Improving acoustical fishing aids for small fishing vessels

This paper discusses the problem of integrating data from the acoustical displays of pelagic trawlers in order to position the net so that the catch is maximised. The associated secondary problem of reducing the number of visual display units (VDUs) in the wheelhouse is also discussed where relevant. In order to help the skipper, an echosounder is used to ascertain the vertical depth of water beneath the vessel (i.e. the freeboard) as well as indicating the position of fish below the keel. In addition, a (horizontal) sonar is used to scan the water for pelagic shoals and a netsonde is used to monitor the fish entering the net. Inevitably, such a catch system is not always efficient but the problem can be eased by judicious positioning of the VDUs in the wheelhouse. A secondary problem associated with the use of the acoustical fishing aids is that of there being too many VDUs or screens in the wheelhouse. It is shown that futuristic solutions will address this problem as well, while traditional ergonomic solutions can only ease the visualisation problem because of the presentation of the data´s output and the lack of interfacing of equipment