On changing the size selectivity of fishing gear for Chionoecetes opilio in the Japan Sea

At present, management agencies enforce size limit restrictions in the Japan Sea which prevent the landing of male C. opilio less than 9cm carapace width. Since Danish seiners cannot avoid capturing illegal sized crabs, a large number of the crabs are discarded at sea in the hope that they will eventually recruit into the legal size. However, catches of this crab have declined accom-panied by a reduction in average crab size. We demonstrate that crab yield can be increased by switching the gear to long line traps with 15cm streched mesh. Thus, by changing the size selec-tivity of the gear, crabs smaller than 9cm carapace width can be protected from the fishery.