Tim hunt beam reach marine science and sustainability school fall 2007 beamreach 071
This presentation is the property of its rightful owner.
Sponsored Links
1 / 24

Tim Hunt Beam Reach Marine Science and Sustainability School Fall 2007 - beamreach/071 PowerPoint PPT Presentation


  • 53 Views
  • Uploaded on
  • Presentation posted in: General

I nvestigating high frequency underwater vessel noise and potential masking of killer whale echolocation clicks. Tim Hunt Beam Reach Marine Science and Sustainability School Fall 2007 - beamreach.org/071 Flinders University of South Australia. Introduction.

Download Presentation

Tim Hunt Beam Reach Marine Science and Sustainability School Fall 2007 - beamreach/071

An Image/Link below is provided (as is) to download presentation

Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author.While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server.


- - - - - - - - - - - - - - - - - - - - - - - - - - E N D - - - - - - - - - - - - - - - - - - - - - - - - - -

Presentation Transcript


Tim hunt beam reach marine science and sustainability school fall 2007 beamreach 071

Investigating high frequency underwater vessel noise and potential masking of killer whale echolocation clicks

Tim HuntBeam Reach Marine Science and Sustainability SchoolFall 2007 - beamreach.org/071

Flinders University of South Australia


Introduction

Introduction

  • The Southern Resident Killer Whale

    • Endangered

  • Increase in WW boats over the years

    • ‘98-’05 consistently 20 vessels within ½ mile radius

  • Erbe (2002) - underwater noise study of WW boats

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

  • Look at specific vessel types using HF hydrophone

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

    • Not done before measuring vessel noise new & novel!

  • Echolocation clicks in these higher frequencies

    • Compare with boat noise to infer possible masking?

  • Relate to County Law and WW guidelines


  • Spot the orca

    Spot the Orca


    Echolocation clicks in killer whales

    Echolocation clicks in killer whales

    • What is an echolocation click?

    • What is it used for?

    • What does it sound like?

    • High frequency, range up to 80 kHz

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


    Killer whale audiogram

    2 orcas in captivity

    Attached probes to melon

    Measured ABR

    Most sensitive

    18-42 kHz

    Simplified from Szymanski et al. 1999

    Killer whale audiogram


    Questions posed

    Questions posed

    • Is a vessel cruising at high speeds (>18 knots) at 400m “louder” that a vessel slow motoring at low speeds (5-8 knots) at 100m?

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

    • To what degree, if at all, do different vessel

      types mask echolocation clicks?


    Methods

    Methods

    • Two speeds, two distances (relates to SJ County Law and BWW guidelines)

    • Slow Motor (SM) = speed of 5-8 knots

      • When within 400m of whales

    • Cruise (C) = 18-25 knots

      • When further than 400m

    • Test SM and C at

      100m and 400m

    • Record echolocation clicks


    Study site

    Sample sites

    Study site


    Materials

    Materials


    Sampling

    Sampling


    Vessels measured

    Vessels measured

    • Business names kept anonymous, vessel classification based on propulsion system

      • Twin Inboard 400HP BioDiesel

      • Twin Outboard 150HP

      • Surface Piercing

      • Twin Inboard Diesel

      • Jet Drive

    • Also measured Gato Verde

      catamaran, Washington State

      Ferry, cargo ship and dinghy


    Results

    Results


    More results

    More Results


    Even more results

    Even more results

    • No sig. difference b/w

      SM 100m & C 400m

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

    • Twin OB 150HP opposite

    • Surface Piercing 1dB

      difference


    A killer whale echolocation click

    Sounds above echo,

    clicks masked

    Sounds below echo,

    clicks heard

    A killer whale echolocation click

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


    Vessels vs click vs audiogram

    2 vessels below echo

    All vessels above echo

    Both 115.5 dB

    Vessels vs. click vs. audiogram

    MASKING

    Higher spectrum level = higher mean RL?

    NO!


    Discussion

    Discussion

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

    • What is a significant dB difference?

      • 6 dB = twice as loud in human ear

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

    • Echolocation click mean

      • Bimodal distribution 10-50 kHz

        • Similar to Au et al. 2003


    Things to think about

    Things to think about

    • KW Audiogram – is it representative of wild orcas?

      • Individual tested reportedly partially deaf

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

    • Hard to quantify difference in vessel type

      • Can’t really say one is better/worse than another

      • Can’t really say one is having more/less effect on echolocation

    • Personal observations – orcas swimming under ferries & riding bow wave of cargo ship

      • Does noise really bother them?


    Improvements future research

    Improvements/Future research

    • Make sample size bigger!

      • Sample vessels on separate days

      • More clicks, perhaps infer distance?

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

    • Engine noise? Propeller noise? Combination?

      • Test these to aid in minimising underwater noise

    • More research = better understanding


    If we can lower noise of this

    If we can lower noise of this


    And better understand this

    And better understand this


    Then we can minimise impact on this

    Then we can minimise impact on this


    Acknowledgements

    Acknowledgements

    • Beam Reach and all the crew

    • Boat operators for driving-by

    • Whale watch operators for the good times on the radio

    • Team VaTo for putting up with my singing

    • Flight Of The Conchords for musical comic relief during times of hardship


    Questions

    Questions?


  • Login