Qualark Creek. Split-beam system. History. Using split-beam technology. Single beam system (fish finder) What is a Sonar (Hydroacoustic) system?

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1 Single beam system (fish finder) Qualark Creek Not particularly good for counting fish! How far away YES! How big.no! Which way it s going..no! Dept. Fisheries & Oceans Canada Applied Technologies George Cronkite, Hermann J Enzenhofer, John Holmes & Jim Krivanek Split-beam system How far away YES! How big YES! (Acoustic size) Which way it s going..yes! How many YES! History Originally used split-beam technology ( ) Ideal site because fish actively migrated near shore on both banks Qualark was used to develop the methodology for producing estimates in rivers Specialized equipment was designed, constructed and tested at Qualark A test fishing program was done in conjunction with the acoustic program Using split-beam technology Can be complex Requires a high level of acoustic expertise Technology not easily transferred to others What is a Sonar (Hydroacoustic) system? Uses sound in water to detect objects. All hydroacoustic systems use electrical signals to an underwater transducer that transmits sound waves out into the water. The echoes of sound return to the transducer and are converted back to electric signals and processed by the hydroacoustic system.

2 Free-standing weir operated in 1993 Raw echoes received from fish actively migrating Right bank modifications in 1994 Tracking algorithm applied Addition of an acoustic sand bag ramp Automated fish deflection weir and track system Creating the ideal site Fish tracks can be edited

3 Left bank modified for 1995 season Qualark Creek site re-activated in 2008 Applying DIDSON technology at Qualark Creek on the Fraser River, BC Yale First Nation contribute funds for low water operation in February1999 What is a DIDSON? Dual-Frequency Identification Sonar DIDSON uses an array of sonar beams to produce digital images of objects in water. Called an acoustic camera because it uses lenses to focus beams. Able to visually count fish and determine direction of travel. Qualark Creek site de-activated before 1999 season starts

4 Work begins at Qualark in February 2008 What can you see with a DIDSON? Coverage for both banks DIDSON technology tested on the Horsefly River 2005 Right bank Left bank 35 m track 30 m track DIDSON on Pole Mount How many can be counted? Horsefly River 2005 (7800 fish/hr)

5 Data processing Manual Counting All files replayed and counted using tally whackers. Replay rate dependent on density and user confidence. Randomly chose 17% of the previous 24 hr passage for recounting by senior staff. Expand counts to give passage per hour Transducer-to-weir bracket Pole mount stabilizer Pivot arm Pole mount (slide & receiver) Transducer plate 90 Hinged bracket DIDSON (rear view) Temporal sub-sampling FLOW DIDSON Weir Pole mount Producing the daily acoustic count Coverage with -30 horizontal roll Coverage 20 cm below water surface 2.4 m -30

6 High passage rate (36,000/hr) Background subtraction Count range bins (Zoom) How do we count high passage?

7 Seal 18,000/hr Seal/sturgeon Interesting images seen on site Beaver Sturgeon

8 Test fishing Sturgeon/salmon Estimate species composition of the acoustic estimate Test for presence/absence of fish DNA, scale, length, weight, sex Run timing (racial analysis) Daily drift sequence Unknown? Daily consecutive series of drifts done with 4, 4, 5, 5, 6 and 8 inch mesh. Each net 100ft x 70 mesh hang. Each drift duration approximately 4 min to cover the 700 meter river stretch. AM drift series using 4, 5, and 6 inch mesh PM drift series using 4, 5, and 8 inch mesh. AM & PM drift series alternated Drift gillnet Drift net

9 Sample where you work Why you need to sample! Conclusions Proper site selection is the key to success! Qualark is ideal for enumeration because fish are near shore Investing in infrastructure simplifies site operations. DIDSON technology preferred over split-beam due to ease of operation and visual interpretation of fish behaviour Manual count processing is sufficient for high data volumes Test fishery gives good information but possibly the data could be interpreted in other ways for determining species composition DFO and others are interested in studying the test fishery data to establish how best to apply the data to determine species composition We believe the acoustic estimate of salmon is fundamentally sound