How relevant are the effects of wind farm noise on fish?
Dr Mathias H. Andersson
Prof. Peter Sigray
Department of Underwater Research
FOI - Swedish Defence Research Agency
Stockholm, Sweden
Overview
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Fish and sound
Underwater noise and impact on fish
Noise criteria for injury in fish
Wind farm construction and operational noise
Examples
Implications
Challenges
Wind farms as artificial reefs
Fish and sound
Sound travels 5 times faster in water than air - 1500 m/s
Sound consists of :
- pressure variations – air-filled cavities
- particle motion– hearing organ (otholits/lateral line)
Both co-exists simultaneously!
Particle motion
Pressure
Herring
Cod
Black goby
Plaice
Fish and sound
Specializations leads to higher sensitivity to sound
Two-spotted goby
Zebra fish
Pictures by Hans-Erik Karlsen
Swim bladder
Audiograms
Clupeids (e.g. herring) has a
special connection between
swim bladder and inner ear
Fish and sound
Fish produce and listens to sound for:
• mating and communication
• localization of food
• avoiding predators
• navigation
Hearing range in fish overlaps in frequency
with many anthropogenic sound sources
From Slabbekoorn et al. 2010
Impact of noise en fish
What noise level a fish will be subjected to is determined by
several factors such as:
1. Source level
Audibility
2. Dominant frequency
3. Water depth
Masking
4. Sediment
Behavioural/physical reaction
5. Sound propagation (temp, salinity)
6. Ambient noise
And how they will react is determined by
the biology of the fish
1. Hearing ability
2. Behaviour
3. Life history
After Richardson et al. (1995). Marine mammals and
noise. Academic Press, San Diego
Injury, Death
Interim Criteria - injury
Effects to hearing and auditory tissues do not follow the equal energy
hypothesis (equal amounts of sound energy will produce equal effects,
regardless of how the sound energy is distributed in time), it is imperative to
include criteria that address both peak SPL and cumulative SEL. (Carlsson et al. 2007)
Interim Criteria for onset of injury in fish from piling noise (Popper et al. 2006)
• Peak sound pressure level (SPL): 208 dB re 1 µPa (peak)
• Sound exposure level (SEL): 187 db re 1 µPa2•sec
Update from US 2009: the onset of physical injury (inkl TTS) would be expected
if either the peak SPL exceeds 206 dB (re 1 μPa(peak)) or the SEL, accumulated
over all pile strikes generally occurring within a single day, exceeds 187 dB (re 1
μPa2•sec) for fishes 2 grams or larger, or 183 dB for smaller fishes. (Stadler and
Woodbury 2009)
There is no criteria in Europe for injury or for behavioural reactions!
Germany?
NOAA Fisheries uses a precautionary approach for assessing,
and minimizing, the potential effects on fish
Construction noise
Example “Pile driving”
Short duration, sharp and high in amplitude
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a lot of energy in a short time that is repeated
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noise should be described in Peak Sound
Pressure Level and Sound Exposure Level (SEL)
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measured source levels up to about 228 dB re 1
µPa(peak) for an individual strike (TNO 2009)
There is also in increase in ship traffic during the
construction of a wind farm but NO studies to
date has looked at this disturbance
Pile driving in the harbour of
Ålesund, Norway, 2011
Construction noise
Effect depends on:
Piling pulse change with distance
• peak pressure
• accumulation of energy over time
• the sharpness/rise time
• multiple exposures
• particle motion –in water/bottom
Impact
1. Barotrauma to swim bladder, tissues and hearing organs
even if the fish doesn't hear the sound (Caltrans 2001, 2004,
189 m
552 m
Halvorsen et al. 2011)
2. However, fish can regenerate hair cells (Smith et al. 2006)
3. Impact on behavior (Mueller-Blenkle et al. submitted), (Engås et al. 1996,
906 m
Wardle et al. 2001, Air-guns)
4. Possible masking of communication (No data yet!)
5. Effects on eggs and larvae (Not piling - Banner & Hyatt 1973,
Kostyuchenko 1973, Booman et al. 1996)
From Popper et al. 2006
The impact is highly species dependent !
Example of a behavioural reaction to re-played pile
drivning noise
Sole
Befor
During
After
Cod
Mueller-Blenkle et al. submitted
“Pile-driving sound affects the behaviour of marine fish”
Example of a behavioural reaction to replayed pile
drivning noise
There was a significant movement response to the pile-driving
stimulus in both species at received sound pressure levels of:
sole: 144 – 156 dB re 1μPa(peak); cod: 140 – 161 dB re 1μPa(peak);
Particle motion between 6.51x10-3 and 8.62x10-4 m/s2(peak)
These sound pressure levels could occur up to 70 km from a piling event
Particle motion – awaiting published measurements
Operational noise
Sound pressure dB re 1 µPa
A continuous broad band sound (1- 1000 Hz)with a few sharp
tones 100-200 Hz), Sound pressure SL 120-150 dB re 1 µPa(rms)
Noise from the gearbox propagated thru the tower and foundation into
the water – noise level depends on wind speed and foundation type.
127 Hz
Noise from one 2.4 MW turbine at Lillgrund
wind farm at different distances during 12m/s
Particle motion from a wind turbine in relation to fish
hearing
Wind turbine (1.45 MW)
noise not detectable for
particle motion sensitive
Species at a distance
of > 10 m
Sigray and Andersson 2011 Particle motion measured at an operational wind turbine in relation to
hearing sensitivity in fish, J. Acoust. Soc. Am. 130 (1), 200-207
500 turbines
80 turbines
Sound pressure dB re 1 µPa
Plans for two new farm in Hanöbukten in southern
Baltic Sea, Sweden – cumulative effects!
Ambient
Source level 136 dB re 1μPa for a 150 Hz tone
Large Wind Parks requires long-range wave-propagation as well as
influence of sound velocity profile
Cumulative effects has to be estimated
What does this mean?
What are the implications of being in a noisy environment?
Does it care?
Has it become habituated?
Will it stay even though it is disturbed?
Yes, it will stay if the area is important enough for:
‐ spawning, nursery, food
‐ or if it does not have enough energy to move
Habituation (decreased response to repeated stimuli) or sensitisation (increased response to repeated stimuli) to the noise could occur and are a temporal change in an animal’s individual tolerance
Indirect effects!
Few studies exist on physiological effect of noise on fish in a natural environment, however, laboratory studies shows:
Fish living in a noisy environment has increased levels of the stress hormone cortisol which could lead to:
‐> increased heart rate
‐> less growth, including adults, juveniles and larvae
‐> affected reproduction
Lessons learned from mice, rats, birds and humans (Kight & Swaddle 2011)
Possible masking of biological signals – only within the wind farm area
You have to be carful when extrapolating lab results to the sea – different acoustic environment
Good Environmental status (GES)
How does this correlate to the new EU Marine
Directive about the oceans Good Environmental
Status (GES), descriptor 11!
Mitigation
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Careful assessment of effects (SWE - Skottarevet)
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New technique introduced
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Deterrents
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Ramping up
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Reducing noise (i.e. bubble curtain, coffer dams)
New turbine without gearbox
This has to be done parallel to other activities
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Silencing ships
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Regulating underwater activities (EU Marine Directive)
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Moving shipping lanes
Nature 2000 Marine Silent Areas?
Challenges
1.
Perform field measurements of the ambient sound in the oceans over time and of various human activities – EU Marine Directive– both sound pressure and particle motion simultaneously
2.
Investigate any cumulative effect from multiple sound sources, i.e. large wind farms and/or ships within an area
3.
Does behavioural reactions have any impact on survival?
4.
Field studies on effects of noise on spawning, mate choice and growth 5.
What effect has masking on the acoustic communication – what are the implications?
From Slabbekoorn et al. 2010
Challenges
1.
Perform field measurements of the ambient sound in the oceans over time and of various human activities – EU Marine Directive– both sound pressure and particle motion simultaneously
2.
Investigate any cumulative effect from multiple sound sources, i.e. large wind farms and/or ships within an area
3.
Does behavioural reactions have any impact on survival?
4.
This has to be done interdisciplinary!
Field studies on effects of noise on spawning, mate Biologist and acousticians together!
choice and growth 5.
What effect has masking on the acoustic communication – what are the implications?
From Slabbekoorn et al. 2010
Wind turbine foundation as Artificial reef
Fish may appear within hours after the construction has been installed – attracted by the structure itself When a fouling assemblage has been developed, fish may be attracted to that habitat
→ Benthic species ‐ high food availability and protection from predators
→ Free ranging pelagic species aggregated due high abundance of prey
FAD
Black goby Two‐spotted goby
Wind turbine foundation as Artificial reef
Lillgrund wind farm (Sweden) 48 2.4 MW turbines on concrete foundation
Fish ecosystem studied 2002-2005, 2008-2010 using gillnet, fyke nets,
telemetry(Bergstöm et al. manuscript)
Summary of results
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No increase in fish number, biomass or fish species in the wind farm
area
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Aggregation of fish towards foundations <160 m (eel, viviparous
eelpout, cod, goldsinny wrasse, shorthorn sculpin and “shore crab”)
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Lower presences of eel and eelpout when wind farm where noisy
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Some migrating eel individuals avoided the wind farm area
Wind turbine foundation as Artificial reef
Overview of fish community structure within the wind farm and two control areas
Wind turbine foundation as Artificial reef
Egmond aan Zee (Holland) 36 3 MW turbines on steel monopile foundation
Fish studied using telemetry and gillnets 2007-2008 (Winter et al. 2012)
Summary of results
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Tagged sole showed no preference for the wind farm area
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Sole use a larger spatial scale than the wind farm
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Cod showed large variation in individual behaviour
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Only small (<50 cm) cod where found within the wind farm
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Part of the population stayed a long time (8-9 month) within the wind farm
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No difference in movement when the turbines was in operation or not (i.e.
noise disturbance)
Challenges in monitoring
To show that a wind farm has an effect on the fish population in a larger
area, positive, negative or no effect is quite difficult and requires several
years of monitoring to distinguish the effect of the wind farm from annual
variations.
It takes several years for many species to become sexually mature and
reproduce (e.g. for cod 2-4 years and for herring 3-5 years) and thus,
contribute to the population in terms of new individuals.
Commercial species like cod, eel, salmon, herring and several species of
flatfish are subjected to intense fishing making it even more difficult to
determine if any change in density was caused by the wind farm.
The common methods used in monitoring effects of wind farms, e.g.
echo sounders, otter and beam trawls, gillnet and fyke nets sample‘s only
parts of the fish ecosystem and will only alert for a drastic change in
fish community and miss small scale changes and species.
Very few studies published din peer- reviewed journals!
Thank you for your time!
Questions?
Dr Mathias H. Andersson
[email protected]
Prof. Peter Sigray
[email protected]
Department of Underwater Research
FOI - Swedish Defence Research
Agency
Example of a behavioural reaction to replayed pile
drivning noise
There was a significant movement response to the pile-driving
stimulus in both species at received sound pressure levels of:
sole: 144 – 156 dB re 1μPa(peak); cod: 140 – 161 dB re 1μPa(peak);
Particle motion between 6.51x10-3 and 8.62x10-4 m/s2(peak)
These sound pressure levels could occur up to 70 km from a piling event
Particle motion – awaiting published measurements
VRAP
Plattform
VRAP
VRAP
Sea surface
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Sandbed
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