New echo sounder telemetry system for set-net fishery

Set-net is a kind of passive fishing gear. In order to achieve efficient fishing operation, it is necessary to know the amount of fish entrapped before set out fishing. Therefore, remote monitoring of the fishing state in set-net is important. Although there was a telemetry echo sounder system called `telesounder´ used as a remote monitoring tool in set-net fishery successfully, it has been stopped producing and there is no sign that new similar system will spread in set-net fishery. In recent years, with the rapid development of wireless communication technology, remote monitoring of set-net fishing state via 3rd Generation (3G) Network becomes possible. However, echo data from echo sounders are generally voluminous which make it impractical to transfer all the raw echo data via 3G Network. In order to apply 3G Network in the remote monitoring of set-net fishery smoothly, we developed a new echo sounder telemetry system and proposed a fish echo extraction method base on image processing which can largely reduce the data volume to be sent and show good quality echogram-like displays to fishermen. A sea trial experiment has been conducted to verify the functions and capabilities of the new system.