Potential Applications of Passive Acoustics to Fisheries

Potential Applications of Passive Acoustics to Fisheries.

Applications

Location of calling fishes allows identification of essential fish habitat (EFH)
Continuous monitoring allows determination of daily and seasonal activity patterns
Together with underwater video allows more detailed studies of fish behaviors
Can be used to passively monitor anthropogenic impacts on EFH, and fish reaction to fishing activities
With data on the sound characteristics of specific behaviors, can allow researchers to examine all of the above in regards to a specific behavior (e.g., spawning)
Can be used as a new tool to Census Marine Life
"Backyard science" even low-tech systems can be used to make a valuable contribution to our understanding of the spatial and temporal distribution patterns and behavioral ecology of fishes in both freshwater and marine environments

Advantages

Non-destruction, non-invasive
Inexpensive relative to other technologies
Long-term data acquisition capabilities
Capability of remote monitoring
High profile educational tool, increased public interest, especially when coupled with the internet
Works at night without bias (versus video)
Low tech systems can be used in widespread studies of estuarine, reef and freshwater habitats to allow biological census activities similar to bird watches

What can you do with the data?

Web access to time-lapse or real time fish sounds - education and public interest
Supplement long term monitoring of species diversity, particularly of cryptic soniferous species
Local, regional, national and international networks of "listening posts" can be used to provide synoptic data for the Census of Marine Life
Seasonal temporal patterns of occurrence at a locality (i.e., when species first occur/or first become vocally active)
Daily cycle in vocal activity
Infer temporal patterns of local spawning for species with tight correlations between specific calls and spawning behavior
Monitor temporal patterns in noise pollution at each locality
Monitor sources of noise pollution (passing ships, small boats, trawling, scalloping, other activities can be distinguished)
Examine potential impact of noise pollution on soniferous behaviors such as spawning activity
With a single simple omni-directional hydrophone can get crude indicator of species abundance/spawning intensity (much more information can be derived from more sophisticated array systems)

Limitations

The primary limitation is the detection range - fish can be detected on scales of a few meters to 1 km depending on species and conditions, boats can be detected for up to several km.
Limited availability of reference data for identification of fish species/behaviors based on sound.

Technology/development needs

Establish National Reference Library of fish/animal sounds (underway)
Rescue historical data archives (e.g. Fish and Mowbray 1970) (in progress)
Research to provide field data to validate sound source identity and associated behaviors
Establishment of voucher specimens and their calls in National Ichthyological Collections

Research to quantify sound detection ranges of fishes and other marine animals
Research on light effects on fish behavior by wavelength and intensity (a critical problem for in situ studies of nocturnal behaviors)
Development of local, regional, national and international networks of "listening posts" designed to provide a census of marine life
Software

Automatic species/behavior recognition
Automatic event detection/analysis software to quantify temporal patterns of sounds over long time periods (critical to success of continuous monitoring over intermediate (days to weeks) and long term (months to years) time periods
Real-time detection and processing (e.i.-ii)
Localization/tracking software allowing any size acoustic array and 3-d localization, incorporate (e.i-iii)
For simultaneous analysis of video and audio data on fish behavior, i.e., click on the sound wave of a fish call and go to the corresponding video frame. Needed to allow rapid correlation of individual sounds and sound components with behavior.

Archival acoustic recorders - remote, independent, highly portable for use on ships of opportunity
Sonobuoys with mobile phone, VHS-radio, or satellite data telemetry
Homing devices to locate sound sources for identification and study (major initiative now underway)
Portable, modular hydrophone array systems to allow detailed tracking studies at specific locations/habitats, automatic determination of hydrophone locations and array configuration. Associated GPS/tracking software to allow overlay of environmental data and sound source locations
Recorder allowing simultaneous audio and video data collection - archival or data transfer via tether or telemetry
Hand-held video/audio recorder, GPS, environmental data interface for shore based and small boat applications (recorder is the most difficult component)
Multifrequency, variable intensity light source for various recorders
Miniature ROV designed to obtain video and acoustic data of fish behavior, light-weight, portable and suitable for deployment from shore and small boat

This page was last modified on March 18, 2005