1National Research Institute of Fisheries Engineering, Fisheries Research Agency, Kamisu, Ibaraki 314-0408, 2Shimonoseki Research Institute, Nichimo Co., Ltd., Shimonoseki, Yamaguchi 750-1136, 3Aichi Fisheries Research Institute, Minami-Chita, Aichi 470-3412, 4Faculty of Marine Science, Tokyo University of Marine Science and Technology, Minato, Tokyo 108-8477, Japan
We engaged in development of a semi-pelagic/bottom trawl net mainly for off-bottom species instead of demersal species, for coastal trawl boats in Ise Bay, Aichi, Japan. Bottom contact of otterboards could be controlled by changing warp length. The semi-pelagic/bottom trawl net reduces the area where the gear contacts the seabed more than a conventional trawl net when otterboards are kept away from the seabed. The measurement of gear dimensions during towing suggested that the filtered water volume of the semi-pelagic/bottom trawl net was approximately twice that of a conventional trawl net, while the swept area was less.