Digital scientific echosounder is a type of scientific echosounder

Scientific echosounder

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...

 used in hydroacoustic

Hydroacoustics

Hydroacoustics is a general term for the study and application of sound in water. The term comes from Greek υδρο, water, and ακουστική, acoustics...

 research. In a digital scientific echosounder system, the returned acoustic signal is digitized

Digitizing

Digitizing or digitization is the representation of an object, image, sound, document or a signal by a discrete set of its points or samples. The result is called digital representation or, more specifically, a digital image, for the object, and digital form, for the signal...

 for improved performance.

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.

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". 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.