IInvestigating high frequency nvestigating high frequency underwater vessel noise and underwater vessel noise and

potential masking of killer potential masking of killer whale echolocation clickswhale echolocation clicks

Tim HuntTim HuntBeam Reach Marine Science and Sustainability SchoolBeam Reach Marine Science and Sustainability School

Fall 2007 - beamreach.org/071 Fall 2007 - beamreach.org/071 Flinders University of South AustraliaFlinders University of South Australia

IntroductionIntroduction The Southern Resident Killer WhaleThe Southern Resident Killer Whale

EndangeredEndangered

Increase in WW boats over the yearsIncrease in WW boats over the years ‘‘98-’05 consistently 20 vessels within ½ mile radius98-’05 consistently 20 vessels within ½ mile radius

Erbe (2002) - underwater noise study of WW Erbe (2002) - underwater noise study of WW boatsboats

My study expand on aspects of this – boater cooperation!My study expand on aspects of this – boater cooperation!

Look at specific vessel types using HF Look at specific vessel types using HF hydrophonehydrophone

Sample up to 30 kHz at 44.1k sampling rate - HF samples Sample up to 30 kHz at 44.1k sampling rate - HF samples up to 90 kHz at 192k sampling rate WOW!up to 90 kHz at 192k sampling rate WOW!

Not done before measuring vessel noise new & novel!Not done before measuring vessel noise new & novel!

Echolocation clicks in these higher frequenciesEcholocation clicks in these higher frequencies Compare with boat noise to infer possible masking?Compare with boat noise to infer possible masking?

Relate to County Law and WW guidelinesRelate to County Law and WW guidelines

Spot the OrcaSpot the Orca

Echolocation clicks in killer Echolocation clicks in killer whaleswhales

What is an echolocation click? What is an echolocation click? What is it used for?What is it used for? What does it sound like?What does it sound like? High frequency, range up to 80 kHzHigh frequency, range up to 80 kHz

Need a device to sample up to these high Need a device to sample up to these high frequencies…frequencies…

Killer whale audiogramKiller whale audiogram

2 orcas in captivity

Attached probes to melon

Measured ABR

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dB re 1µ Pa_/Hz

Physiologicalthreshold

Simplified from Szymanski et al. 1999

Most sensitive18-42 kHz

Questions posedQuestions posed Is a vessel cruising at high speeds (>18 Is a vessel cruising at high speeds (>18

knots) at 400m “louder” that a vessel slow knots) at 400m “louder” that a vessel slow motoring at low speeds (5-8 knots) at 100m?motoring at low speeds (5-8 knots) at 100m?

Is there is a difference in frequency Is there is a difference in frequency spectrum levels between different vessel spectrum levels between different vessel propulsion types?propulsion types?

To what degree, if at all, do different vessel To what degree, if at all, do different vessel types mask echolocation clicks?types mask echolocation clicks?

MethodsMethods Two speeds, two distances (relates to Two speeds, two distances (relates to

SJ County Law and BWW guidelines)SJ County Law and BWW guidelines) Slow Motor (SM) = speed of 5-8 knotsSlow Motor (SM) = speed of 5-8 knots

When within 400m of whalesWhen within 400m of whales Cruise (C) = 18-25 knotsCruise (C) = 18-25 knots

When further than 400mWhen further than 400m Test SM and C at Test SM and C at

100m and 400m100m and 400m Record echolocation clicksRecord echolocation clicks

Study siteStudy siteSample sites

MaterialsMaterials

SamplingSampling

Vessels measuredVessels measured Business names kept anonymous, vessel Business names kept anonymous, vessel

classification based on propulsion systemclassification based on propulsion system Twin Inboard 400HP BioDieselTwin Inboard 400HP BioDiesel Twin Outboard 150HPTwin Outboard 150HP Surface PiercingSurface Piercing Twin Inboard DieselTwin Inboard Diesel Jet DriveJet Drive

Also measured Also measured Gato Verde Gato Verde catamaran, Washington State catamaran, Washington State Ferry, cargo ship and dinghyFerry, cargo ship and dinghy

ResultsResultsTwin Inboard Diesel

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dB

SM 100m

C 140m

SM 400

C 400m

Twin Outboard 150 HP

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kHz

dB re 1µPa_/Hz

SM 100m

C 100m

SM 400m

C 400m

Surface Piercing

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kHz

dB re 1µPa_/Hz

SM 100m

C 100m

C 400m

Twin Inboard 400HP BioDiesel

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kHz

dB

SM 100m

C 100m

SM 400m

C 400m

Jet Drive

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kHz

dB re 1µPa_/Hz

SM 140m

C 100m

C 400m

Background

More ResultsMore Results

WSF and Cargo Ship

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dB re 1µPa_/Hz

CS 900m

CS 430m

WSF 1000m

WSF 480m

Gato Verde catamaran

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kHz

dB

Electric Motor100m

Generator 100m

Generator 400m

Even more resultsEven more results

No sig. difference b/w No sig. difference b/w

SM 100m & C 400mSM 100m & C 400m

3/5 vessels had 3/5 vessels had difference in RL of 10 difference in RL of 10 dB or greater (C dB or greater (C 400m > SM 100m)400m > SM 100m)

Twin OB 150HP Twin OB 150HP oppositeopposite

Surface Piercing 1dB Surface Piercing 1dB

difference difference

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Twin IB400HP

BioDiesel

Twin IBDiesel

Twin OB150HP

SurfacePiercing

Jet Drive

Received Level (dB re 1µPa_/Hz)

Slow Motor 100m

Cruise 400m

A killer whale A killer whale echolocation clickecholocation click

What in the bloody hell do all these lines mean?!What in the bloody hell do all these lines mean?!

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EcholocationclickClick + 1SD

Click - 1SD

Echo of a click

KWAudiogram

Sounds above echo, clicks masked

Sounds below echo, clicks heard

Vessels vs. click vs. Vessels vs. click vs. audiogramaudiogram

Higher spectrum level = higher mean RL?

NO!

Slow Motor @ 100m

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dB re 1µPa_/Hz

SurfacePiercing

Tw in OB150HP

Tw in IB400HPBioDieselTw in InboardDiesel

ElectricMotor

KWAudiogram

Echolocationclick

Echo of aclick

Both 115.5 dB

Cruise @ 400m

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kHz

dB re 1µPa_/Hz

SurfacePiercing

Tw in OB150HP

Tw in IB400HPBioDiesel Tw in IBDiesel

Dinghy

KWAudiogram

Echolocationclick

Echo of aclick

2 vessels below echo

All vessels above echo

MASKING

DiscussionDiscussion

Peaks in Jet Drive vessel, & Twin IB Peaks in Jet Drive vessel, & Twin IB 400HP BioDiesel. Mmm….400HP BioDiesel. Mmm….

What is a significant dB difference?What is a significant dB difference? 6 dB = twice as loud in human ear6 dB = twice as loud in human ear

Gato VerdeGato Verde – EM vs G, just propeller – EM vs G, just propeller noise?noise?

Echolocation click mean Echolocation click mean Bimodal distribution 10-50 kHzBimodal distribution 10-50 kHz

Similar to Au Similar to Au et al.et al. 2003 2003

Things to think aboutThings to think about

KW Audiogram – is it representative of wild KW Audiogram – is it representative of wild orcas?orcas? Individual tested reportedly partially deafIndividual tested reportedly partially deaf

Busy day in the Haro Strait - individual vessel Busy day in the Haro Strait - individual vessel noise might be indistinguishable to an orcanoise might be indistinguishable to an orca

Hard to quantify difference in vessel typeHard to quantify difference in vessel type Can’t really say one is better/worse than anotherCan’t really say one is better/worse than another Can’t really say one is having more/less effect on Can’t really say one is having more/less effect on

echolocationecholocation

Personal observations – orcas swimming Personal observations – orcas swimming under ferries & riding bow wave of cargo shipunder ferries & riding bow wave of cargo ship Does noise really bother them?Does noise really bother them?

Improvements/Future Improvements/Future researchresearch

Make sample size bigger!Make sample size bigger! Sample vessels on separate daysSample vessels on separate days More clicks, perhaps infer distance?More clicks, perhaps infer distance?

Measure vessels at more distances, build Measure vessels at more distances, build database, compare, infer, legislate?database, compare, infer, legislate?

Engine noise? Propeller noise? Engine noise? Propeller noise? Combination?Combination? Test these to aid in minimising underwater Test these to aid in minimising underwater

noisenoise More research = better understandingMore research = better understanding

If we can lower noise of If we can lower noise of thisthis

And better understand And better understand thisthis

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EcholocationclickClick + 1SD

Click - 1SD

Echo of a click

KWAudiogram

Then we can minimise Then we can minimise impact on thisimpact on this

AcknowledgementsAcknowledgements

Beam Reach and all the crewBeam Reach and all the crew Boat operators for driving-byBoat operators for driving-by Whale watch operators for the good Whale watch operators for the good

times on the radiotimes on the radio Team VaTo for putting up with my Team VaTo for putting up with my

singingsinging Flight Of The Conchords for musical Flight Of The Conchords for musical

comic relief during times of hardshipcomic relief during times of hardship

Questions?Questions?