Estimates of chinook salmon abundance in the Kenai River using

74 Pages·2002·1.61 MB·English

Fishery Data Series No. 98-2
Estimates of Chinook Salmon Abundance in the
Kenai River Using Split-Beam Sonar, 1996
by
Debby Burwen
and
Daniel Bosch
February 1998
Alaska Department of Fish and Game Division of Sport Fish

FISHERY DATA SERIES NO. 98-2
ESTIMATES OF CHINOOK SALMON ABUNDANCE IN THE KENAI
RIVER USING SPLIT-BEAM SONAR, 1996
by

Debby Burwen
and
Daniel Bosch
Division of Sport Fish, Anchorage

Alaska Department of Fish and Game
Division of Sport Fish, Research and Technical Services
333 Raspberry Road, Anchorage, Alaska, 99518-1599

February 1998
This investigation was partially financed by the Federal Aid in Sport Fish Restoration Act
(16 U.S.C. 777-777K) under project F-10-12, 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. Distribution is to state and local publication distribution centers, libraries and individuals and, on
request, to other libraries, agencies, and individuals. This publication has undergone editorial and peer review.
Debby Burwen and Daniel Bosch
Alaska Department of Fish and Game, Division of Sport Fish
333 Raspberry Road, Anchorage, Alaska 99518-1599, USA

This document should be cited as:
Burwen, D. and D. Bosch. 1998. Estimates of chinook salmon abundance in the Kenai River using split-beam
sonar, 1996. Alaska Department of Fish and Game, Fishery Data Series No. 98-2, Anchorage.
The Alaska Department of Fish and Game administers all programs and activities free from discrimination on the
basis of sex, color, race, religion, national origin, age, marital status, pregnancy, parenthood, or disability. For
information on alternative formats available for this and other department publications, contact the department ADA
Coordinator at (voice) 907-465-4120, or (TDD) 907-465-3646. Any person who believes s/he has been
discriminated against should write to: ADF&G, PO Box 25526, Juneau, AK 99802-5526; or O.E.O., U.S.
Department of the Interior, Washington, DC 20240.
TABLE OF CONTENTS
Page
LIST OF TABLES........................................................................................................................................................iii
LIST OF FIGURES......................................................................................................................................................iv
LIST OF APPENDICES................................................................................................................................................v
ABSTRACT..................................................................................................................................................................1
INTRODUCTION.........................................................................................................................................................1
METHODS....................................................................................................................................................................3
Study Area.....................................................................................................................................................................3
Site Description.............................................................................................................................................................3
Acoustic Sampling.........................................................................................................................................................5
Sonar System Configuration.....................................................................................................................................5
System Calibration....................................................................................................................................................7
Sampling Procedure..................................................................................................................................................7
Echo Sounder Settings..............................................................................................................................................7
Data Acquisition.......................................................................................................................................................8
Fish Tracking and Echo Counting.................................................................................................................................8
Data Analyses..............................................................................................................................................................10
Tidal and Temporal Distribution.............................................................................................................................10
Spatial Distribution.................................................................................................................................................10
Target Strength Distribution...................................................................................................................................10
Species Discrimination...........................................................................................................................................10
Passage Estimates and Run Timing.........................................................................................................................11
RESULTS....................................................................................................................................................................12
System Calibration.......................................................................................................................................................12
Target Tracking...........................................................................................................................................................12
Tidal and Temporal Distribution.................................................................................................................................13
Spatial Distribution......................................................................................................................................................13
Target Strength............................................................................................................................................................20
Passage Estimates........................................................................................................................................................20
Total Passage..........................................................................................................................................................24
Net Upstream Passage.............................................................................................................................................24
DISCUSSION..............................................................................................................................................................28
Bank Preference......................................................................................................................................................28
Vertical Distribution...............................................................................................................................................38
Range Distribution..................................................................................................................................................38
Target Strength.......................................................................................................................................................39
Direction of Travel and Debris...............................................................................................................................39
Species Classification.............................................................................................................................................40
ACKNOWLEDGMENTS...........................................................................................................................................41
LITERATURE CITED................................................................................................................................................44
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TABLE OF CONTENTS (Continued)
Page
APPENDIX A. TARGET STRENGTH ESTIMATION............................................................................................47
APPENDIX B. EQUIPMENT AND SOFTWARE SETTINGS................................................................................49
APPENDIX C. DAILY PROPORTIONS OF UPSTREAM AND DOWNSTREAM FISH FOR THE 1996
EARLY AND LATE KENAI RIVER CHINOOK RUNS..........................................................................................57
APPENDIX D. AVERAGE VERTICAL ANGLE BY TIDE STAGE, RUN, BANK, AND FISH
ORIENTATION (UPSTREAM OR DOWNSTREAM) FOR THE 1996 KENAI RIVER CHINOOK RUNS........61

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LIST OF TABLES
Table Page
1. Principal components of the split-beam sonar system used in 1996................................................................5
2. 1996 settings for HTI model 240 digital echo sounder...................................................................................8
3. Echo acceptance criteria for digital echo processing, 1996.............................................................................9
4. Results of 1996 in situ calibration verifications using a 38.1 mm tungsten carbide standard sphere............13
5. Estimates of chinook salmon passage by tide stage and direction of travel for the 1996 early run (16
May to 30 June).............................................................................................................................................13
6. Estimates of chinook salmon passage by tide stage and direction of travel for the 1996 late run (1 July
to 31 July)......................................................................................................................................................14
7. Range distribution (5 m increments) for upstream- and downstream-traveling fish during the 1996 early
run (16 May to 30 June)................................................................................................................................24
8. Range distribution (5 m increments) for upstream- and downstream-traveling fish during the 1996 late
run (1 July to 31 July)....................................................................................................................................28
9. Estimates of 1996 early-run fish passage by direction of travel. Variance estimates are in parenthesis.......32
10. Estimates of 1996 late-run fish passage by direction of travel. Variance estimates are in parenthesis.........32
11. Mean target strength for upstream and downstream targets by bank during the early (16 May-30 June)
and late (1 July-31 July) runs, 1996..............................................................................................................32
12. Estimated daily chinook salmon passage, Kenai River Sonar, early run, 1996.............................................35
13. Estimated daily chinook salmon passage, Kenai River Sonar, late run, 1996...............................................36

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LIST OF FIGURES
Figure Page
1. Map of lower Kenai River showing location of the 1996 sonar site................................................................4
2. Aerial and cross-sectional views of sonar site showing insonified portions of the Kenai River, 1996............6
3. Schematic diagram of 1996 split-beam sonar system configuration and data flow.........................................9
4. Upstream and downstream components of the early (top) and late (bottom) runs of chinook salmon to
the Kenai River, 1996....................................................................................................................................15
5. Distribution of upstream and downstream fish by tide stage during the early run (top) and late run
(bottom).........................................................................................................................................................16
6. Vertical distributions of early-run upstream and downstream fish, on the left bank, Kenai River, 1996......17
7. Vertical distributions of early-run upstream and downstream fish, on the right bank, Kenai River, 1996....17
8. Vertical distribution of early-run, upstream-traveling fish during falling (top), low (middle), and rising
(bottom) tide stages on the left bank, Kenai River, 1996..............................................................................18
9. Vertical distribution of early-run, upstream-traveling fish during falling (top), low (middle), and rising
(bottom) tide stages on the right bank, Kenai River, 1996............................................................................19
10. Vertical distributions of late-run upstream- and downstream-traveling fish, on the left bank, Kenai
River, 1996....................................................................................................................................................21
11, Vertical distributions of late-run upstream- and downstream-traveling fish, on the right bank, Kenai
River, 1996....................................................................................................................................................21
12. Vertical distribution of late-run upstream-traveling fish during falling (top), low (middle), and rising
(bottom) tide stages on the left bank, Kenai River, 1996..............................................................................22
13. Vertical distribution of late-run upstream-traveling fish during falling (top), low (middle), and rising
(bottom) tide stages on the right bank, Kenai River, 1996............................................................................23
14. Range distributions of early-run upstream (n = 4,523) and downstream (n = 219) fish, on the left bank,
Kenai River, 1996.........................................................................................................................................25
15. Range distributions of early-run upstream (n = 2,605) and downstream (n = 283) fish, on the right bank,
Kenai River, 1996.........................................................................................................................................25
16. Range distribution of early-run, upstream-traveling fish during falling (top), low (middle), and rising
(bottom) tide stages on the left bank, Kenai River, 1996..............................................................................26
17. Range distribution of early-run, upstream-traveling fish during falling (top), low (middle), and rising
(bottom) tide stages on the right bank, Kenai River, 1996............................................................................27
18. Range distribution of late-run upstream (n = 6,538) and downstream (n = 238) fish, on the left bank,
Kenai River, 1996.........................................................................................................................................29
19. Range distribution of late-run upstream (n = 10,238) and downstream (n = 458) fish, on the right bank,
Kenai River, 1996.........................................................................................................................................29
20. Range distribution of late-run upstream-traveling fish during falling (top), low (middle), and rising
(bottom) tide stages on the left bank, Kenai River, 1996..............................................................................30
21. Range distribution of late-run upstream-traveling fish during falling (top), low (middle), and rising
(bottom) tide stages on the right bank, Kenai River, 1996............................................................................31
22. Early-run target strength distributions for upstream and downstream fish on the left (top) and right
(bottom) banks...............................................................................................................................................33
23. Late-run target strength distributions for upstream and downstream fish on the left (top) and right
(bottom) banks...............................................................................................................................................34
24. Daily sonar estimates of passage for the early run of chinook salmon returning to the Kenai River,
1996. Estimates by bank (left) and total run (right)......................................................................................37
25. Migratory-timing curves for early (left) and late (right) runs of chinook salmon to the Kenai River,
1996 (solid lines). Mean migratory-timing curves for the years 1987-1995 (dotted lines), and 95%
confidence intervals (dashed lines) are presented for comparison.................................................................37
26. Daily sonar estimates of passage for the late run of chinook salmon returning to the Kenai River, 1996.
Estimates by bank (left) and total run (right).................................................................................................38
27. Range distribution of late-run upstream-traveling fish from 1-13 July during falling (top), low (middle),
and rising (bottom) tide stages on the right bank, Kenai River, 1996............................................................42
28. Range distribution of late-run upstream-traveling fish from 14-31 July during falling (top), low
(middle), and rising (bottom) tide stages on the right bank, Kenai River, 1996............................................43
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LIST OF APPENDICES
Appendix Page
A1. Using the sonar equation to estimate target strength with dual- and split-beam applications........................48
B1. Criteria used for the collection of echoes for the right bank transducer........................................................50
B2. Criteria used for the collection of echoes for the left bank transducer..........................................................53
C1. Daily proportions of upstream and downstream fish for the 1996 Kenai River early chinook run................58
C2. Daily proportions of upstream and downstream fish for the 1996 Kenai River late chinook run..................59
D1. Average vertical angle by tide stage and orientation for the 1996 early Kenai River chinook run................62
D2. Average vertical angle by tide stage and orientation for the 1996 late Kenai River chinook run..................63

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