How critical is the impact of underwater noise on marine mammals??

How critical is the impact of underwater noise on marine

mammals??

Patrick MillerScottish Oceans InstituteUniversity of St Andrews, Scotland

1Dan McSweeney

Over the past century, humans started producing sound in the ocean that may

interfere with marine mammals

Sou

rce

Leve

l (dB

)

100

150

200

250

300

0.001 0.01 0.1 1 10 100 1000

Earthquake

Blue Whale

Lightning

Frequency (kHz)

Sperm Whale

HumpbackDolphin Whistle

Dolphin ClickSnapping Shrimp

TNT Explosion

Air GunSonarLFA

ShipPile Drive Sonar

Modes of Impact

Intense sounds can cause direct physical injury

In most other cases, it is assumed that hearing is the most sensitive organ and that effects are mediated through hearing

Underwater Audiograms

Frequency (kHz)

Lobster Fish DolphinPorpoise

Whales? ??0.01 0.1 1 10 100 1000

40

60

80

100

120

140

160S

ound

Pre

ssur

e Le

vel (

dB re

1 µ

Pa)

Animals use a broad spectrum of frequencies

Zones of Noise Influence

InjuryHearing LossAvoidanceBehavioral disturbanceAudibility (could occur whenever sound level above ambient noise)

Adapted from Richardson and Malme 1995

acoustic criteria for injuryNeed method that is

u safe for subjectsu pre-cautionary as an indicator

During 1990s the US Office of Naval Research sponsored a major research program to measure levels of sound that reduce sensitivity to sound temporarily

– Temporary Threshold Shift

Measuring Temporary Threshold Shift in Marine Mammals

Measure the threshold at which animal just detects a soundExpose animal to loud soundMeasure hearing again to see if threshold shifted

-0.25

-0.2

-0.15

-0.1

-0.05

0

0.05

0.1

0.15

0.2

0 5 10 15 20 25 30

Envelope Following

CourtesyP. Nachtigall

Nachtigall Univ of Hawaii

Summary of TTS for captive odontocetesCourtesy J. Finneran

Unexpected Source of Injury

Just as TTS data were becoming available…

Evidence (1998-2000) that beaked whales may strand during naval sonar exercises

Cause of sonar-related strandings is unknown

But likely to be caused by exposures below TTS levels

Only known lethal effect of sound: mass strandings of beaked whales

coincident with sonar exercises

9

10

11

0600

0900

1200

1500

1800

RUNS Strandings

9

10

11

D’Amico 1998 Saclantcen M-133

Mass strandings of Beaked Whales coincident with naval sonar exercises

>10 Beaked whales, especially Ziphius cavirostrisand Mesoplodon sp. strand within a few hours in dispersed groupings over tens of km of shore.

Reported to coincide with naval maneuvers off Greece (1), Canary Islands (7), Italy (2), Bahamas (1), Madeira (1) [US Marine Mammal Commission Beaked Whale Workshop Report]

All known cases involve ships with mid-frequency (MF: 2-10 kHz) military sonars

Distribution of Blainville's Beaked Whale ClicksBefore, During, After Active Sonar Operations

Before During After

EFFECT RANGE ~10 KM. CORRESPONDING RECEIVED LEVEL ~ 155 dB (235 – 20 log (10000))

Tyack et al., 2011

14

behavioural effects:what are the consequences?

Avoidance is particularly difficult to interpret as no life function is directly affected.

Avoidance may be most likely when consequences are negligible (Beale & Mohaghan, 2004; Frid & Dill, 2002).

Behavioral Disruption of Biologically Significant activities that can be

Related to Adverse ImpactBasic issues are demographic – effects on

growth, survival, and reproductionGrowth: Feeding and energeticsSurvival: strandings

Evaluating significance of disruption of foraging in a deep diving sperm whale

Development of digital tag• Records: sound and 3-D movement• Suction-cup

attachment

Designed and built by Mark Johnson

Dtag Attachment

Whale depth (m)

StartExposure

Seismic Vessel Approaches Tagged Whale

Seismic Vessel

Min range between seismic vessel and whale = 8 km

3

45

1

2

WhaleTrack

ObservationVessel

6

7

Echolocation buzzes indicate prey capture attempts

Clicks of diving sperm whales

creak (ICI ~ 0.3 to 0.02s) pause (2-10s)clicks (ICI ~ 0.4-1.5s)

regular clicking creakpause

Griffin, 1974

Miller et al., 2004

Change in Buzz Rate with Range

Miller et al., 2009




What are the effect thresholds?

23

management need

risk of negative outcome depends on sonar dose

“All substances are poisons...

The right dose differentiates a poison and a remedy.”

Paracelsus (1493-1541)

Developing Acoustic Criteria for behavioural disturbance

Mid-frequency cetacean responses to non-pulses

Southall et al., 2007

Application of Phase-I medical trial techniques to explore dose-response

relationships for behavioural effects of sonar on free-ranging whales

25Dan McSweeney

26

The 3S dose-response study

Use experiments to help specify the likelihood of behavioural response as a function of sonar dose

27

Experimental Methods

Socrates source

0.) Find whales

1.) Attach Dtagmovements & sounds

2.) Measure behaviourbeforeduring sonar and control exposuresafter

3.) Mitigation proceduresreduce risk of harm

11--2 kHz2 kHz 66--7 kHz7 kHzLFASLFAS MFASMFAS214 dB214 dB 199 dB re 1199 dB re 1PamPam

28

Sonar dose-escalation: a tool to specify response thresholds

29

3S program datasets

Dose-escalation species:- killer whales (N=4)- long-finned pilot whales (N=6)- sperm whales (N=4)- minke whales (N=1)- Northern bottlenose whales

3S: report of experiments

Details outcome of each experiment:

- set of data plots- descriptive summary

Available at: http://soi.st-andrews.ac.uk/

30

31

Focus on killer whale

32

exposure 4-13S-09 oo09_144a,b

33

phase I clinical trialsin medical research

Phase I trials seek to identify toxicity of drug1.) patient is given a dose2.) physician determines ‘grade of response’

‘update … dose-response relationship as observations …become available’*

- fit ongoing data to dose-response model(using Baysian or Maximum Likelihood approaches)

*O’Quigley et al. 1990 Biometrics 46:33-48#Simon et al., 1997 J Nat. Cancer Inst. 89: 1138-1147

34

onset of avoidanceby killer whales

Avoidance during travel

Stopped feeding

Calf separated from group

Stopped feeding

Avoidance during travelDuring travel

Thresholds:onset of avoidance

35

4-14-2

4-3

1-1

2-1

3-13-3 3-2

whale population has distribution of thresholds, each whale is a sample from population:

measured factors (frequency, order) influence thresholds:

unexplained variance of individual response thresholds

Bayesian dose-response model

Dose-response curve

50% likelihood of avoidance4km distance / 140 dB SPL

39

Do such responses matter?

Ample data indicates that marine mammals can be affected by noise.

But,How serious is this problem, really???

A recent IWC report (Read et al., 2003) indicates that worldwide, fisheries kill several hundred thousand cetaceans as bycatch each year.

Avoidance response is an indicator of habitat degradation

How much of the habitat is impacted?What proportion of the population is impacted?

Does avoidance interfere with use of resources that make habitat important?

Consider CONSEQUENCES for affected animals1.) social behaviour / care 2.) feeding rates body condtion

Summary- Humans alter the acoustic environment of the sea- Some marine mammals may be killed or injured,- But, the most substantial impacts are likely to be

more subtle but pervasive effects on populations and ecosystems

- How to manage / mitigate this risk of impact?

42

Thanks to:

Funded by:Funded by:

ALL ships’ crews and science teamsDtag: Mark Johnson, Tom Hurst, Alex Bocconcelli

PETER TYACK, Paul Wensveen, Ricardo Antunes, Ana Catarina Alves,Filipa Samarra, Sanna Kuningas, Petter Kvadsheim, Lars Kleivane, Frans-Peter Lam, Michael Ainslie, Len Thomas, Kagari Aoki, Yuuki Watanabe, Daniel Crocker, Patrick Robinson, Martin Biuw, Daniel Costa, Nobuyuki Miyazaki, Mike Fedak, and more

Norwegian Animal Research Authority (Permit No. 2004/20607 and S-2007/61201)U of St Andrews Animal Welfare and Ethics CommitteeWHOI Institutional Animal Care Use Committee

How critical is the impact of underwater noise on marine mammals??

Documents

Transcript of How critical is the impact of underwater noise on marine mammals??