Scientific echosounder
Encyclopedia
A scientific echosounder is a device which uses SONAR
technology for the measurement of underwater physical and biological components—this device is also known as scientific SONAR. Applications include bathymetry
, substrate classification
, studies of aquatic vegetation, fish
, and plankton
, and differentation of water mass
es.
, further enhancing the reliability and precision with which these systems operate. Modern scientific echosounders are reliable, portable, and relatively easy to use.
Collected acoustic data is "stamped" with geographic information for precise positional information (coordinates and time). This enables analysis and incorporation of the results into a Geographic Information System
(GIS) for further analysis, correlation with other variables, mapping, and display.
Currently, the only three manufacturers of scientific-quality digital echsounders commonly used for resource assessment are BioSonics, HTI (Hydroacoustic Technology, Inc.) and Simrad. Other specialty manufacturers of scientific quality echosounders exist.
Features of modern digital scientific echosounder technology include:
Bathymetry
: the depth (range) of the bottom of the river, lake, or ocean below the transducer.
Range : the distance between the transducer
and the "target" (fish, zooplankton, vegetation, bottom). This is determined by precise timing from sound generation to sound reception (by the transducer).
Bottom type; Seabed
type; Substrate type; or Sediment
type : can be assessed and classified (e.g., sand, rock, soft mud, hard mud).
Fish quantity : can be estimated and reported as numbers of fish or biomass
.
Fish size : can be determined in a relative manner, based on acoustic "target size".
Fish behavior : can be assessed through a combination of instantaneous and temporal measures and observations. Spatial distribution, size distributions, diurnal activity, predator-prey relationships, migration rates, temporal activity, etc. can be observed and quantified.
Submersed aquatic vegetation; Submerged aquatic vegetation; or SAV : can be detected and assessed for location, density, and height.
Fish passage : can be quantified for fish movement past a fixed-location hydroacoustic monitoring system. Examples include: Migrating salmon or fish entrained by water intakes.
Data collected with a scientific echosounder can be analyzed for the presence, abundance, distribution and acoustic characteristics of such variables as: depth (bathymetry), bottom substrate class (e.g., sand, mud, rock), submersed aquatic vegetation (SAV), and water column scattering (fish and plankton). Resulting analysis can be used to generate GIS data layers for these variables.
agencies such as the membership of ICES
and the United States National Marine Fisheries Service
(NMFS) commonly use scientific sonar for stock assessment purposes, such as herring biomass assessment for resource management purposes.
More recently, the acoustic data collected has been valuable in underwater habitat assessment and classification for the variables; seabed type (e.g. rock, mud, sand) and submersed aquatic vegetation and algae - with the appropriate software.
Hardware
Software
Sonar
Sonar is a technique that uses sound propagation to navigate, communicate with or detect other vessels...
technology for the measurement of underwater physical and biological components—this device is also known as scientific SONAR. Applications include bathymetry
Bathymetry
Bathymetry is the study of underwater depth of lake or ocean floors. In other words, bathymetry is the underwater equivalent to hypsometry. The name comes from Greek βαθύς , "deep", and μέτρον , "measure"...
, substrate classification
Seabed
The seabed is the bottom of the ocean.- Ocean structure :Most of the oceans have a common structure, created by common physical phenomena, mainly from tectonic movement, and sediment from various sources...
, studies of aquatic vegetation, fish
Fish
Fish are a paraphyletic group of organisms that consist of all gill-bearing aquatic vertebrate animals that lack limbs with digits. Included in this definition are the living hagfish, lampreys, and cartilaginous and bony fish, as well as various extinct related groups...
, and plankton
Plankton
Plankton are any drifting organisms that inhabit the pelagic zone of oceans, seas, or bodies of fresh water. That is, plankton are defined by their ecological niche rather than phylogenetic or taxonomic classification...
, and differentation of water mass
Water mass
An oceanographic water mass is an identifiable body of water with a common formation history which has physical properties distinct from surrounding water...
es.
Technology
Scientific echosounder equipment is built to exacting standards and tested to be stable and reliable in the transmission and receiving of sound energy under the water. Recent advances have led to the development of the digital scientific echosounderDigital scientific echosounder
Digital scientific echosounder is a type of scientific echosounder used in hydroacoustic research. In a digital scientific echosounder system, the returned acoustic signal is digitized for improved performance....
, further enhancing the reliability and precision with which these systems operate. Modern scientific echosounders are reliable, portable, and relatively easy to use.
Collected acoustic data is "stamped" with geographic information for precise positional information (coordinates and time). This enables analysis and incorporation of the results into a Geographic Information System
Geographic Information System
A geographic information system, geographical information science, or geospatial information studies is a system designed to capture, store, manipulate, analyze, manage, and present all types of geographically referenced data...
(GIS) for further analysis, correlation with other variables, mapping, and display.
Currently, the only three manufacturers of scientific-quality digital echsounders commonly used for resource assessment are BioSonics, HTI (Hydroacoustic Technology, Inc.) and Simrad. Other specialty manufacturers of scientific quality echosounders exist.
Features of modern digital scientific echosounder technology include:
- Low side-lobe transducers
- Simple data collection
- Low system noise
- Wide dynamic range
- High system stability
- High accuracy
- Easy system expansion
- Multiplexing systems (multiple transducers can operate simultaneously on the same system)
Scientific software for analysis of hydroacoustic data
Specially written software is available for analysis of hydroacoustic data for assessment of underwater physical and biological characteristics. "Fish" here can apply to any "target" in the water column, e.g., fish, plankton, squid, mammal. All results can be imported into a GIS for additional analysis, correlation with other variables, mapping, and display.Bathymetry
Bathymetry
Bathymetry is the study of underwater depth of lake or ocean floors. In other words, bathymetry is the underwater equivalent to hypsometry. The name comes from Greek βαθύς , "deep", and μέτρον , "measure"...
: the depth (range) of the bottom of the river, lake, or ocean below the transducer.
Range : the distance between the transducer
Transducer
A transducer is a device that converts one type of energy to another. Energy types include electrical, mechanical, electromagnetic , chemical, acoustic or thermal energy. While the term transducer commonly implies the use of a sensor/detector, any device which converts energy can be considered a...
and the "target" (fish, zooplankton, vegetation, bottom). This is determined by precise timing from sound generation to sound reception (by the transducer).
Bottom type; Seabed
Seabed
The seabed is the bottom of the ocean.- Ocean structure :Most of the oceans have a common structure, created by common physical phenomena, mainly from tectonic movement, and sediment from various sources...
type; Substrate type; or Sediment
Sediment
Sediment is naturally occurring material that is broken down by processes of weathering and erosion, and is subsequently transported by the action of fluids such as wind, water, or ice, and/or by the force of gravity acting on the particle itself....
type : can be assessed and classified (e.g., sand, rock, soft mud, hard mud).
Fish quantity : can be estimated and reported as numbers of fish or biomass
Biomass
Biomass, as a renewable energy source, is biological material from living, or recently living organisms. As an energy source, biomass can either be used directly, or converted into other energy products such as biofuel....
.
Fish size : can be determined in a relative manner, based on acoustic "target size".
Fish behavior : can be assessed through a combination of instantaneous and temporal measures and observations. Spatial distribution, size distributions, diurnal activity, predator-prey relationships, migration rates, temporal activity, etc. can be observed and quantified.
Submersed aquatic vegetation; Submerged aquatic vegetation; or SAV : can be detected and assessed for location, density, and height.
Fish passage : can be quantified for fish movement past a fixed-location hydroacoustic monitoring system. Examples include: Migrating salmon or fish entrained by water intakes.
Data collected with a scientific echosounder can be analyzed for the presence, abundance, distribution and acoustic characteristics of such variables as: depth (bathymetry), bottom substrate class (e.g., sand, mud, rock), submersed aquatic vegetation (SAV), and water column scattering (fish and plankton). Resulting analysis can be used to generate GIS data layers for these variables.
Applications
Scientific echosounders are commonly used by International, Federal, State and Local government and management agencies, as well as private-sector consultants working for these public agencies. Academic institutions have realized and are teaching the value of sampling non-invasively with sound to enhance both the spatial coverage and objectivity of fisheries sampling. Fisheries managementFisheries management
Fisheries management draws on fisheries science in order to find ways to protect fishery resources so sustainable exploitation is possible. Modern fisheries management is often referred to as a governmental system of appropriate management rules based on defined objectives and a mix of management...
agencies such as the membership of ICES
Ices
Ices may refer to:*Frozen desserts, particularly within the United Kingdom*Frozen volatiles, in the context of astronomy and planetary science*Phases of iceICES may stand for:*Inflight Crew Escape System, in the Space Shuttle...
and the United States National Marine Fisheries Service
National Marine Fisheries Service
The National Marine Fisheries Service is a United States federal agency. A division of the National Oceanic and Atmospheric Administration and the Department of Commerce, NMFS is responsible for the stewardship and management of the nation's living marine resources and their habitat within the...
(NMFS) commonly use scientific sonar for stock assessment purposes, such as herring biomass assessment for resource management purposes.
More recently, the acoustic data collected has been valuable in underwater habitat assessment and classification for the variables; seabed type (e.g. rock, mud, sand) and submersed aquatic vegetation and algae - with the appropriate software.
See also
- Echo sounder
- FishfinderFishfinderA fishfinder is an instrument used to locate fish underwater by detecting reflected pulses of sound energy, as in SONAR. A modern fishfinder displays measurements of reflected sound on a graphical display, allowing an operator to interpret information to locate schools of fish, underwater debris,...
- HydroacousticsHydroacousticsHydroacoustics is a general term for the study and application of sound in water. The term comes from Greek υδρο, water, and ακουστική, acoustics...
- SonarSonarSonar is a technique that uses sound propagation to navigate, communicate with or detect other vessels...
- Underwater acousticsUnderwater acousticsUnderwater acoustics is the study of the propagation of sound in water and the interaction of the mechanical waves that constitute sound with the water and its boundaries. The water may be in the ocean, a lake or a tank. Typical frequencies associated with underwater acoustics are between 10 Hz and...
External links
Hardware
Software
- Echoview
- Sonar4 and Sonar5-Pro
- L-trippel-S
- BioSonics Visual Analyzer ("fish"), EcoSAV (vegetation), and VBT (substrate classification)
- QTC Impact (substrate classification)