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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0 10 20 30 40 50 60 70 80 90 100
kHz
dB re 1µPa_/Hz
SM 100m
C 100m
SM 400m
C 400m
Surface Piercing
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0 10 20 30 40 50 60 70 80 90 100
kHz
dB re 1µPa_/Hz
SM 100m
C 100m
C 400m
Twin Inboard 400HP BioDiesel
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0 10 20 30 40 50 60 70 80 90 100
kHz
dB
SM 100m
C 100m
SM 400m
C 400m
Jet Drive
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0 10 20 30 40 50 60 70 80 90 100
kHz
dB re 1µPa_/Hz
SM 140m
C 100m
C 400m
Background
More ResultsMore Results
WSF and Cargo Ship
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kHz
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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dB re 1µPa_/Hz
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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dB re 1µPa_/Hz
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?