Qualark Creek. History

Transcription

1 Qualark Creek Dept. Fisheries & Oceans Canada Applied Technologies George Cronkite, Hermann J Enzenhofer, John Holmes & Jim Krivanek 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 t and tested t at Qualark A test fishing program was done in conjunction with the acoustic program 1

2 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. Single beam system (fish finder) Not particularly good for counting fish! How far away YES! How big.no! Which way it s going..no! 2

3 Split-beam system How far away YES! How big YES! (Acoustic size) Which way it s going..yes! How many YES! Using split-beam technology Can be complex Requires a high level of acoustic expertise Technology not easily transferred to others 3

4 Raw echoes received from fish actively migrating Tracking algorithm applied 4

5 Fish tracks can be edited Free-standing weir operated in

6 Right bank modifications in 1994 Addition of an acoustic sand bag ramp Automated fish deflection weir and track system Creating the ideal site 6

7 Left bank modified for 1995 season Yale First Nation contribute funds for low water operation in February1999 7

8 Qualark Creek site de-activated before 1999 season starts Qualark Creek site re-activated in

9 Applying DIDSON technology at Qualark Creek on the Fraser River, BC 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. 9

10 What can you see with a DIDSON? DIDSON technology tested on the Horsefly River

11 How many can be counted? Horsefly River 2005 (7800 fish/hr) Work begins at Qualark in February

12 Coverage for both banks Right bank Left bank 35 m track 30 m track DIDSON on Pole Mount 12

13 Transducer-to-weir bracket Pole mount (slide & receiver) Pole mount stabilizer Pivot arm Transducer plate 90 Hinged bracket DIDSON (rear view) FLOW DIDSON Weir Pole mount 13

14 Coverage with -30 horizontal roll Coverage 20 cm below water surface 2.4 m -30 Manual Counting Data processing 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 14

15 Temporal sub-sampling % Confidence intervals (%) Sampling time (min h -1 ) Producing the daily acoustic count Daily Count by Species Sockeye, Chinook and Coho Pink Jun Jun Jul Jul Jul Jul Jul Jul Jul Jul Aug Aug Aug Aug Aug Aug Aug Aug Sep Sep Sep Sep Sep Sep Sep Oct-09 Date Sockeye Chinook Adults Chinook Jacks Coho Pink 15

16 Expand ded Upstream Count Jun Jun Jul Jul Jul Jul Jul Aug Aug Aug Aug Aug-09 Date 03-Sep Sep Sep Sep Sep-09 END RB LB Total Cumulative Count by Species Sockeye, Chinook and Coho Pink Jun Jun Jul Jul Jul Jul Jul Jul Jul Jul Aug Aug Aug Aug Aug Aug Aug Aug Sep Sep Sep Sep Sep Sep Sep Oct-09 Date Sockeye Chinook Adults Chinook Jacks Coho Pink 16

17 How do we count high passage? High passage rate (36,000/hr) 17

18 Background subtraction Count range bins (Zoom) 18

19 18,000/hr Interesting images seen on site 19

20 Drift net Test fishing Estimate species composition of the acoustic estimate t Test for presence/absence of fish DNA, scale, length, weight, sex Run timing (racial analysis) 23

21 Daily drift sequence Daily consecutive series of drifts done with 4, 4¾, 5¼, 5¾ ¾, 6¾and8inchmesh 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, 5¼, and 6 ¾ inch mesh PM drift series using 4¾, 5 ¾, and 8 inch mesh. AM & PM drift series alternated Drift gillnet 24

22 Sample where you work Why you need to sample! 25

23 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 26