Jonathan Gordon
~16 “management units”
SCANS I 1994
SCANS II 2005 (386,000 )
Difficult to sight
Very vocal with highly characteristic clicks
Favours the use of passive acoustics for survey
Both Static and Mobile
Harbour Seal (Phoca vitulina)
Rapid increase in Wadden Sea
At the same time many Scottish colonies are declining
A Dynamic and Changing Population
Come ashore to haul out. Available to be counted and for Telemetry
Phases in the Life of Wind Farm
 Assessment (Low level over years)
 Enhanced vessel traffic
 Some geophysical survey
 Construction (months to years)
 Pile driving (and other construction methods)
 Greatly elevated vessel activity
 Operation (decades)
 Turbine noise
 Maintenance traffic
 Physical presence of piles and foundations ?+ve?
 Effects on fishing ?+ve?
 Decommissioning and Removal (months to years)
 Explosives or other cutting technologies
 Possible issues with removal of “ artificially enhanced”
environment?
Types of Effect and Concerns
 Noise: Physical Effects from High Level Sound

Auditory system most sensitive to sound and most likely to be damaged
 Noise: Perceptual, Masking


Unlikely to be significant
Little spectral overlap with echolocation signals
 Noise: Behavioural 
Disturbance, disruption of important activities and habitat exclusion  Habitat Change  Could be +ve or ‐ve
Assessing Hearing Damage Risk
 Sound exposure criteria –
 What levels are unacceptable or dangerous
 Temporary Threshold Shift (TTS)
 Not biologically important but and indicators for
 Permanent Threshold Shift (PTS)
 Permanent loss of sensitivity
 Likely significant for acoustically oriented animals such as marine mammals
Southall et al. (2008)
•Summarises conclusions from a series of expert workshops
•Clear explanation of processes and assumptions .
•Framework that can be updated with new knowledge
Lucke et al. (2009)
Important Recent
Study
Measured Porpoise
Vulnerability to Airgun
Pulses (proxy for piling
noise)
Right species right
noise type
TTS @ SEL
164dB re 1 Pa2 s. Need similar studies for other species
Assessing Hearing Damage Risk
 Sound exposure criteria –
 What levels are unacceptable or dangerous
 Source Levels
Relatively easy to Measure but piles getting larger so often source levels have to be extrapolated for EIAs
Cumulative Exposure: SEL
What is the sound field?
 Source level and Propagation conditions
How do animals move through it
Simple model of animal moving in a sound field
Calculate cumulated SEL through piling event
Does is exceed threshold for PTS?
Establish Maximum “starting range”
Animal responsive movements is a critical poorly known parameter
Risks of Hearing Damage: Summary
 Very large uncertainties remain about the risks of PTS from this type of acoustic exposure
 Poor information on propagation conditions and animal movements adds substantially to uncertainty
 Safety Zones on the order of several hundreds of meters may be necessary to minimise the risk of hearing damage
Risks of Hearing Damage: Mitigation
 Mitigation could reduce this risk
 Visual and acoustic searches, traditional method

expensive and possibly not very effective especially with large exclusions zones
 Aversive sounds may be more effective

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
Move animals out of the exclusion zone before piling starts
BioConsult, encouraging results with porpoises, (Brandt et al 2012)
SMRU on‐going work involving at sea CEE with seals
Behavioural Responses and Disturbance
 We expect behavioural responses to be highly variable‐ and they are.
 Proven difficult to predict responses to particular sound types
 but we can measure them relatively easily
 Need to collect a substantial samples to provide adequate statistical power
 Most effective research approaches differ between species
PODS to Assess Porpoises Disturbance During Construction
 Porpoises are highly vocal producing characteristic clicks  Allows long term monitoring with simple autonomous detectors and loggers  The most widely used example is the POD  Invaluable tool, extensively used at wind farms.
 Low cost long term monitoring providing high power to detect change.  Several projects have applied this technique and all have shown changes in detection rate around the time of piling
 Reduction in detection rate (porpoise positive minutes).
 Increase in “waiting time” between acoustic encounters
Monitoring with PODs at Horns Rev II (Brandt et al., 2011. MEPS)
FINO 3: Day before Piling
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FINO 3: Porpoise densities 30.7.08
FFH-Gebiet-Grenze
AWZ-Grenze
Waldichten 30.07.08
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Slide Courtesy of Georg Nehls FINO3:
aerial surveys: Day of Piling
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FINO 3: Porpoise densities 31.7.08 (piling)
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Slide Courtesy of Georg Nehls FINO3:
aerial surveys: 16 Days after Piling
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FINO 3: Porpoise densities 16.8.08
FFH-Gebiet-Grenze
AWZ-Grenze
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Slide Courtesy of Georg Nehls Disruptive Effects Could Occur Outside any “Exclusion Zone”
Reduced Density
Animals Displaced into this area increased density and competition
Seals: Behavioural Responses During Construction
 Few detailed studies showing effects on behaviour and distribution at sea from telemetry
 Tagged seals don’t always go where you want them to at the time you want
 Large scale telemetry project currently underway in the Wash (SMRU), should provide interesting results
 On the basis of hearing sensitivity and by extrapolation from controlled exposure studies of seals to small airguns we might expect seals to be at least as sensitive to pile driving as porpoises
Several studies have measured changes in numbers at adjacent haul outs
e.g. Skeat et al., 2012
Harbour Seals Hauled out at Scroby Sands
Grey Seals Hauled Out Scroby Sands
Operation Phase: Porpoises
 Turbine operational noise lower intensity predominantly at lower frequencies
 Less cause for concern
 Some POD studies suggest that porpoise populations return to pre‐construction levels after piling
 Not all have show this  This is a topic for which the OWEZ project has some interesting (perhaps surprising) new insights
Operation Seals
Operation Phase Seal Telemetry Study
McConnell et al 2012
Fine scale telemetry for five grey and five harbour seals at Danish wind farms in the North Sea
• Analysis of individual seals tracks
• Found no differences in‐
• residence times, • speed, • tortuosity of tracks • proximity to towers Significance
 Its clear that dramatic changes can occur during construction and affect very large numbers of animals
 Credible risk that hearing of smaller numbers of animals could be damaged
 Raises new questions
 How will these effects scale with larger developments and multiple constructions affecting the same animals over many years?
 Does this “really matter”?
 What is the biological significance for individuals or populations?
SOUND
Frequency
Level
Duration
Duty Cycle
Propagation
BEHAVIOUR
CHANGE
Movement
Vocalisation
Diving
Foraging
2
++
+
How Easy to Acquire
E
nd
a
se
au
r C
fe
In
LIFE FUNCTION IMMEIDATELY AFFECTED
Feeding
Survival
Breeding
Nurturing
Response to
Predators
ct
ffe
Potential to Infer (Transfer function)
+
Several expert groups are working to
explore how far this approach can be taken for the best know species. ectly
+
Meas
ure D
ir
+++
1
3
0
VITAL
RATES
Stage
Survival
Maturation
Reproduction
+
4
+++
POPULATION
EFFECTS Growth Rate
Popln Structure
Transient dynamics
Sensitivity
Elasticity
Extinction prob
+
Broader Questions
 Should populations consequences be Society’s only legitimate concerns?
 Habitats Directive prohibits Significant Disturbance for example
 The balance between the potential harm from disturbance and the broader environmental and economic benefits of renewables power generation is clearly an important topic for debate and discussion
OW Egmond ann Zee
 Important new information for the two key species at the site ‐ fundamental
 Carried out pioneering studies, highlighting approaches to use on future developments
 Careful extrapolation and new studies will be needed as much larger constructions in deeper waters impact a greater diversity of mammals including more vulnerable species. THANK YOU