The role of sonar in Copper River salmon escapement monitoring and commercial fisheries management. Bert Lewis, Alaska Dept.

Transcription

1 The role of sonar in Copper River salmon escapement monitoring and commercial fisheries management Bert Lewis, Alaska Dept. of Fish and Game

2 Ri chardson Highway CO PPER RIVER DRAINAGE Gu lkan a H atc heri es Denali Highway I II Summit Lak e P ax son N Paxso n La ke Slana River Chistochina River Midd le Fork S lana Gulkana River W est F ork Nabe sna Roa d Glenn H ighway Fish La ke Tanada Creek Cr ossw ind L ake Ew an Lak e Tazlina R ive r Ton sina River Va ldez G lenn Highway G lennallen N elchina River Klutina River Edg erto n Highway C hitina Richardson Highway McCa rt hy Nizin a Ri ver Chitina River Woo d C an yo n Brem er River Tas nuna River Co rdova Sonar Site Miles Lake M artin River Bering River Gulf o f Alas ka

3 Cordova Gov t. Rock Miles Lake Sonar Point Martin Hook Point COPPER RIVER DISTRICT Cape St.Elias

4 Copper River Ten Year Average Commercial Salmon Harvest ( ) Sockeye salmon 1.5 Million Chinook salmon 49,000 Coho salmon 300,000 Pink salmon 10,000 Chum salmon 18,000 Total 1.9 Million

5 Subsistence Salmon Harvest Lower Copper River 3-5,000 Glennallen Subdistrict Subsistence 60-75,000 Chitina Subdistrict Subsistence ,000

6 Copper River Salmon Management Difficulties 1) Glacially turbid water that prevents visual counts and 2) Lag time between fish passage through commercial fishery and their arrival at the spawning grounds

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8 Copper River Salmon Management Difficulties 1) Glacially turbid water that prevents visual counts and 2) Lag time between fish passage through commercial fishery and their arrival at the spawning grounds

9 Ri chardson Highway CO PPER RIVER DRAINAGE Gu lkan a H atc heri es Denali Highway I II Summit Lak e P ax son N Paxso n La ke Slana River Chistochina River Midd le Fork S lana Gulkana River W est F ork Nabe sna Roa d Glenn H ighway Fish La ke Tanada Creek Cr ossw ind L ake Ew an Lak e Tazlina R ive r Ton sina River Va ldez G lenn Highway G lennallen N elchina River Klutina River Edg erto n Highway C hitina Richardson Highway McCa rt hy Nizin a Ri ver Chitina River Woo d C an yo n Brem er River Tas nuna River Co rdova Sonar Site Miles Lake M artin River Bering River Gulf o f Alas ka

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11 Bendix Sonar Transducers operate at 515 khz with alternating beam widths of 2 and 4 degrees The system is powered by one 12-volt battery continuously recharged by a solar panel. Side-looking Bendix Sonar deployed in 1978 second unit deployed across river in 1979 Continuous use since then as one of primary management tools

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13 Bendix Oscilloscope

14 Bendix Sonar The Bendix systems have become outdated Difficult to repair and maintain System cannot store raw acoustic data

15 Bendix Replacement ADF&G began evaluating possible replacements

16 DIDSON 2 Frequency Multi-Beam Acoustic Lens Sonar 1.8 MHz freq: x12 beams 1 MHz freq: x12 beams Field of view: 29 Frame rate: 5-20 frames/s Weight in air: 15.4 lbs Beams formed by lens Ray Diagram Top View and curved element

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18 DIDSON View Of Salmon

19 DIDSON Advantages High resolution Moving targets easier to detect Simpler to aim Simpler to operate Accurate upstream/downstream target resolution Better coverage of water column Provides length and width of fish at short ranges Less multi-pathing Bendix Split Beam DIDSON

20 DIDSON Start-up Issues Expensive Power supply Memory storage

21 Miles Lake Sonar Site

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23 Power Supply

24 Power Supply

25 Power Supply

26 Data Management

27 South Bank Side-by-side Sonars

28 North Bank Long Range Didson

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31 PROMISING PRELIMINARY COMPARISON

32 Daily Passage Estimates DIDSON Bendix Jun 9 Jun 16 Jun 23 Jun 30 Jul 7 Jul 14 Jul 21 Jul Difference Between Estimates Jun 9 Jun 16 Jun 23 Jun 30 Jul 7 Jul 14 Jul 21 Jul Timeseries plots of DIDSON and Bendix passage estimates (top) and the difference between the estimates, DIDSON minus Bendix, (bottom), Copper River 2003.

33 Daily Passage Estimates DIDSON Bendix May 17 May 24 May 31 Jun 7 Jun 14 Jun 21 Jun 28 Jul 5 Jul 12 Jul 19 Jul Difference Between Estimates May 17 May 24 May 31 Jun 7 Jun 14 Jun 21 Jun 28 Jul 5 Jul 12 Jul 19 Jul Timeseries plots of DIDSON and Bendix passage estimates (top) and the difference between the estimates, DIDSON minus Bendix, (bottom), Copper River 2004.

34 Residuals2003.original Residuals Quantiles of Standard Normal Predicted(Bendix) Residuals2004.original Quantiles of Standard Normal Residuals Predicted(Bendix) Residuals compared against quantiles of the standard normal (left) and fitted versus residual plots from the regressions of DIDSON and Bendix passage estimates with DIDSON used as the predictor variable (right)

35 CONCLUSION Promising DIDSON/Bendix comparison Transition of equipment Validation of past escapement counts

36 ACKNOWLEDGEMENTS Alaska Dept. of Fish and Game Susan Maxwell and Dan Ashe Miles Lake Field Crew April, Karl, Don and Darce