1950 Volume 16 Issue 5 Pages 215-220
The ecology of Calanus plumchrus and Calanus cristatus of Japan Sea and Mutsu Bay was studied and compared. These two Copepods are regular frequenters of Mutsu Bay, and migrates from Japan Sea into Mutsu Bay during April- May. The present result, however, seems to show that at the time of the present collection (March 18th, 1950) C. plumchrus has been accomodated yet in great depth in Japan Sea, whereas C. cristatus already began upward migration, the migration of the latter species seems to take place a little earlier than that of the former.