DISTRIBUTION PATTERN AND TERMINAL MOLT SI ZE OF SNOW CRAB CHIONOECETES-OPILIO IN YAMATO-TAI

Eight experimental fishings with crab traps were made to study the spa tial distribution pattern of snow crab Chionoecetes opilio on the bott om of a bank known as the Yamato-tai located in the center of the Japa n Sea. The size of the terminal molt crab was comparatively examined f or three regions, i.e. Yamato-tai in the Japan Sea, coastal waters of the Japan Sea off Kyoto Prefecture, and coastal waters of the Pacific Ocean off Fukushima Prefecture. Adult females were mainly distributed in an area shallower than around 320 m in depth in conditions of a gra dual down ward slope with a muddy bottom. On the other hand, males wer e distributed in all survey areas from 290 m to 349 m in depth. Termin al molt males were divided into five groups with average carapace size s of 64.9 mm, 80.5 mm, 96.4 mm, 110.5 mm, and 125.0 mm. Adult female s izes of terminal molt females was 69.8 mm. These sizes were 10-20 mm s maller than the terminal molt size of crabs obtained from the coastal areas off Kyoto and Fukushima Prefectures.