Multifrequency echo sounder operation: Discriminating fish species by means of Simrad scientific echo sounders
In cooperation with the Institute of Marine Research in Norway, Simrad has developed an echo sounder system capable of discriminating between different fish species.
Recent research has shown that simultaneous use of several discrete echo sounder frequencies (multifrequency) not only improves fish stock estimates, but can also be used to identify species. This is because each specie has a unique acoustic frequency response. This new and growing understanding greatly improves the value of hydroacoustics to obtain information about marine resources.
Scientists at the Institute of Marine Research, Norway, have shown that different species of zooplankton and fish can be identified based on multifrequency acoustics.
In the future, databases of 'acoustic signatures' for the different commercially interesting fish species will be established and Simrad is already developing echo sounders that can take this information into practical use.
- Single frequency echo sounders have traditionally been used to locate fish resources and to determine their size, both at population and individual level. With the high exploitation rate on limited fish resources seen internationally, selective fishing has become a major topic in fisheries management. Our goal is to provide echo sounders for the international fishing fleet being capable of both species identification and accurate size estimation. Sustainable exploitation of our fisheries resources is dependent on this information and any instrument being capable of providing such information will be a success. Simrad's development for fishery research systems can help the industry as a whole, says Frank Reier Knudsen, fishery research scientist in Simrad.