Snow crab Chionoecetes opilio catches in the western part of Sea of Japan reached their peak in the 1970s. Since then, the catch has been continuously declining to the present, and fishermen have eagerly desired the recovery of its stocks. Therefore, the national government has developed 25 protected areas by 2020 to contribute to the recovery of its stocks.
We attempted to verify the effectiveness of the protected areas by conducting surveys of population density of snow crab using crab cage trap. Survey sea areas were Tajima Protected Area 2 (T-2A), Akasaki Protected Area 2 (A-2A), and Hamada Protected Area 1 (H-1A). Tajima Protected Area 2 was found to be effective in protecting over 12th instar males and mature females. Akasaki Protected Area 2 and Hamada Protected Area 1 were also effective in protecting mature females. These protective effects are thought to be due to the water depth of the protected areas. In addition, most of the snow crabs captured were individuals with a carapace width of 60 mm or more. This result suggested that catching characteristics of crab cage trap were strongly influence.
