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ABSTRACT
Regulators, funding agencies and proponents
worldwide are imposing increasingly strict
environmental regulations to minimise the
potential impact of marine construction
activities, and more specifically, the
underwater sound generated by such
activities. Marine fauna may be adversely
affected by marine construction as a result of
physical interaction with construction
equipment and/or exposure to high levels of
underwater sound. Physical interaction can
cause injury or death, exposure to high sound
levels may cause physiological effects (e.g.,
permanent or temporary hearing threshold
shifts), behavioural effects or masking.
To minimise the potential impact of marine
construction projects on marine fauna
worldwide Van Oord and SEAMARCO have
developed the FaunaGuard, an Acoustic
Deterrent Device, to safely and temporarily
deter various marine fauna species from
marine construction sites with specialised
underwater acoustics. The underwater
acoustics that are implemented in the
FaunaGuard have been designed and tested
scientifically for specific marine fauna species,
or species groups. A variety of signals is
already available or under development, i.e.,
for various species of marine fish, mammals
and reptiles. A number of practical
applications are described. The FaunaGuard is
a successful member of a broader family of
environmental Guards (FaunaGuard,
PlumeGuard, ReefGuard).
INTRODUCTION
Regulators, funding agencies and proponents
worldwide are imposing increasingly strict
environmental regulations to minimise the
potential impact of marine construction
activities, and the sound generated under water
by such activities.
Marine fauna may be adversely affected by
marine construction works as a result of physical
interaction with construction equipment and/or
exposure to high levels of underwater sound.
Physical interaction can cause injury or death,
exposure to high sound levels may cause
masking, physiological effects (e.g., temporary
or permanent hearing threshold shifts),
behavioural effects or masking.
Legislation for underwater sound, as it
emerges internationally (e.g., following the EU
Marine Framework Directive), increasingly
takes an ecosystem-based approach aiming to
keep sound levels in a sensitive habitat within
acceptable levels. The philosophy is not to
scare animals away from their known foraging
and breeding grounds, but to allow human
activities in that habitat only when impact
remains below maximum acceptable levels.
This triggers mitigating measures, such as air
bubble screens, that focus on reducing the
propagation of sound energy from the source.
When dealing with temporary high energetic
activities producing high peak levels of
underwater sound, sound suppressing
mitigation measures might no longer be
effective at acceptable cost. In order to
protect marine fauna from Temporary
Threshold Shift (TTS) and Permanent
Threshold Shift (PTS), Acoustic Deterrent
Devices (ADDs or pingers) still remain a viable
option in order to temporarily deter the
animals away to a distance where underwater
sound levels have dropped to safe values.
Many ADDs and pingers are commercially
available. An issue around such devices
remains that their effectiveness is often not
scientifically validated. As an alternative to
existing approaches Van Oord and
FAUNAGUARD: A SCIENTIFIC METHOD FOR
DETERRING MARINE FAUNA
H. VAN DER MEIJ, R. KASTELEIN, E. VAN EEKELEN AND M. VAN KONINGSVELD
Above: Schools of fish are typically encountered at
marine construction sites. FaunaGuard, an Acoustic
Deterrent Device, can safely and temporarily deter
various marine fauna species from these sites using
specialised underwater acoustics.
Faunaguard: A Scientific Method for Deterring Marine Fauna 17
SEAMARCO have developed the FaunaGuard,
an Acoustic Deterrent Device to safely and
temporarily deter various marine fauna species
from marine construction sites with specialised
underwater acoustics.
The underwater acoustics that are
implemented in the FaunaGuard have been
designed and tested scientifically for specific
marine fauna species or groups of species. A
variety of signals is already available or under
development for modular application to
various species of marine fish, mammals and
reptiles. The most recent module added to the
FaunaGuard (2014) has been designed for the
harbour porpoise (Phocoena phocoena).
This article describes important aspects of
marine fauna and (anthropogenic) underwater
sound, the philosophy behind the
FaunaGuard, its infrastructure and signal
library and its application scope.
MARINE FAUNA AND UNDERWATER
SOUND
Sound can be described as a moving wave in
which particles of the medium are forced
together and then move apart. This creates
changes in pressure that propagate with the
speed of sound. The speed of sound in water
is more than four times higher than the speed
of sound in air because the medium ‘water’
supports the propagation of sound better
than the medium ‘air’. In water, the
attenuation is less than in air.
Sound is produced under water by natural
and anthropogenic sources. Natural sources of
sound can be vocalisations of marine life, e.g.,
the elaborate songs of humpback whales or
the snapping of shrimp. Wind, rain, waves,
and subsea volcanic and seismic activity all
contribute to ambient sounds in bodies of
water. Anthropogenic sound comes from
construction of marine infrastructure
(including dredging) and industrial activities
such as drilling or aggregate extraction,
shipping, military activities using various types
of sonar, geophysical exploration using seismic
surveys, and a variety of other activities.
As sound propagates very well under water,
many marine species use it for a variety of
purposes. Both fish and marine mammals
communicate with underwater sound. Some
whales even communicate over distances as
large as hundreds of kilometres. Marine fauna
also uses sound for navigation, finding prey
and detecting predators.
HAZARDS OF ANTHROPOGENIC
SOUNDS
Anthropogenic sound interferences can have a
variety of effects on aquatic life (see Figure 1).
Once sounds of anthropogenic origin are loud
enough to be in the audible range of marine
fauna, they may first mask biologically
important signals such as communication calls
between animals. When sound levels increase,
the severity of the response also increases
ranging from subtle, such as a startle
response, to strong behavioural reactions,
such as complete avoidance of an area. When
sound levels received by marine fauna are
even higher, they can affect hearing either
temporarily or permanently and extremes can
lead to injury or even death. The latter,
however, occurs only when animals are very
close to a very high intensity sound source.
Like many other activities, dredging and
marine construction activities produce
underwater sound. The Central Dredging
Association (CEDA) has published a position
paper on this topic and encourages the
development of a standardised monitoring
protocol for underwater sound, to facilitate
evaluations of reasonable and appropriate
management practices to reduced underwater
sound production during dredging (CEDA,
2011).
FAUNAGUARD PHILOSOPHY
The philosophy of the FaunaGuard, developed
by Van Oord and SEAMARCO, is to make
optimal use of the behavioural effects induced
by specific sounds with different species or
species groups. By deliberately making an area
in and around a dredging or marine
construction site (temporarily) unattractive to
marine fauna, more serious effects related to
high peak energy events may be prevented.
As such the FaunaGuard aims to utilise mild
behavioural effects (moving from an area) just
before construction, to prevent more serious
physiological effects on marine fauna during
construction.
The careful use of underwater sound has
some additional advantages. Traditional
mitigating measures rely on visual
observations, e.g., by Marine Fauna Observers
(MFOs), or physical contact, such as turtle
deflectors and physical relocation. Both
methods, though effectively used in practice,
have limitations:
Visual observations are less effective when
marine fauna are not at the water surface,
when turbidity levels are higher or visibility
is low in general (such as during bad
weather or at night).
18 Terra et Aqua | Number 138 | March 2015
Figure 1. Ranges of effects of
sounds on Marine Mammals
(Courtesy of SEAMARCO).
HEIDI VAN DER MEIJ
received a degree in Environmental
Technology and Ecological Conservation at
Saxion Universities of Applied Sciences,
Deventer, the Netherlands in 2000. She
then worked as a biological analyst in the
Oceanium of the Rotterdam Zoo. In 2007
she joined Van Oord’s (Environmental)
Engineering Department where she aims to
influence the project design towards eco-
friendly alternatives and encourage
environmental management, mitigation
and monitoring on projects.
RON KASTELEIN
received his PhD from the Agricultural
University of Wageningen, the Netherlands
in 1998 on ‘Food consumption and growth
of marine mammals’. In 2002 he founded
SEAMARCO B.V. (Sea Mammal Research
Company Inc.) which specialises in applied
acoustic research with marine fauna. He is
(co)author of many publications, in diverse
disciplines such as anatomy, physiology,
behaviour, acoustics, biomechanics,
sensory systems, animal medicine, animal
welfare and psychophysics.
ERIK VAN EEKELEN
graduated in 2007 as an MSc from Delft
University of Technology, the Netherlands,
on the subject of the environmental
impacts of dredging plumes from TSHDs.
He then joined Van Oord’s Environmental
Engineering Department, working on a
wide variety of environmental aspects of
their dredging and maritime construction
projects, such as Eco-Design, turbidity
management and protection of marine
fauna both in the Netherlands and abroad.
MARK VAN KONINGSVELD
received an MSc (1998) and subsequently
a PhD degree (2003) in Civil Engineering
from the University of Twente, Enschede,
the Netherlands. His PhD research,
executed at WL|Delft Hydraulics, later
Deltares, focussed on Matching Specialist
Knowledge with End User Needs. After
several years working at Deltares he joined
Van Oord (2008) where he is currently the
manager of the Environmental Engineering
Department. He aims to proactively provide
clients with state-of-the-art solutions.
Methods that rely on physical contact (like a
turtle deflector or re-location of species by
divers / nets) may still cause stress and
impact to the fauna.
Physical devices may adversely affect the
efficiency of dredging operations or even
cause safety issues.
A modern alternative mitigation technique is
to make use of Passive Acoustic Monitoring
(PAM) to acoustically detect the presence of
marine mammal species such as whales and
porpoises. The use of PAM systems alone is
often insufficient, as it is difficult to discern
between different species as well as to
establish the exact location of the detected
animal in relation to the position of the PAM.
Last but not least it is good to realise that
PAM systems can only work when animals
vocalise.
The FaunaGuard is an Acoustic Deterrent
Device (ADD), albeit one with customised
hardware specifications to allow for the
emission quite specific signals at the
appropriate levels of intensity. ADDs, as they
are available on the market, vary greatly in
source level, spectrum (and thus the effective
range), duty cycle, proven effectiveness and
durability. The most innovative aspect of the
FaunaGuard is the fact that it deters marine
fauna with species specific or group specific
(safe) acoustics that are tested scientifically for
their effectiveness. This means that the
acoustic signals that are emitted by the
FaunaGuard have been specifically selected
(frequency spectrum, loudness, temporal
structure, duty cycle) for specific species of
marine fauna. The tailor-made sounds enable
a more focussed deterring approach, which
minimises impacts on the target species, as
well as on other species, and improves the
likelihood for fauna to survive.
FAUNAGUARD HARDWARE
The FaunaGuard consists of sound-emitting
equipment and sound-receiving equipment (to
allow users to check that the device is
working). In principle each FaunaGuard
module is purpose-built for a target species,
although it is possible to combine several
modules into one device.
The FaunaGuard randomly emits sounds that
are all designed to fit specific requirements for
the target species. The different sounds are
based on the hearing range and sensitivity of
the species (frequency spectrum) and the
reaction threshold levels, based on known
literature and extensive behavioural response
experiments.
The frequency spectrum of the deterring
sounds of the FaunaGuard have been
designed to be within the functional hearing
range of the target animals, and within the
range of best hearing, so that the sensation
level (number of dB above the hearing
threshold for a particular frequency) is as high
Faunaguard: A Scientific Method for Deterring Marine Fauna 19
Figure 2. Sounds tested on sea turtles at Rotterdam Zoo (Courtesy of SEAMARCO).
20 Terra et Aqua | Number 138 | March 2015
as possible (thus creating a deterring range
that is as large as possible).
Furthermore, if possible, the signal duration
and frequency spectrum takes into account
the species directional hearing abilities, as to
assure that the species know where to move
away from (i.e., in which direction to go to
minimise the sound level).
For almost all animals, sounds with
complicated spectra have a greater deterring
effect than pure tones. Therefore, the
FaunaGuard emits a variety of complex
sounds such as sounds with harmonics,
sweeps, and impulsive sounds. In addition,
sounds have various durations and are
emitted with random inter-pulse intervals, to
reduce the habituation process.
The higher the level of the sounds emitted,
the greater the effective range of the
FaunaGuard. To allow sounds of high level to
be produced, a transducer is selected that
has:
a high output level in the desired frequency
range (i.e., in the hearing range of the
target species), and
omni-directionality for the higher
frequencies (for this purpose a ball
hydrophone is used, transmitting the
sounds in 3 dimensions).
The sound level emitted by the FaunaGuard
can be adjusted depending on the required
effective range. Additionally, for the safety of
the animal’s hearing the sound level is slowly
ramped up after the FaunaGuard is activated.
It takes 5-10 minutes to reach the maximum
output level. This gives marine fauna time to
swim away before maximum output of the
FaunaGuard is reached.
FAUNAGUARD TESTED SOUNDS
Since 2010, Van Oord has commissioned
SEAMARCO to test and compose the
FaunaGuard modules for different species of
marine fauna. The following behavioural
response experiments have been performed
under laboratory conditions at the
SEAMARCO facilities in Wilhelminadorp,
Rotterdam Zoo and the Arsenaal Aquarium in
Vlissingen, all located in the Netherlands.
Responses to sound and light stimuli
by Atlantic green turtles (Chelonia
mydas) and Hawksbill turtles
(Eretmochelys imbricata) in a pool at
Rotterdam Zoo, 2010
A study on the effects of sound and light
stimuli on the behaviour of Atlantic green
turtles (Chelonia mydas) and Hawksbill turtles
(Eretmochelys imbricata) was conducted in an
indoor pool at Rotterdam Zoo, the Netherlands
(see Figure 2). The pool was set up in the
quarantine area of the zoo’s aquarium
department which is not open to visitors and
therefore relatively quiet. The turtles were kept
in pairs in an oval pool (7.6 m (l) x 5 m (w) x
1 m (d)). Two 1-m-long male Atlantic green
turtles (Chelonia mydas) and two 1-m-long
Hawksbill turtles (Eretmochelys imbricata) were
subjects for this study.
The FaunaGuard experiment at Rotterdam
Zoo produced several signals that triggered a
clear behavioural response with the turtles in
the test facility. The experiment furthermore
produced a number of helpful lessons learnt
regarding the type of signals that were
effective, which aspects to take into account
when deterring turtles and the optimal signal
duration in order to elicit a behavioural
response.
Differences were observed in responses to
sound between individuals in the pool. Owing
to the small sample size, it cannot be
determined if these differences were
individual, age related, or species specific.
When the turtles were in a sleep phase, they
were very difficult to “wake up”. As a result,
the exposure level required to elicit
behavioural responses in turtles needs to be
high. However, above a certain level, it is the
spectrum which determines whether a turtle
responds to a sound. Responses were mainly
seen to sounds below 1 kHz. This is in
agreement with the literature about the
frequency range of hearing in turtles. Typical
Figure 4. Shark and fish
pilot study at
‘The Arsenaal’ in
Vlissingen, the Netherlands
(Courtesy of SEAMARCO).
Figure 3. Fish tests at SEAMARCO Institute in Zeeland (Courtesy of SEAMARCO).
performed in a public aquarium (Figure 4). If
the sharks would react to the emitted sounds,
a larger study was envisioned.
Four shark species, one stingray species, and
three bony marine fish species were exposed
to the sounds of the fish module of the
FaunaGuard (duration of sounds: 10 seconds,
once every 5 minutes). The sharks often
showed a change in swimming pattern after
exposure to the sounds (during and often
after signal presentation). The sharks reacted
relatively strongly to three signal types (square
waves, white noise and down-sweep) and
strongly to one signal type (down-sweep).
Also, t
he sharks reacted relatively strongly to
several of the high frequency down-sweeps.
Most of the shark species reacted to the high
frequency sounds with a slightly higher activity
level and a change in swimming pattern.
All bony fish species reacted to the
FaunaGuard sounds (Sea bass and Yellowtail
Kingfish reacted both equally strong to the
sounds, and they reacted stronger than Cod).
None of the bony fish species reacted to
sounds above 1 kHz. Whether the sharks
reacted to the FaunaGuard sounds directly, or
to the response of the bony fish to the
FaunaGuard sounds indirectly, could not be
established conclusively. However, sharks at
sea are likely to follow fish (their prey) that
behave abnormally (such as during flight), and
this response may lead them to follow the fish
and thus out or harm's way. When an
opportunity arises this aspect will be
investigated in greater detail.
Faunaguard: A Scientific Method for Deterring Marine Fauna 21
20 sounds on the fish in the facility could be
made. Ten of the 20 sounds were very
effective in causing behavioural responses in
the fish. These responses were classified
according to type and duration. The sounds
that caused little or no effect were outside the
most sensitive hearing range of most fish
species and outside the resonance frequency
range of the transducer (meaning that they
were produced at a lower source level). These
10 sounds produced by the FaunaGuard have
been replaced by other, more effective, sounds.
Responses of 4 shark species,
stingrays and 3 bony marine fish
species to underwater sounds
produced by the FaunaGuard, 2012
The effectiveness of the FaunaGuard on bony
fish (Teleosts; skeletons are made of bone)
has been shown qualitatively during several
field deployments at marine construction
projects in Sweden and Brazil in 2011 and
2012. The exact effectiveness was established
in studies under laboratory conditions in a
pool at SEAMARCO (2011) (see Figure 3).
Next, the effectiveness of the FaunaGuard Fish
Module on sharks (Elasmobranchs; skeletons
made of cartilage; sharks, rays and dogfish)
was studied.
Because sharks are more dependent on their
electro-magnetic and olfactory senses, the
likelihood of them reacting to sounds was
expected to be smaller than for bony fishes. A
pilot study on whether behavioural responses
from sharks could be elicited with sound was
behavioural responses were an increase in
activity and a change in swimming pattern.
Even though the experimental setup had
some limitations (relatively small basin size,
limited size test population), the overall results
are useful. Additional tests are planned to
further refine the signals found so far, apply
these under various field conditions and test
them on more sea turtle individuals.
Responses of captive North Sea fish
species to underwater sounds
produced by the FaunaGuard, 2011
The FaunaGuard Fish Module was designed to
produce (safe) sounds to deter fish from areas
where harmful sounds are about to be made.
Though qualitative evidence from deployment
on a dredging project in Sweden suggests
that the FaunaGuard effectively deters fish, no
scientific data on the behavioural responses of
fish to the sounds produced by the
FaunaGuard was available.
Therefore the behavioural responses of two
captive marine fish species to sounds
produced by the FaunaGuard were observed,
recorded and quantified (see Figure 3). The 20
sounds of the FaunaGuard Fish Module were
tested on five schools of sea bass
(Dicentrarchus labrax) falling into three size
classes and on three schools of thicklip mullet
(Chelon labrosus) of one size class.
Although the two fish species responded
slightly differently to the sounds, several
generalisations on the effectiveness of the
Figure 5. Harbour
porpoise behavioural
response study at
SEAMARCO Institute in
Zeeland, the Netherlands
(Courtesy of
SEAMARCO).
The effective distance was far enough to
prevent Permanent Hearing Threshold Shift
(PTS) in harbour porpoises caused by pile
driving sounds.
FAUNAGUARD PRACTICAL
APPLICATIONS
In order to deter marine fauna from its marine
construction sites, Van Oord has applied the
FaunaGuard in different projects worldwide.
Key to effective deployment is the careful
design of a management framework in which
a mitigating measure such as the FaunaGuard,
can be embedded. Garel et al. (2014) illustrate
the applicability of the Frame of Reference
(FoR) approach in the design of such
management frameworks for offshore
renewable energy projects.
The FoR approach was developed to help
researchers from various fields of expertise to
use one generically applicable method to
embed their results in a practical decision
context (Van Koningsveld et al., 2003; Van
Koningsveld and Mulder, 2004; Van
Koningsveld et al., 2005). The approach is
characterised by the coherent definition of
clear objectives at strategic and operational
(or tactical) levels and an operational phase
where indicators are defined to verify whether
or not these objectives are met. A simple
example that involves the deployment of a
FaunaGuard is discussed below (see Table I).
Let’s assume that a virtual offshore wind
energy project in Europe is considered, for
Behavioural response study of
porpoise on underwater sounds
produced by the FaunaGuard,
March – May 2014
To estimate the mean received behavioural
threshold level of harbour porpoises for the
sounds of the FaunaGuard Porpoise Module,
and establish an acoustic dose-behavioural
response relationship, a porpoise in a pool
was exposed to the sounds at seven mean
received Sound Pressure Levels (SPLs). Two
behavioural parameters were recorded during
control and test sessions: the number of
respirations (stress indicator) and the animal’s
distance to the transducer. The experimental
setup that was used to test this is shown in
Figure 5.
The number of respirations differed
significantly between control and test sessions
at mean received test levels of 104 dB re 1µPa
and above. The porpoise’s distance to the
transducer was significantly greater during
test sessions than during control sessions
when mean received levels in test sessions
were 86 dB re 1µPa and above. The results
show that harbour porpoise will respond to
the FaunaGuard by swimming away from it.
The FaunaGuard Porpoise Module is effective
at deterring harbour porpoises, in part owing
to the high frequency sounds it produces. This
allows the porpoise to localise the sound
source more easily. To calculate the deterring
distance or effective range of the FaunaGuard
for harbour porpoises at sea, information on
the Source Level, the behavioural threshold
level for distance established in the present
study, and modelled information on the local
propagation conditions and ambient noise
need to be combined. For a specific
construction site in the North Sea (Eneco
Luchterduinen wind turbine park), TNO has
calculated the effective distance (~1.3 km).
22 Terra et Aqua | Number 138 | March 2015
Figure 6. FaunaGuard in
Norrköping (Sweden)
hanging off the drilling and
blasting barge before
deployment.
Table I. Example of Frame of Reference (FoR) approach on one effect (impact on mammals) of wind energy projects.
Environmental
issue
Strategic
objective
Tactical
objective
Quantitative
State concept
Benchmarking
desired state
Benchmarking
current state
Intervention
procedure
Evaluation
procedure
Harbour
porpoise
protection
To preserve
the regional
harbour
porpoise
population
given the
planned
construction
activity
To prevent
individual
porpoise being
present in the
area with high
risk for
Permanent
Hearing
Threshold Shift
(PTS)
Number of
individuals
within 1000 m
from source
15 min. prior to
start of piling
activities
No individuals in
1000 m radius
15 min. prior to
start of piling
activities
Observed
number of
individuals in
1000 m radius
15 min. prior to
start of piling.
If observed
number of
individuals
exceeds the
benchmark,
activate the
FaunaGuard.
Observations
may be a
combination of
MMOs and
PAMs
If intervention
procedure does
not achieve the
benchmark
adapt the setup
(change signal,
adjust loudness,
increase number
of devices).
Faunaguard: A Scientific Method for Deterring Marine Fauna 23
modelling). Based on the above described
research and practical experience, the
FaunaGuard (porpoise module) has been
accepted by the regulatory agency of the
Dutch government and has been employed
during the construction of the Eneco
Luchterduinen Wind Farm.
which the Environmental Impact Assessment
(EIA) has reported the following
environmental concern: “Mammals: Harbour
porpoises (Phocoena phocoena) are abundant
in the area and may suffer hearing injuries
and death as a result of the emission of
underwater sound from devices and vessel.”
One might select “to preserve the regional
harbour porpoise population given the
planned construction activity” as the strategic
objective for the management framework for
Mammals. As a subsequent tactical objective
one might choose “to prevent individual
porpoise being present in the area with high
risk for Permanent Hearing Threshold Shift”.
Let’s say that research for the EIA has shown
that the zone with Permanent Hearing
Threshold Shift (PTS) risk is a circle with a
radius of 1000 m around the sound source. A
common first step would then be, to assess
the number of individuals that are present in
the area and compare that number with the
benchmark value. For this either Marine Fauna
Observers (MFOs) or Passive Acoustic
Monitoring (PAM) or a combination of these
two may be utilised. A management measure
could be that piling should not start as long
as there are still porpoise present in the area.
Properly implemented this framework should
prevent any harbour porpoise suffering PTS.
However, as discussed above under
“Faunaguard philosophy”, MFOs and PAMs
alone are not always sufficient. An additional
management measure could be to activate
the FaunaGuard and make the area of
potential risk temporarily unattractive to
porpoise.
As the FaunaGuard provides an evidence
based approach, theoretically other measures
could be omitted. It is good practice,
however, to establish at the start of each
project that the anticipated effectiveness and
effective range are indeed achieved. Once this
is confirmed other monitoring efforts may be
reduced. The reasoning described in the
above example has been applied to several
practical applications. First field application of
the FaunaGuard was in Norrköping, Sweden
(Figure 6), where drilling, but mainly the
blasting, activities were possibly a hazard to
the fish and a threat to the fishing industry
within the fjord. By introducing low frequency
specialised sounds from the FaunaGuard (fish
module), the impact on fish in the blasting
area was minimised. Owing to minimal
preparation time, SEAMARCO had included
sounds in the fish module of the FaunaGuard
that were chosen based on literature study
and experience. During the project the
effectiveness of the FaunaGuard was
confirmed with observations made on site.
After the project finished the FaunaGuard was
shipped to the SEAMARCO facilities for
service and for further testing of the fish
module.
After the field application in Sweden and the
lab tests for the fish module, drilling and
blasting operations in a more tropical region,
Brazil (Figure 7), called for an addition in
species representation: the dolphin module
was added to the FaunaGuard. Because of the
limited information about the responses of
dolphins (toothed whales) to sounds, the
sounds produced by the dolphin module are
based on studies with harbour porpoises.
Many studies have been conducted on this
species in relation to the development of
pingers to deter the porpoises from gill nets
(Kastelein et al., 1995-2014). In Brazil, the
FaunaGuard has been applied for drilling and
blasting operations on two projects in
different regions. The successful application
was confirmed on site and even reported in a
technical certificate from the Brazilian Institute
of the Environment and Renewable Natural
Resources (IBAMA) stating that “… the use of
a probe for scaring off fish and dolphins, is
worthy of note, for it has proved to be very
efficient in scaring fish before detonations”.
The latest research and successful application
for harbour porpoises has been performed
during the construction phase of the Eneco
Luchterduinen Wind Farm (a partnership
between Eneco and the Mitsubishi
Corporation) in the Dutch North Sea (Figure
8). In this case the FaunaGuard has been used
as a mitigation measure to deter harbour
porpoises sufficiently far away (about 1 km)
from piling activities to prevent permanent
hearing threshold shift (PTS).
For this measure to be acceptable to the
regulator, its effectiveness had to be validated
by means of behavioural response study. The
effective range of the FaunaGuard should be
larger than the distance at which piling can
cause PTS (based on sound propagation
Figure 8. Installation vessel Aeolus at work during the
construction phase of the Eneco Luchterduinen Wind
Farm in the Dutch North Sea.
Figure 7. FaunaGuard transducers and hydrophone in
São Francisco do Sul, Brazil.
24 Terra et Aqua | Number 138 | March 2015
REFERENCES
CEDA Position Paper - 7 November 2011:
Underwater Sound, In relation to Dredging,
CEDA Working Group on Underwater Sound,
www.dredging.org.
Garel, E., Camba Rey, C., Ferreira, O. and van
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2.0.CO;2.
CONCLUSIONS
The FaunaGuard is an Acoustic Deterrent
Device (ADD), albeit one with customised
hardware specifications to allow for the
emission quite specific signals at the
appropriate levels of intensity. It makes
optimal use of the scientifically confirmed
behavioural effects induced by specific
sounds with different species or species
groups.
By deliberately making an area in and
around a dredging or marine construction
site (temporarily) unattractive to marine
fauna, more serious effects related to high
peak energy events may be prevented. As
such the FaunaGuard utilises mild
behavioural effects (moving from an area)
just before construction, to prevent more
serious physiological effects on marine
fauna during construction.
As the FaunaGuard provides an evidence
based approach, additional monitoring and
mitigating measures may be reduced after
the predicted effectiveness and effective
range have been confirmed for a specific
project site. Several field applications have
been described to illustrate the approach.
Van Oord will continue to further develop
the FaunaGuard (hardware as well as
signal library) in collaboration with
SEAMARCO and other marine fauna
specialists worldwide. Additional laboratory
studies are foreseen to improve and extend
the signal library.
Further field verification tests are foreseen
to better understand how site conditions
influence the FaunaGuard’s effectiveness.
The rugged ness of the equipment, a
requirement for offshore conditions, will
be improved. Practical applications will be
used to improve the environmental
management framework in which the
FaunaGuard is used.
... The different sounds are based on the hearing range and sensitivity of this species (frequency spectrum) and the reaction threshold levels, based on known literature and extensive behavioural response experiments. The frequency spectrum of the deterring sounds of the FaunaGuard have been designed to be within the functional hearing range of the target animals, and within the range of best hearing, so that the sensation level (number of dB above the hearing threshold for a particular frequency) is as high as possible, thus creating a deterring range that is as large as possible (VAN DER MEIJ et al. 2015). ...
... One difference between Gemini and the other investigated OWFs was the usage of the seal scarer at the latter, whereas at Gemini a FaunaGuard was used. The FaunaGuard is especially designed to disturb porpoises but it is operated at lower noise levels (VAN DER MEIJ et al. 2015). GEELHOED et al. (2018a) found no negative effects of the FaunaGuard on the acoustic activity of harbour porpoises at Gemini. ...
... One difference between Gemini and the other investigated OWFs was the usage of the seal scarer at the latter, whereas at Gemini a FaunaGuard was used. The FaunaGuard is especially designed to disturb porpoises, but it is operated at lower noise levels ( VAN DER MEIJ et al. 2015). GEELHOED et al. (2018a) found no negative effects of the FaunaGuard on the acoustic activity of harbour porpoises at Gemini. ...
... The duration of ADD mitigation must be sufficient to allow animals time to flee from the near-field but be minimized to avoid unnecessary far-field behavioural disturbance. Given the strong observed response to the Lofitech ADD used in this development, we recommend further evaluation of alternative ADD systems such as FaunaGuard (Van der Meij, Kastelein, Van Eekelen, & Van Koningsveld, 2015), which offer the potential to minimize both near-field injury risks and avoid broader-scale behavioural displacement. Another critical consideration is any requirements for re-deployment of ADDs following planned or unplanned breaks in piling. ...
Article
Full-text available
1. Offshore windfarms require construction procedures that minimize impacts on protected marine mammals. Uncertainty over the efficacy of existing guidelines for mitigating near-field injury when pile-driving recently resulted in the development of alternative measures, which integrated the routine deployment of acoustic deterrent devices (ADD) into engineering installation procedures without prior monitoring by marine mammal observers. 2. We conducted research around the installation of jacket foundations at the UK's first deep-water offshore windfarm to address data gaps identified by regulators when consenting this new approach. Specifically, we aimed to (a) measure the relationship between noise levels and hammer energy to inform assessments of near-field injury zones and (b) assess the efficacy of ADDs to disperse harbour porpoises from these zones. 3. Distance from piling vessel had the biggest influence on received noise levels but, unexpectedly, received levels at any given distance were highest at low hammer energies. Modelling highlighted that this was because noise from pin pile installations was dominated by the strong negative relationship with pile penetration depth with only a weak positive relationship with hammer energy. 4. Acoustic detections of porpoises along a gradient of ADD exposure decreased in the 3-h following a 15-min ADD playback, with a 50% probability of response within 21.7 km. The minimum time to the first porpoise detection after playbacks was > 2 h for sites within 1 km of the playback. 5. Our data suggest that the current regulatory focus on maximum hammer energies needs review, and future assessments of noise exposure should also consider foundation type. Despite higher piling noise levels than predicted, responses to ADD play-back suggest mitigation was sufficiently conservative. Conversely, strong responses of porpoises to ADDs resulted in far-field disturbance beyond that required to mitigate injury. We recommend that risks to marine mammals can be further minimized by (1) optimizing ADD source signals and/or deployment schedules to minimize broad-scale This is an open access article under the terms of the Creative Commons Attribution License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited.
... Four different modules have been developed, tailor made to deter either porpoises, seals, fish or turtles. The development of the FaunaGuard is based on behavioural response studies both ex situ and in situ for these different fauna groups (Van der Meij et al., 2015). ...
Technical Report
Full-text available
The so-called FaunaGuard-PM (FG-PM) has been developed to deter harbour porpoises from localised offshore anthropogenic activities in order to minimize potential negative effects of these activities on porpoise hearing. The efficiency of the FG-PM was tested in a pool and the distance up to which it would deter porpoises in the field has been modelled, but was not tested at sea. The aim of this study was to test and evaluate the efficiency of the FG-PM to deter porpoises under field conditions. Porpoise behaviour was studied by simultaneous visual observations and passive acoustic monitoring in the vicinity of a periodically active FG-PM in the Marsdiep, Western Dutch Wadden Sea, in February-April 2016. Visual observations and passive acoustic monitoring took place during a series of pre-exposure (at least 1 h FG-PM off), exposure (15 min FG-PM on) and post-exposure experiments (up to 2 hrs FG-PM off). Visual observations and continuous video recordings were made from a vantage point on the southern tip of Texel. CPODs were stationed at different distances from the FG-PM to record unseen underwater activity of harbour porpoises acoustically. The visual observations showed that the FG-PM deterred harbour porpoises up to distances of at least 1000 meters. Most of the acoustic monitoring data during FG-PM exposure experiments corroborated the expected results, but due to equipment failure most of these data were of limited value. During post-exposure, shortly after the FG-PM was turned off, harbour porpoises were detected again in the vicinity of the FG-PM. This study confirms that the FG-PM is successful in deterring harbour porpoises up to at least 1000 m in the field conditions studied, and that porpoises were seen in the exposed area shortly after the FG-PM was deactivated.
... Another potential strategy for minimizing interactions of marine turtles with anthropogenic activities, including dredging, is to warn or repel marine turtles from areas where potentially harmful activities are or will take place. Given that marine turtles can detect and respond to low-frequency acoustic stimuli, acoustic harassment devices (AHDs) and acoustic deterrent devices (ADDs) could be used as a strategy to successfully repel marine turtles from various threats, including from areas that are being dredged or potentially high interaction fishing areas (Van Der Meij et al., 2015). The ROTAG could be used to test and determine the effectiveness of various ADDs or AHDs providing insights into further development of these devices and their suitability as mitigation strategies to protect marine turtles. ...
Article
Full-text available
Increases in the spatial scale and intensity of activities that produce marine anthropogenic sound highlight the importance of understanding the impacts and effects of sound on threatened species such as marine turtles. Marine turtles detect and behaviorally respond to low-frequency sounds, however few studies have directly examined their behavioral responses to specific types or intensities of anthropogenic or natural sounds. Recent advances in the development of bio-logging tools, which combine acoustic and fine-scale movement measurements, have allowed for evaluations of animal responses to sound. Here, we describe these tools and present a case study demonstrating the potential application of a newly developed technology (ROTAG, Loggerhead Instruments, Inc.) to examine behavioral responses of freely swimming marine turtles to sound. The ROTAG incorporates a three-axis accelerometer, gyroscope, and magnetometer to record the turtle’s pitch, roll, and heading; a pressure sensor to record turtle depth; a hydrophone to record the turtle’s received underwater acoustic sound field; a temperature gauge; and two VHF radio telemetry transmitters and antennas for tag and turtle tracking. Tags can be programmed to automatically release via a timed corrodible link several hours or days after deployment. We describe an example of the data collected with these tags and present a case study of a successful ROTAG deployment on a juvenile green turtle (Chelonia mydas) in the Paranaguá Estuary Complex, Brazil. The tag was deployed for 221 min, during which several vessels passed closely (<2 km) by the turtle. The concurrent movement and acoustic data collected by the ROTAG were examined during these times to determine if the turtle responded to these anthropogenic sound sources. While fine-scale behavioral responses were not apparent (second-by-second), the turtle did appear to perform dives during which it remained still on or near the sea floor during several of the vessel passes. This case study provides proof of concept that ROTAGs can successfully be applied to free-ranging marine turtles to examine their behavioral response to sound. Finally, we discuss the broad applications that these tools have to study the fine-scale behaviors of marine turtles and highlight their use to aid in marine turtle conservation and management.
... The effectivity of the FaunaGuard is (ID numbers 01 and 02). They were both 10 y old being studied both in pools and at sea for porpoises, during the study, and the body weight of each was fish, turtles, and seals ( Van der Meij et al., 2015). ...
Article
Full-text available
To prevent permanent hearing impairment in seals, SEAMARCO and Van Oord Dredging and Marine Contractors have developed the FaunaGuard Seal Module (FG-SM), which is intended to deter seals to safe distances from high-amplitude impulsive sound sources such as offshore pile driving operations. As a first step towards testing and validating the FG-SM, a study with captive harbor seals is presented. The effects of 16 sounds (200 Hz to 20 kHz, with random inter-sound intervals of 3 to 10 s, mean interval 6.5 s, and duty cycle ~60%) produced by the FG-SM on the behavior of two harbor seals were quantified in a pool. The overall behavioral response threshold for these sounds was determined by transmitting the sounds at four sound pressure levels (SPLs) at two background noise levels resembling those occurring during Beaufort Sea States 0 and 4. Behavioral responses ranged from no reaction to increased time spent with the head above the water surface, more frequent hauling out, and increased numbers of jumps. The seals differed in their responses to the sounds: whereas seal 01 increased the time she spent with her head above the water surface as the SPL increased, seal 02 hauled out more often. Based on "jump" behaviors specifically, the mean received behavioral threshold SPL of the two seals in both background noise conditions appeared to be between 136 and 148 dB re 1 pPa (for the effect calculation, 142 dB re 1 p,Pa was used). No effect of the ambient noise level was observed; the level of the ambient noise at both Sea States was too low to mask the sounds of the FG-SM at the average levels the animals were exposed to in the pool. Based on the source level of the FG-SM, the mean behavioral response threshold SPL found in the present study for jumps, and two generic propagation models, the deterring effect range of the FG-Sm is estimated to vary between 100 m (propagation model: 20log R) and 500 m (propagation model: 15log R). In most cases in the shallow North Sea, permanent hearing threshold shift (PTS) in harbor seals would be prevented if they moved 100 to 200 m away from the source of pile driving sounds, and, thus, the FG-SM is considered a good mitigation device. ADD (Acoustic Deterrent Device)*AHD (Acoustic Harassment Device)*and AMD (Acoustic Mitigation Device).
Article
Full-text available
To compare the effect of naval sonar up-sweeps and down-sweeps on the behavior of harbor porpoises, a harbor porpoise in a large pool was exposed to simulated low- and mid-frequency active sonar signals (series of 1-s duration frequency-mod-ulated sweeps). Three sweep pairs were tested: (1) a 1 to 2 kHz up-sweep was compared with a 2 to 1 kHz down-sweep (both without harmonics) at a mean received sound pressure level (mean received SPL) of 114 dB re 1 μPa; (2) a 1 to 2 kHz up-sweep was compared with a 2 to 1 kHz down-sweep (both with harmonics; mean received SPL: 123 dB re 1 μPa); and (3) a 6 to 7 kHz up-sweep was compared with a 7 to 6 kHz down-sweep (both without harmonics; mean SPL: 107 dB re 1 μPa). For each sweep pair, the level was chosen during a pretest session with the intention that the harbor porpoise would respond to the sounds by moving away from the projector and surfacing more often (i.e., he would show a change in behavior). The study consists of three separate parts, so only a comparison within sweep pairs could be made and not between sweep pairs. For the 1 to 2 kHz sweeps with harmonics, the harbor por-poise swam further away from the sound source in response to the up-sweeps than to the down-sweeps. For the other two sweep pairs, sweep type (up-sweep or down-sweep) caused no significant difference in the harbor porpoise's response. Thus, to allow the evaluation of potential effects of sonar sounds on harbor porpoises, sonar signal measure-ments should include the harmonics. For simulated naval sonar sounds with fundamental frequencies in the 1 to 2 kHz range containing harmonics, using down-sweeps appears to affect harbor por-poise behavior less than using up-sweeps.
Article
Full-text available
The high under-water sound pressure levels (SPLs) produced during pile driving to build offshore wind turbines may affect harbor porpoises. To estimate the discomfort threshold of pile driving sounds, a porpoise in a quiet pool was exposed to playbacks (46 strikes/min) at five SPLs (6 dB steps: 130-154 dB re 1 μPa). The spectrum of the impulsive sound resembled the spectrum of pile driving sound at tens of kilometers from the pile driving location in shallow water such as that found in the North Sea. The animal's behavior during test and baseline periods was compared. At and above a received broadband SPL of 136 dB re 1 μPa [zero-peak sound pressure level: 151 dB re 1 μPa; t90: 126 ms; sound exposure level of a single strike (SELss): 127 dB re 1 μPa(2) s] the porpoise's respiration rate increased in response to the pile driving sounds. At higher levels, he also jumped out of the water more often. Wild porpoises are expected to move tens of kilometers away from offshore pile driving locations; response distances will vary with context, the sounds' source level, parameters influencing sound propagation, and background noise levels.
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Policy development is a dynamic and cyclic process characterised by successive stages of development, implementation and evaluation. Throughout this process, interaction between science and coastal management plays an important role. An illustration is given in this paper, based on an analysis of the history of coastal policy in the Netherlands over the last two decades. Evaluation in 1995 of the coastal policy of Dynamic Preservation, developed during the late 80's and implemented in 1990, led to a redefinition in 2000. Implementation in 2001, of a sustainable coastal policy in the Netherlands with both a small- and a large-scale approach, is the result. The analysis in this paper indicates that the successful development and implementation of coastal policy in the Netherlands, is related to the use of a systematic ‘frame of reference’; characteristics are explicit definitions of both strategic and operational objectives applied in a 4-step decision recipe of (1) a quantitative state concept, (2) a bench marking procedure, (3) a procedure for CZM measures or intervention and (4) an evaluation procedure. Applications of this frame of reference show its high potential to better integrate coastal science and coastal policy and -management and to stimulate co-operation.
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Anthropogenic underwater sound in the seas and oceans is increasing. Phocoena phocoena (harbor porpoise) is sensitive to underwater sound because of its very acute hearing, wide hearing frequency range, and high responsiveness to sounds. The detection of sounds by animals and the degree to which sounds have an effect on animals involve the characteristics of sounds at the source, the propagation of sound between the source and the receiver (the animal), and the hearing characteristics of the receiver. Here, we focus on the hearing properties of Phocoena phocoena, factors affecting sound detection, and effects of detected sounds on the physiology, behavior, and echolocation ability of the species.
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Through an analysis of the interaction between end users and researchers participating in the Eurooean Union-funded CoastView project (EVK3-CT-2001-0054), this article illustrates some of the difficulties associated with end user-oriented research. A way of structuring and focusing discussion between end users and researchers, which was applied and further developed during the course of the project, is suggested as a method to deal with these difficulties. The analysis in this article indicates that successful specialist support of decision making is related to the use of a systematic frame of reference. This involves explicit definitions of both strategic and operational objectives applied in a four-step decision recipe consisting of (1) a quantitative state concept, (2) a benchmarking procedure, (3) a design procedure for measures or interventions, and (4) an evaluation procedure.
Article
In an attempt to test the effectiveness of sounds in deterring harbor porpoises from nets and reducing porpoise bycatch in gill net fisheries, two harbor porpoises, kept in a large floating pen at Neeltje Jans, The Netherlands, were subjected to 3 different underwater sounds. The effect of each sound was judged by comparing the animals' behavior during a 15-min test period with that during a 15-min baseline period immediately before the test and a 15-min recovery period immediately after the test. The effects of the alarms were quantified as the distance between the porpoises' surfacings and the alarm and the animals' respiration rates. Each alarm was tested in two positions in the pen. The behavior observed was related to the sound-pressure-level distribution in the pen. All three alarms: the standard Dukane alarm (a commercially available alarm with a regular pulse interval of 4.3 sec used to deter dolphins from fishing nets), the random Dukane alarm (the same alarm with random pulse interval of between 2 and 30 sec), and the “bird alarm” (a sound from a generator) resulted in increases in both the distance of the animals' surfacings from the alarms and their respiration rates. The standard Dukane alarm and the bird alarm were more effective than the random Dukane alarm in inducing the animals to swim away from the sound source.
Article
Harbour porpoise bycatch may be reduced by deterring porpoises from nets acoustically. In this study, two harbour porpoises were subjected to three acoustic alarms. The effect of each alarm was judged by comparing the animals' position and respiration rate during a test period with that during a baseline period. The XP-10 alarm produced 0.3 s tonal signals randomly selected from a set of 16 with fundamental frequencies between 9 and 15 kHz, with a constant pulse interval of 4.8 s (duty cycle 6%). The 2MP alarm produced 0.3 s tonal signals randomly selected from a set of 16 with similar fundamental frequencies but with random pulse intervals of between 2 and 5 s (duty cycle 8%). The frequency spectra and source levels of the 2MP and XP-10 alarms varied depending on the signal selected. The HS20-80 alarm produced a constant, but asymmetrical frequency modulated sinewave between 20 and 80 kHz with total pulse duration of 0.3 s. with random pulse intervals of between 2 and 5 s (duty cycle 4.6%). The porpoises reacted to all three alarms by swimming away from them and by increasing their respiration rate. The XP-10, which on average had the highest source level, had the strongest effect.