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Listening to Fish
SEA GRANT DIGITAL OCEANS
Passive Acoustic Applications in Marine Fisheries
Building on work pioneered by Sea Grant to yield data for sustainable ocean resources
Contents
The Challenge . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
Bringing Scientists Together . . . . . . . . . . . . . . . . . . . . . . . . . 2
The Promise . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
Applications to Fisheries . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
The Benefits of Passive Acoustics . . . . . . . . . . . . . . . . . . . 11
Research . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12
Estuaries . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12
Continental Shelf . . . . . . . . . . . . . . . . . . . . . . . . . . . 14
Coral Reefs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17
New Technology . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17
A Primer on Techniques . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19
Hydrophones. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19
System Design. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21
The Future of Passive Acoustics . . . . . . . . . . . . . . . . . . . . . 24
Research Needs. . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24
Software Needs. . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26
Hardware Needs . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27
Education and Outreach . . . . . . . . . . . . . . . . . . . . . . . . . . . 29
The Opportunity. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31
Listening to Fish:
An International Workshop on the Applications
of Passive Acoustics to Fisheries
Front cover: cod
Credit:
Tony Hawkins,
University of
Aberdeen
Passive acoustic technologies are those
technologies that enable us to listen to and
record ambient underwater sounds. Such tech-
nologies have existed for decades; however, a
major initiative to develop and promote their
use in fisheries applications and as an impor-
tant new tool for the census and exploration of marine life is now
needed. Given the significant advancement in underwater tech-
nologies, passive acoustic research promises to be an important
new field in fisheries and related areas/disciplines. The ability to
listen to fish and other marine life allows scientists to identify,
record and study underwater animals, even in the absence of
visual information. Coupling passive acoustics with conventional
visual monitoring and sampling techniques provides a powerful
new approach to undersea research. The Sea Grant College
Program has recognized the great potential of passive acoustics
for fisheries and related fields, and has taken a leadership role in
supporting the development of innovative new research programs
using this approach.
1
Scott Holt on pier
listening to fish
Credit: Scott Holt,
University of Texas
at Austin
The F/V Seeker,
Gloucester, MA
Credit: Madeleine
Hall-Arber, MIT Sea
Grant College Program
Listening to Fish: An International Workshop on the Applications of Passive Acoustics to Fisheries
The Challenge
Bringing Scientists Together
On April 8-10, 2002, MIT Sea Grant hosted an international
workshop on the application of passive acoustics in fisheries.
The workshop was held at the Brooks Center,
part of MIT’s Endicott House facilities in
Dedham, Massachusetts. At the workshop,
more than 40 North American and European
experts from fisheries, fish biology, acoustics,
signal processing, underwater technology,
and related fields shared research results,
knowledge and ideas. Fisheries biologists
gained valuable insight through an exchange
of information with scientists experienced in the use of passive
acoustics in marine mammal studies. Participants were also able
to discuss ideas and experiences in hardware and software tech-
nologies. Previously, many of these scientists had been working
in relative isolation with little interaction with colleagues in
North America and overseas.The workshop has already fostered
new domestic and international collaborations in the field. In
Listening to Fish: An International Workshop on the Applications of Passive Acoustics to Fisheries
2
Conference
luncheon
3
short, the workshop confirmed the great potential of passive
acoustics as a research tool for fisheries.
Finally, the workshop allowed extensive discussion of future
research priorities for passive acoustics. Some of the most impor-
tant research initiatives identified by the workshop participants
were: 1) developing a national database of historic underwater
sound archives; 2) establishing a national/international reference
library of fish sounds, which would be guided by an international
panel of scientists; 3) establishing an international research and
training center for passive acoustic applications for fisheries and
marine census; 4) establishing regional "listening-posts" to
monitor fish sounds and promote passive acoustic research; and
5) actively promoting the technology through publications of the
workshop proceedings and related articles.
Listening to Fish: An International Workshop on the Applications of Passive Acoustics to Fisheries
Conference participants
(from top to bottom):
Joseph Blue,Tony Hawkins,
Phil Lobel, Judith Fudge.
Credit: Cliff Goudey,
MIT Sea Grant
4
Workshop Sponsors
The workshop and resulting publications
were sponsored by:
• MIT Sea Grant College Program
•Office of Naval Research (ONR Code
342, Marine Mammal S&T Program)
•Northeast-Great Lakes Center of the
National Undersea Research Program
Travel for some workshop participants
was funded in whole or in part by:
•Connecticut Sea Grant Program
•Florida Sea Grant Program
•Hawaii Sea Grant Program
•Louisiana Sea Grant Program
•North Carolina Sea Grant Program
•South Carolina Sea Grant Consortium
•Texas Sea Grant Program
•Woods Hole Sea Grant Program
Listening to Fish: An International Workshop on the Applications of Passive Acoustics to Fisheries
Credit: Scott Holt,
University of Texas at
Austin
Fish are difficult to see and study in the ocean. While scuba
techniques can help in shallow waters and a range of active
acoustic and optical techniques can assist in deep water, we are
still largely ignorant of the distribution and behavior of the great
majority of marine fish. Possibly one of the greatest challenges to
researchers attempting to study the behavioral ecology of fishes
is finding the fish in the first place. Any tool that can help scien-
tists locate fish is therefore valuable. Fortunately, many fish use
sound to overcome the problem of living in an environment with
limited light and visibility. Fishes produce sounds to communicate
with one another while they are mating or being aggressive,
and they also make noises associated with feeding and swim-
ming. Over 800 species of fishes from 109 families worldwide
are known to be vocal. Of these, more than 150 species are
found in the northwest Atlantic. Among these vocal fishes are
some of the most abundant and important commercial fish
species, including cod, haddock, and the drum fishes.
5
Listening to Fish: An International Workshop on the Applications of Passive Acoustics to Fisheries
The Promise
Fishing boats docked at Gloucester
Harbor, Gloucester, MA
Credit: Madeleine Hall-Arber,
MIT Sea Grant
6
Listening to Fish: An International Workshop on the Applications of Passive Acoustics to Fisheries
Passive acoustic techniques can be used to locate individuals
and concentrations of particular species, especially during their
vulnerable spawning stage. This in turn allows spawning habitat to
be identified,mapped,and protected. Passive acoustics can allow
the numbers of fish to be assessed and can be used to gain a better
understanding of fish behavior, including migrations. Passive
acoustics can also be used to monitor sources of noise pollution and
to study the impact of human activities on marine communities.
Anthropogenic sources of noise pollution include vessel activity, seis-
mic surveys,sonars, oil and gas drilling,and military activities.These all
have an unknown but potentially important impact on marine fish.
The workshop participants believe that passive acoustic tech-
nologies hold special promise and will become important tools in the
coming years. However, these techniques have been largely ignored
in the northwest Atlantic for the study of fisheries resources. Passive
acoustics is also amenable to cooperative research with commercial
fishermen, who can bring their own knowledge to such studies.
Using hydrophones, marine ecologists and fishery biologists
have been able to listen to the sounds fish produce and identify
species-specific and even individual-specific signatures using
signal processing and spectral analysis computer algorithms.
Often, as in the case of the drum family Sciaenidae, these sounds
are very loud and dominate the acoustic environment where
they occur, so much so that they interfere with military and
petroleum prospecting operations that involve acoustic moni-
toring. In other situations, such as with damselfishes on coral
reefs, the sounds are not loud and are detectable only with
specialized techniques.
7
Listening to Fish: An International Workshop on the Applications of Passive Acoustics to Fisheries
Applications to Fisheries
Haddock
Credit: Tony Hawkins,
FRS Marine Laboratory
8
Listening to Fish: An International Workshop on the Applications of Passive Acoustics to Fisheries
Examples of some vocal fish species important to North American Fisheries:
Fish sketches
courtesy of NOAA/NMFS
Northeast Fisheries Science
Center
9
Listening to Fish: An International Workshop on the Applications of Passive Acoustics to Fisheries
To identify the species of fish producing a sound, one first
must do "sound-truthing." There are two principal ways this has
been accomplished: 1) captive fish recordings and
2) in situ (i.e., in the field under natural
conditions) recordings. However, acoustic compli-
cation in a tank or aquarium, combined with
unnatural behavior and sound production, makes
the first approach problematic. Equally severe
problems exist with in situ recording because of
the difficulty in matching sounds to species and
behaviors. Knowledge of sound source levels is
important for calculating the detection limits of
hydrophones. Precise measurement of sound
sources requires knowledge of the location
of the fish and the hydrophone's characteristics. Biologists have
been able to link the aggressive and spawning behavior of fish-
es to their sound production using a combination of in situ and
tank studies. For example, sounds produced by haddock during
Joe Luczkovich monitoring fish
sounds in laboratory
Credit: Joe Luczkovich,
East Carolina University
10
Listening to Fish: An International Workshop on the Applications of Passive Acoustics to Fisheries
courtship and mating have been recorded
and analyzed in this manner. Once the
association of sounds to specific species
and behaviors has been established, passive
acoustics provides a rapid method of estab-
lishing the spawning component of essential
fish habitat (EFH).
Investigators often have used ono-
matopoeic terms such as "grunts," "knocks,"
"snaps," "pops," "staccato," "drumming,"
"humming," "rumbles," "percolating," "purring," etc., to describe
fish sounds. A standardization of these sound descriptions is
needed to allow rapid communication between biologists and
other observers. A less convenient but more robust way of pre-
cisely reporting such sounds is to make a spectrograph or "voice
print" of the sound recording. Similar tools can be used to
identify an individual fish as a method of noninvasive tagging.
Seatrout and its call
types spectrogram
Credit:
R. Grant Gilmore,Jr.,
Kennedy Space Center
•The technique provides a non-invasive, non-destructive census of
marine life.
•It works at night without bias (versus video and other techniques
that require lights).
•It can provide continuous monitoring of fishes.
•It provides remote census capabilities.
•It can determine the daily and seasonal activity patterns of fishes, including
determination of discrete daily spawning times.
•It provides a better foundation for the management of exploited species by
mapping their distribution and pinpointing their spawning grounds.
•It offers a better understanding of the habitat preferences of key fish
species (e.g., essential fish habitat assessment in the U.S.), providing a
better focus for their conservation.
•It establishes baselines for the abundance and distribution of key fish
species, allowing examination of the effects of future environmental change.
•It can help us obtain a wider knowledge of the behavior of those fish that
cannot readily be studied by any other method.
•It can be used to monitor environmental noise and determine its source.
•It can be used to examine the impact of anthropogenic noise on fish,
especially on spawning behaviors.
•Networks of listening posts can provide synoptic data on the occurrence
of fishes and spawning activities on local, regional, national and global
scales.
11
Listening to Fish: An International Workshop on the Applications of Passive Acoustics to Fisheries
The Benefits of Passive Acoustics
Research
Passive acoustic studies using relatively simple techniques
have been successful in locating concentrations of important
fish species, opening the way for further, more detailed studies
of their behavior, distribution and habitat use. Many significant
strides were reported at the workshop in the application of
passive acoustics to fisheries.
Estuaries
•Passive acoustic applications to fisheries were pioneered with
studies of sciaenid fishes (the drum fishes) in estuaries in the
southeastern United States by scientists at the Harbor Branch
Oceanographic Institution. These studies have expanded
into other programs, including studies at East Carolina
University, Louisiana State University, the University of Texas
at Austin, the University of South Florida, Washington College
(MD), the Virginia Commonwealth University, and the South
Carolina Marine Research Institute. This research has demon-
strated the usefulness of passive acoustics as a tool for identi-
fying essential fish habitat and for providing fisheries man-
agers with information on sciaenid reproductive biology.
Listening to Fish: An International Workshop on the Applications of Passive Acoustics to Fisheries
12
R. Grant Gilmore, Jr.
sampling fish sounds
in Florida estuary
Credit:
R. Grant Gilmore,Jr.,
Kennedy Space Center
13
•Researchers have more recently begun conducting passive
acoustic surveys in estuaries of the northeastern United
States. Scientists at the School for Marine Science and
Technology at the University of Massachusetts Dartmouth
and the University of Massachusetts at Amherst have begun
a survey of soniferous fishes of Massachusetts. One early
finding of this program was the discovery that the striped
cusk-eel, Ophidion marginatum, is widely distributed in state
waters, despite previously being thought to range only from
New York to Florida. This study has demonstrated that even
a basic approach to passive acoustics can contribute signifi-
cantly to the census of marine life.
Listening to Fish: An International Workshop on the Applications of Passive Acoustics to Fisheries
Striped cusk-eel
Credit:
Rodney Rountree,
UMass Dartmouth
Continental Shelf
•Passive acoustic applications to continental shelf and open
ocean fisheries have been pioneered in Europe. In an Arctic
fjord in northern Norway, workers from the FRS Marine
Laboratory in Aberdeen and the Fisheries College in Tromsø
have located a spawning ground of haddock, Melanogrammus
aeglefinus. Passive listening has revealed that this species,
previously thought to spawn offshore in deep water, can also
form large spawning concentrations close to shore. The Bodo
Regional University of Norway has used passive acoustics to
monitor vocal activity of Atlantic cod.
•Researchers at the Norwegian Institute of Marine Research
have pioneered the use of remote-controlled platforms
to obtain video and audio data on the spawning behavior
of Atlantic cod and other gadids important in European
fisheries.
•Canadian scientists at Dalhousie University are conducting
laboratory studies of Atlantic cod vocal behavior, while inves-
tigators at the Memorial University of Newfoundland have
begun passive acoustic field surveys for Atlantic cod.
14
Listening to Fish: An International Workshop on the Applications of Passive Acoustics to Fisheries
Gloucester Harbor,
Gloucester, MA
Credit: Madeleine
Hall-Arber, MIT Sea
Grant College Program
Listening to Fish: An International Workshop on the Applications of Passive Acoustics to Fisheries
15
Remote-controlled
instrument platform
Credit: Jan Tore Ovredal,
Institute of Marine Research,
Bergen, Norway. Adapted
for use in this publication.
High-tech scuba
sampling of vocal fish
Reprinted from: Lobel P.
S. 2001. Fish bioa-
coustics and behavior:
passive acoustic detec-
tion and the application
of a closed-circuit
rebreather for field
study. Marine
Technology Society
Journal 35(2)19-28.
•Passive acoustics is being explored as a tool to conduct a
census of marine fishes on the continental shelf of the United
States. In one study at the University of Texas at Austin, a
towed hydrophone array is being used to identify spawning
sites of red drum in the western Gulf of Mexico. In a study
at UMass Dartmouth’s School for Marine Science and
Technology (SMAST), passive acoustics is being used to
catalogue soniferous fishes in the Stellwagen Bank National
Marine Sanctuary. SMAST and MIT Sea Grant Center for
Fisheries Engineering Research (CFER) researchers have also
begun using autonomous archival sound recorders to moni-
tor Atlantic cod and haddock sounds in the Gulf of Maine
and on Georges Bank.
16
Listening to Fish: An International Workshop on the Applications of Passive Acoustics to Fisheries
Coral Reefs
•Although scientists have long studied the vocal behavior of
coral reef fishes, researchers at the Boston University Marine
Program in Woods Hole, Massachusetts have made significant
advances in adapting new technologies to this field, including
the development of the "spawn-o-meter," designed to study
spatial and temporal patterns in fish reproduction. Another
advancement is the use of rebreathers in scuba studies of fish
behavior to avoid adverse acoustic effects of standard scuba
gear. More recently, scientists at East Carolina University and
the National Oceanographic and Atmospheric Administration
(NOAA) Honolulu Fisheries Laboratory have begun studies of
vocal fishes within the Hawaiian Island Reef system.
New Technology
Studies described at the workshop have pushed technology
to new levels that will allow researchers to expand the frontiers
of fisheries science and ocean exploration:
Listening to Fish: An International Workshop on the Applications of Passive Acoustics to Fisheries
17
A variety of fish in a
healthy reef ecosystem
Credit: James P. McVey,
NOAA Sea Grant
•Researchers are beginning to look towards existing acoustic
arrays maintained by the Navy and other agencies for appli-
cations to fishes.
•The potential for combining hydrophone arrays with other
underwater census technologies, including remotely operat-
ed vehicles (ROVs), underwater video, advanced scuba tech-
nologies, and active acoustics is being explored.
•Advances are being made in the development of modeling
tools and software for tracking vocal fish and identifying
individual fish.
•New technologies for detecting and recording underwater
sounds are rapidly evolving.
• Historic archives of fish sounds are being assembled and
rescued from deterioration and will be made available to
researchers and the public through the Internet. This is an
important step toward greater use of passive acoustics in
fisheries science and related fields.
18
Listening to Fish: An International Workshop on the Applications of Passive Acoustics to Fisheries
Joe Luczkovich with
data logger sonobuoy
Credit: Joe Luczkovich,
East Carolina University
Listening to Fish: An International Workshop on the Applications of Passive Acoustics to Fisheries
19
A Primer on Techniques
The success and development of fish bioacoustics depend
on high-quality recording systems and analysis software. It is
especially important that the technology be matched to the
questions being asked. For most questions, the needed technol-
ogy exists for advancing fish bioacoustics, and the main impedi-
ment is insufficient knowledge about using the technology.
Hydrophones
Hydrophones are the most basic element of any recording
system. They are underwater microphones that typically convert
sound pressure into an electrical signal that can be recorded by
a data acquisition system. There are many commercial suppliers
of hydrophones that are appropriate for fish sound recordings.
Data acquisition systems include audio and digital tape
recorders, audio-video recorders, and computers with sound
cards. Digital systems provide obvious advantages over analog
systems in terms of greater frequency bandwidth and dynamic
range and will be the most commonly used systems in the future.
Hydrophone in water
Credit: Tony Hawkins,
FRS Marine Laboratory,
Aberdeen, Scotland
Computer systems that are practical for recordings made in
the laboratory may not be practical in a field situation because
of power and portability issues. Tethered and autonomous
underwater listening stations for monitoring sound-producing
fishes are essential tools for determining which species produce
which sounds, especially for species that are difficult to maintain
in a laboratory tank. Systems that include video imaging are
also useful for documenting behavior of fish aggregations.
Listening to Fish: An International Workshop on the Applications of Passive Acoustics to Fisheries
20
System Design
There are several areas that need particular attention in design-
ing passive acoustic systems for fish monitoring:
•Data compression: Some recorders (such as mini-disc and
MP3) use data compression techniques that alter the recorded
sound frequency and level. These would not be appropriate
for cataloguing known fish sounds, but could be very useful for
ecological surveys of sound-producing fishes.
•Automatic gain control: Many systems (especially many audio
tape recorders and video cameras) use automatic gain control
(AGC) to keep the recorded volume within a prescribed range.
If a system uses AGC, it will not be possible to determine the
received sound level.
•Bit resolution: Systems that record with a higher bit resolution
will have a larger dynamic range (the range of the quietest
and loudest sounds that can be recorded).
•Boat-induced noise: Acoustic and electrical interference,
combined with the physical movement of the boat, can
introduce noise to the recordings.
Listening to Fish: An International Workshop on the Applications of Passive Acoustics to Fisheries
21
Ray Mills, East Carolina
University
Credit: Joe Luczkovich,
East Carolina University
•Dataloggers: Audio dataloggers are useful for recording
over long periods of time in many locations simultaneously.
Computers are the best option for such recording when con-
tinuous power is available. However, this is rarely the
case in field situations, and low-power battery-oper-
ated dataloggers are required. Recent adaptations
of consumer-type high-capacity digital recording
devices offer the low-cost, reliable operation needed
for fieldwork.
•Telemetry: Several types of telemetry systems are
available, including sonobuoys (VHF), cell phone
systems, and short-range microwave systems. All
of these systems require line-of-sight between the
transmitter and receiver, and a relatively high level
of engineering to set up and maintain. Telemetry is
also capable of delivering video to document behavior dur-
ing sound production.
•Satellite telemetry: Over the horizon systems generally do
not support the bandwidth needed for transmitting acoustic
data. However, some amount of preprocessing could allow
data on sound to be transmitted.
22
Listening to Fish: An International Workshop on the Applications of Passive Acoustics to Fisheries
NOMAD technology
Credit: Cliff Goudey,
MIT Sea Grant
•Hydrophone arrays: Multiple hydrophones
can be used for localizing sound sources
and producing a directional receiver
(beam forming) to improve the signal-to-
noise ratio.
•Underwater speakers: Sound sources are
needed for conducting playback experi-
ments to determine the reaction of fish to
different types of sounds. Unfortunately,
frequency response variations of most
underwater projectors require processing of the signals
to produce an accurate reproduction of a fish sound.
•Signal processing software: In addition to commercially avail-
able data acquisition and signal processing products such
as MATLAB (Mathworks, Inc.), there are software packages
designed specifically for bioacoustics research (e.g., Signal,
Canary, and Avisoft).
•Automatic identification: Tools for automatically identifying
species and analyzing long data sets are needed and will
require the development of a library of fish sounds.
Listening to Fish: An International Workshop on the Applications of Passive Acoustics to Fisheries
23
Deployment of remote-
controlled instrument
platform
Credit: Jan Tore Ovredal,
Institute of Marine
Research, Bergen,
Norway
Although studies described during the workshop reflect
the rapid growth of research on passive acoustic applications to
fisheries and marine census, workshop participants identified a
number of areas in which scientific and technical developments
are needed to enhance our understanding of fish and promote
future research:
Research Needs
•Quantifying the size of fish aggregations through a combina-
tion of passive and active acoustics.
• Linking the passive acoustical work to behavioral work (with more
video and audio recordings made together where visibility
allows).
•Modeling the propagation of fish sounds in different environ-
ments.
•Correlating sounds from specific habitats with overall environ-
mental quality.
•Developing directional arrays and beam-forming technologies
to precisely locate the sound sources in dark or turbid waters.
The Future of Passive Acoustics
24
Listening to Fish: An International Workshop on the Applications of Passive Acoustics to Fisheries
Gloucester Harbor,
Gloucester, MA
Credit: Madeleine
Hall-Arber, MIT Sea
Grant College Program
25
Listening to Fish: An International Workshop on the Applications of Passive Acoustics to Fisheries
•Determining the size, sex and maturity of fish producing
sounds.
•Determining what proportion of the fish are calling at a
given time.
•Determining and modeling how sound pressure levels vary
with shoal size and distance from sound source.
•Modeling of chorusing behavior. Are individual fishes calling
together, i.e., are the choruses synchronized?
•Securing funding for establishment of long-term remote listen-
ing stations at established sites so that spatial and temporal
(diurnal and seasonal) variations in sound are characterized.
•Establishing a national center in the U.S. for the study of
bioacoustics of fishes.
•Conducting these studies in ways that will allow testing of
specific scientific hypotheses in collaboration with physical,
chemical, and biological oceanographers.
•Conducting more research on the impact of fishing gear,
boats, pipelines, dredging, petroleum exploration seismic
surveys, and military operations on soniferous fishes.
Software Needs
• Improvements are needed in sound recognition systems.
Such systems would make it possible to automatically
distinguish calls of different species. Advances in the use
of wavelet analysis and other new techniques have already
shown that it is possible to distinguish the voices of individ-
ual male haddock.
•Automatic event detection/analysis software is needed to
quantify temporal patterns of sounds over long time periods.
•Robust software is needed for localization and tracking
of sources.
•Software is needed to allow simultaneous analysis of video
and audio data in behavior studies. This capability would
allow the rapid correlation of individual sounds and sound
components with behavior and functional morphology.
26
Cod and waveform
Credit: Jan Tore Øvredal,
Institute of Marine
Research, Bergen,
Norway
Listening to Fish: An International Workshop on the Applications of Passive Acoustics to Fisheries
Listening to Fish: An International Workshop on the Applications of Passive Acoustics to Fisheries
27
Hardware Needs
• Improved ship-based listening systems are needed, including
dangling and towed hydrophones.
•Bottom-mounted listening systems are needed for determining
the temporal patterns of fish sounds. Robust, low-cost systems
are especially important.
•Drifting sonobuoy systems are needed, either
storing the data, or telemetering data to ships
or shore-based listening stations.
• Large hydrophone arrays are needed to localize
sound sources.
•Systems are needed to measure source levels
and calibrate listening devices so that
researchers can determine the distance
to sound sources.
Cod and cusk being recorded
with the remote-controlled
instrument platform
Credit:
Jan Tore Øvredal, Institute of
Marine Research,
Bergen, Norway
Listening to Fish: An International Workshop on the Applications of Passive Acoustics to Fisheries
28
•Unmanned, archival acoustic recorders are needed for use
on ships of opportunity.
•Systems are needed that allow simultaneous recording of
both audio and video data, including the use of small, quiet
ROVs that can be used from small boats.
•More robust field equipment is needed for shore-based or
small-boat surveys in shallow water and estuaries.
29
Listening to Fish: An International Workshop on the Applications of Passive Acoustics to Fisheries
Education and Outreach
Most fish bioacousticians are biolo-
gists first and engineers second. They
have arrived at fish bioacoustics because
it is a powerful tool for studying fish—
one unmatched by other approaches.
This means that engineering and signal-
processing principles must be learned on
the job.
Unfortunately, there is no one good
source of information about recording and
signal processing that is accessible and
practical for the fish bioacoustician.
Mark Sprague
East Carolina University
Credit: Joe Luczkovich,
East Carolina University
This gap can be bridged both by producing these targeted
materials and conducting training workshops, and by attracting
engineers with a biological interest to the field. The workshop
participants identified a strong need to educate scientists,
managers and the public on the uses of passive acoustic. It
was also recognized that passive acoustics technologies provide
a unique public outreach potential. Scientists and laymen alike
are often fascinated by the phenomenon of underwater sounds.
Passive acoustic technologies are amenable to multimedia
display via the Internet and have great potential as public
education and outreach tools.
30
Listening to Fish: An International Workshop on the Applications of Passive Acoustics to Fisheries
Sebastian Inlet,
Florida
Credit: Mrs.Marge
Beaver
31
Listening to Fish: An International Workshop on the Applications of Passive Acoustics to Fisheries
Research presented at MIT Sea Grant’s April 2002 workshop
underscores the great strides that have been made in the
application of passive acoustics to fisheries and related issues
in the last two decades. It is clear from this body of work that
while passive acoustics is currently underutilized as a research
tool, it is rapidly emerging and holds great promise for the
future. Thus, it is critical that funding agencies be made aware
of the potential of passive acoustics in research on fish and fish-
eries. Passive acoustic approaches can provide fish biologists
and fishery scientists with a non-destructive sampling tool
offering a unique perspective on the biology and ecology of
The Opportunity
soniferous species of fishes. The advances in underwater tech-
nology of the last two decades provide us with an opportunity
to embark on a major new initiative in marine science. Listening
to fish and other underwater sounds should be actively promoted
and incorporated as a standard research tool in marine science.
32
Listening to Fish: An International Workshop on the Applications of Passive Acoustics to Fisheries
Credits:
Edited by Rodney Rountree
1
,Cliff Goudey
2
,Tony Hawkins
3
,Joeseph J. Luczkovich
4
and David Mann
5
1
School for Marine Science and Technology, UMASS Dartmouth, 706 South Rodney French Blvd.,
New Bedford, MA 02744
2
Center for Fisheries Engineering Research, MIT Sea Grant College Program, Bldg. NE20-376, 3
Cambridge Center, Cambridge, MA 02139
3
Environment & Society at the University of Aberdeen, St Mary's, Kings College, Aberdeen, AB24
3UF, UK
4
Institute for Coastal and Marine Resources (Old Cafeteria Complex) Department of Biology
(Howell Science Complex N-418), East Carolina University, Greenville, NC 27858
5
USF College of Marine Science, 140 Seventh Avenue South, St. Petersburg, FL 33701-5016
Special thanks to Diane Rittmuller and Frank "Chico" Smith, School for Marine Science and
Technology (SMAST), UMASS Dartmouth for additional editing support.
Based on the International Workshop on the Applications of Passive Acoustics to Fisheries,
April 8-10, 2002, sponsored by MIT Sea Grant College Program, Office of Naval Research (ONR Code
342, Marine Mammal S&T Program), and National Undersea Research Program, with additional
support from SMAST, UMass-Dartmouth, Connecticut Sea Grant, Florida Sea Grant, Hawaii Sea
Grant, Louisiana Sea Grant, North Carolina Sea Grant, South Carolina Sea Grant Consortium, Texas
Sea Grant and Woods Hole Sea Grant.
Editor: Andrea Cohen, MIT Sea Grant
Design and Layout: Margaret Weigel, MIT Sea Grant
Massachusetts Institute of Technology
Sea Grant College Program
77 Massachusetts Avenue
Room E38-300
Cambridge, MA 02139
http://web.mit.edu/seagrant/
MITSG 03-1
