations and sonar beam coverage for 16 May 2001..............................................................................................10
6. Schematic diagram of 2001 split-beam sonar system configuration and data flow............................................12
7. Distribution of upstream and downstream fish by tide stage during the early and late runs, Kenai River,
2001...................................................................................................................................................................................23
8. Vertical distributions of early-run upstream and downstream fish on the left and right banks, Kenai
River, 2001.......................................................................................................................................................................24
9. Vertical distributions of early-run upstream fish during falling, low, and rising tide stages on the left
and right banks, Kenai River, 2001.............................................................................................................................25
10. Vertical distributions of late-run upstream and downstream fish on the left and right banks, Kenai
River, 2001.......................................................................................................................................................................26
11. Vertical distributions of late-run upstream fish during falling, low, and rising tide stages on the left and
right banks, Kenai River, 2001.....................................................................................................................................27
12. Range distributions of early-run upstream and downstream fish on the left and right banks, Kenai
River, 2001.......................................................................................................................................................................28
13. Range distributions of early-run upstream fish during falling, low, and rising tide stages on the left and
right banks, Kenai River, 2001.....................................................................................................................................29
14. Range distributions of late-run upstream and downstream fish on the left and right banks, Kenai River,
2001...................................................................................................................................................................................30
15. Range distributions of late-run upstream fish during falling, low, and rising tide stages on the left and
right banks, Kenai River, 2001.....................................................................................................................................31
16. Early-run target strength distributions for all upstream and downstream targets on the left and right
banks, Kenai River, 2001..............................................................................................................................................33
17. Late-run target strength distributions for all upstream and downstream targets on the left and right
banks, Kenai River, 2001..............................................................................................................................................34
18. Daily sonar estimates of passage by bank (top panel), total passage (center panel), and historical
cumulative proportions for the early run of chinook salmon returning to the Kenai River, 2001....................37
19. Daily sonar estimates of passage by bank (top panel), total passage (center panel), and historical
cumulative proportions for the late run of chinook salmon returning to the Kenai River, 2001......................38
20. Daily CPUE of chinook and sockeye salmon from inriver gillnetting, 16 May-10 August, 2001...................42
21. Range distribution of all (unfiltered) upstream targets on the left and right banks during the early run,
16-30 May, 31 May-15 June, and 16-30 June, Kenai River, 2001........................................................................43
22. Daily discharge rates at the Soldotna Bridge and Secchi depth readings in front of the sonar site, Kenai
River, early run (16 May–30 June), 2001...................................................................................................................44
23. Daily sonar estimates and inriver gillnet CPUE of chinook salmon during the early run (16 May–30
June), Kenai River, 2001...............................................................................................................................................45
24. Filtered (conventional), unfiltered, and net-apportioned estimates of chinook salmon passage, for the
early and late runs, Kenai River sonar, 2001.............................................................................................................46
25. Daily chinook salmon sonar estimates with chinook salmon sport fish CPUE (open triangles represent
days on which only unguided anglers were allowed to fish), early run (16 May-30 June), 2001....................47
26. Daily chinook sonar estimates and river mile-19 sockeye sonar estimates lagged one day, late run (1
July–10 August), 2001...................................................................................................................................................48
27. Range distribution of all (unfiltered) upstream targets on the left and right banks during the late run, 1-
13 July, 14-31 July, and 1-10 August, Kenai River, 2001.......................................................................................49
28. Daily discharge rates at the Soldotna Bridge and Secchi depth readings in front of the sonar site, Kenai
River, late run (1 July–10 August), 2001...................................................................................................................50
iv
LIST OF FIGURES (Continued)
Figure Page
29. Daily sonar estimates and inriver gillnet CPUE for chinook salmon during the late run (1 July–10
August), 2001..................................................................................................................................................................50
30. Cumulative sonar estimates with cumulative inriver net CPUE, late-run chinook salmon (1 July–10
August), 2001..................................................................................................................................................................51
31. Daily chinook salmon sonar estimates with chinook salmon sport fish CPUE (open triangles represent
days on which only unguided anglers were allowed to fish), late run (1 July-31 July), 2001..........................52

v
LIST OF APPENDICES
Appendix Page
A1. Using the sonar equation to estimate target strength with dual- and split-beam applications...........................58
B1. Example of system parameters used for data collection on the right bank (transducer 733)............................60
B2. Example of system parameters used for data collection on the left bank (transducer 738)...............................63
C1. Inseason data flow diagram for the Kenai River chinook salmon sonar project, 2001......................................68
D1. Daily proportions of upstream and downstream fish for the 2001 Kenai River early chinook run..................70
D2. Daily proportions of upstream and downstream fish for the 2001 Kenai River late chinook run....................71
E1. Average vertical angle by tide stage and orientation for the 2001 Kenai River early chinook run, 2001.......74
E2. Average vertical angle by tide stage and orientation for the 2001 Kenai River late chinook run....................75
F1. Kenai River early-run chinook salmon sonar estimates of inriver return, 1987-2001........................................78
F2. Kenai River late-run chinook salmon sonar estimates of inriver return, 1987-2001..........................................79
G1. Filtered (conventional), unfiltered, and net-apportioned chinook passage estimates, Kenai River sonar,
early run, 2001.................................................................................................................................................................82
G2. Filtered (conventional), unfiltered, and net-apportioned chinook passage estimates, Kenai River sonar,
late run, 2001...................................................................................................................................................................83

vi