WIDE-BAND SOUNDER FOR FISH SPECIES IDENTIFICATION AT SEA

A brief description is given of both a wideband echo-sounder and data acquisition at sea, Experiments were conducted in the Bay of Biscay al various seasons for four years. Fish species were identified by trawl ing. Only echoes associated with trawl catches that were monospecific were used in the classification analyses. Species discrimination was b ased only on the spectral signature of the echoes and did not take int o account the characteristics of the school shape. A modelling of the power spectrum of the echo was used to limit the spectral signature to a reduced set of parameters that could be used for classification usi ng a neural network. Thirty-six different monospecific schools, includ ing about 900 echoes, were processed. Three species were considered: s ardine (Sardina pilchardus), anchovy (Engraulis encrasicolus), and hor se mackerel (Trachurus trachurus). Classification performance had a su ccess rate as high as 75%. (C) International Council for the Explorati on of the Sea