Exploration of DIDSION Exploration of DIDSION Technology; Spawning Technology; Spawning

Site, Site, Confirmation/CharacterizatConfirmation/Characterizat

ion and Spawner ion and Spawner Behaviour ObservationBehaviour Observation

May 26 – 29, 2009

Pilot Explorations on the Pilot Explorations on the Nechako RiverNechako River

Purpose(s) Purpose(s)

• Interested in spawning site selection Interested in spawning site selection (confirming)(confirming)– Information habitat restoration planning reInformation habitat restoration planning re– Depth, velocity, substrateDepth, velocity, substrate

• Spawning behaviour – poorly documentedSpawning behaviour – poorly documented– General interest General interest

• Deep water with poor visibility – possible Deep water with poor visibility – possible utility in DIDSON technology?utility in DIDSON technology?

What’s a DIDSON?What’s a DIDSON?•Relatively new technology

– Dual-Frequency Identification Sonar

•DIDSON operates at 2 frequencies, 1.8 MHz or 1.0 MHz, - forms 96 beams spaced 0.3° apart, or 48 beams spaced 0.6° apart

• Images out to 12 m at 1.8 MHz and 40 m at 1.0 MHz. Update rate between 5-27 frames/s.

•Sufficiently high resolution and rapid refresh rate that it can substitute for optical systems in turbid or deep water

Commonly Utilized in Salmon Commonly Utilized in Salmon Spawner Enumeration Programs - Spawner Enumeration Programs -

StationaryStationary

Consumes 30 Watts – need a generator

DIDSON

Video

12o

horizontal

DIDSON sonar has large angle beam and bottom subtraction

Data Monitoring and Data Monitoring and InterpretationInterpretation

Not typically utilized as a mobile device

Imaging ExamplesImaging Examples

•http://www.youtube.com/watch?v=3XxL73-23qQ

•http://www.soundmetrics.com/industries-served/aquatic-life/fish-surveys

First Challenge – Not typically First Challenge – Not typically utilized in mobile deploymentutilized in mobile deployment

• Compare with echogramCompare with echogram

• Much more intuitiveMuch more intuitive

Video Clip

Imaging CapturedImaging Captured

Learning and Learning and RecommendationsRecommendations•A larger and more stable boat should be

employed in future work. The instability of the boat affected the ability to insonify a moving target consistently.

•The boat-mount system should be adjustable to port or starboard

•An improved anchor system – dual point

Learning and Learning and RecommendationsRecommendations•During daylight hours, need a mechanism

to shade PC screen

•Future work should be conducted throughout the day and night for a longer overall time period (recommend at least 10 days to allow for maximum opportunity to locate potential spawning sites and spawners – in coordination with telemetry).

Existing Management Existing Management ProcessProcess

HydroacoustiHydroacousticscs

In-season In-season Test fishingTest fishing

In-seasonStock-specific

abundance estimatesIn-season

Stock-specific

escapementestimates

Preseason Modeled Estimates

Exploit

TerminalStock-specific

abundance estimates

Probe Gone BAD!

Daily Sampling Effort (after the 1998 optimization):15 hours of mobile + 6 hours of stationary samplings.

PSC’s Mission Echo-Sounding Vessel: Rita

MobileSampling(from N =>S)

StationarySamplingoff the south bank

Acoustically Sampled Fish by 15 Hours of Mobile Sounding. Estimated Statistic: Fish Density

Acoustically Sampled Fish by 9 sets of Stationary Sounding.Estimated Statistic: Duration-in-beam (Fish Speed)

S C N

Problem:Problem:• All of US catch allocation occurs outside All of US catch allocation occurs outside

Fraser river (most 2-4 days seaward of Fraser river (most 2-4 days seaward of MissionMission

• 80% of Canadian catch allocation occurs 80% of Canadian catch allocation occurs 5-8 days seaward of Mission5-8 days seaward of Mission

• The design of run size assessment The design of run size assessment programs is ultimately defined by programs is ultimately defined by the tradeoffs between desired the tradeoffs between desired certainty, acceptable risks, and certainty, acceptable risks, and costs.costs.

Run-size Certainty-Run-size Certainty-Catch Allocation Catch Allocation

MismatchMismatch

The Mission Split-Beam Sampling System(under development)

Total Upstream FishFlux = SouthBank Flux + Mobile Flux

Upstream Fish-Fluxby Mobile System

Upstream Fish-Fluxby SouthBank System

100m 300m

Weaverfreshwater growth zone

In a Chilko fish, this zone wouldbe smaller

Racial analysis: Racial analysis: the why and how (so far)the why and how (so far)

1. Our rationale

2. How scales are used

3. Other methods (incl. DNA)

Racial analysis: Racial analysis: the why and how (so far)the why and how (so far)

1. Our rationale

2. How scales are used

3. Other methods (incl. DNA)