Zack Larson and Associates

Dual-frequency Identification Sonar (DIDSON) is promising new technology for enumerating anadromous fish in rivers. DIDSON is a multi-beam, high-definition imaging sonar that produces video-like images of fish and can detect fish as far as 80 meters away. DIDSON is generally positioned in the water near the bank to view a cross section of the channel. Fish are imaged and counted as they pass through the sonar beams. Unbiased fish counts and reasonably accurate length measurements can be derived.

The Alaska Department of Fish and Game (ADF&G) has tested DIDSON for counting salmon in rivers and the technology has consistently exceeded their expectations for counting salmon. They also find the technology increases their confidence in overall fish passage numbers, improves their credibility with user groups and ultimately makes fisheries management decisions easier.

Investigate the usefulness of DIDSON for monitoring salmon and steelhead abundance in coastal California Rivers.

Develop standardized approaches to operating sonar fish counting stations on North Coast rivers.

Complement ongoing fisheries research Help California achieve anadromous fisheries

management objectives.

CDFG Fisheries Restoration Grants Program Steelhead Report Card County of Del Norte Smith River Advisory Council Smith River Alliance California Trout Humboldt State University Alexandre EcoDairy Farms Sound Metrics Corporation Ocean Marine Industries Northern California FFF Zack Larson & Associates (Project Leader)

2008 Smith River DIDSON Workshop

The Smith River Sonar Station is located 6 river miles from the Pacific Ocean at the Public Boat Launch Facility off Fred Haight Drive near the town of Smith River.

Two Long Range DIDSON units are deployed from both sides of the Smith River 24 hours per day, 7 days per week from October 1 to April 15th.

Data is recorded in 20 and 30 minute files and immediately processed in an onsite utility building connected to grid power.

Justin Garwood, DFG

Three fish observed from22 meters to 25 meters from shore

Length measurements of targets can be recorded with the Sound Metrics DIDSON software. The individual fish shown to the right is approximately 3.7 feet or 44 inches in length.

EMPIRICAL DATA

Total Upstream Detections 43,479 Total Downstream Detections 11,235 Net Upstream Detections 32,234

Chinook salmon and steelhead estimates25 Oct – 15 Dec (Chinook salmon):

Net Upstream Detections 21,958 16 Dec – 15 Apr (Steelhead)

Total Upstream Detections 12,475

Smith River DIDSON Pilot Study: Upstream Fish Counts and River Discharge, October 2011

-25

2

-12 -19

70

11398

677361

-114

8975

142

267

333369

244

364

512

272281

349

284

394

242

540

423

461

179

547

-150

-50

50

150

250

350

450

550

650

Oct. 1Oct. 2Oct. 3Oct. 4Oct. 5Oct. 6Oct. 7Oct. 8Oct. 9Oct. 10Oct. 11Oct. 12Oct. 13Oct. 14Oct. 15Oct. 16Oct. 17Oct. 18Oct. 19Oct. 20Oct. 21Oct. 22Oct. 23Oct. 24Oct. 25Oct. 26Oct. 27Oct. 28Oct. 29Oct. 30Oct. 31

Date

Numbers of Fish

-150

-50

50

150

250

350

450

550

650

Flow (cfs x 10)

# FISH

FLOW x10(cfs )

WEEK # UPSTREAM # DOWNSTREAM TOTAL UPSTREAM FISH FISHING EFFICIENCY

Oct. 1-8 6647 3378 3269 86.34%

Oct. 9-16 6080 3158 2922 98.69%

Oct. 17-24 6453 5956 497 98.95%

Oct. 25-Nov.1 6191 5646 545 98.71%

Running Total 25371 18138 7233 95.97%

WEEK #UPSTREAM#DOWNSTREA

M TOTAL UPSTREAM FISH % FISHING EFFICIENCY Oct. 25 - 30 2304 801 1503 42.44%Nov. 1 - 7 3831 #VALUE! #VALUE! 49.56%Nov. 8 - 15 7502 2052 5450 78.22%Nov. 16 - 23 8166 2758 5408 85.88%Nov. 24 - Dec. 1 5203 1490 3713 88.57%Dec. 2 - Dec. 9 3071 741 2330 92.60%Dec. 10 - Dec. 17 1209 189 1020 88.45%Dec. 18 - Dec. 25 986 104 882 82.56%Dec. 26 - Jan. 2 1121 93 1028 79.20%Jan. 3 - Jan. 10 1507 141 1366 97.15%Jan. 11 - Jan. 18 1805 94 1711 97.76%Jan. 19 - Jan. 26 1556 78 1478 97.80%Jan. 27 - Feb. 3 769 132 637 96.89%Feb. 4 - Feb. 11 655 193 462 98.22%Feb. 12 - Feb. 19 1159 167 992 97.50%Feb. 20 - Feb. 27 1033 233 800 96.95%Feb. 28 - Mar. 7 592 156 436 80.04%Mar. 8 - Mar. 15 182 66 116 38.44%Mar. 16 - Mar. 23 269 132 137 87.27%Mar. 24 - Mar. 31 159 100 59 80.30%Apr. 1 - Apr. 8 183 126 57 99.17%Apr. 9 - Apr. 15 217 314 -97 99.61%

2010/2011

2011/2012

SONAR STATION EFFICIENCY