Fisheries Acoustics
Fisheries acoustics is the specific application of hydroacoustic methods to fisheries. One of the main concerns of fisheries acoustics is the estimation of biomass, that is the mass of fish or plankton in a body of water.
Abundance and biomass estimation is of deep relevance to both the scientific community and the commercial fisheries.
Two broad areas of application exist and Echoview is popular with scientists in both fields as a mediator between their acoustic devices and final estimates of abundance.
Marine estimation of the abundance of schooling fish or plankton
By transmitting a short pulse of sound beneath a moving vessel, listening to the echoes and aggregating the results, an echogram is produced. On such echograms, schools of fish and/or plankton are easily visible, as is the sea bed. The first challenge that exists is to translate these visible traces, with some foreknowledge of the acoustic properties of the fish or plankton themselves, into an estimate of tonnage in a given school.
The second challenge is to combine what is observed beneath the vessel, with a given survey design and statistical techniques to estimate the tonnage of the fish or plankton in a given area that has been selectively sampled.
Echoview implements industry standard techniques that address both of these challenges, yielding tonnage per unit volume or tonnage per unit surface area as desired.
Freshwater counting of fish
By placing a stationary echosounder on a riverbank which fish swim by, or by sounding beneath a vessel in a lake, individual fish tracks can easily be identified in the resulting echograms. The first challenge is to count fish by distinguishing (as automatically as possible) the tracks produced by fish from the general noise in the acoustic environment and/or debris the in the water. Echoview provides advanced fish tracking tools to address this challenge.
The second challenge is again, to translate the count of what is seen with a given survey design into general estimates of abundance by applying statistical techniques.
At Echoview we are committed to providing state of the art solutions to the fisheries acoustics community and invite participation in the hydroacoustics users forum we host.
One of the leading texts in the field, Fisheries Acoustics by John Simmonds and David MacLennan holds a long-honoured spot on our bookshelves and serves to induct new Echoview staff to fisheries acoustics.
