八代海南部におけるクルマエビの水深帯別体長組成，分布および移動について

抄録

The length frequency distribution in different water depth zones, spatial distribution and migration of the kuruma prawn Marsupenaeus japonicus (Decapoda, Penaeidae) were examined in the southern part of the Yatsushiro Sea, southern Japan, using the data obtained from commercial catch, experimental sampling survey and mark-recapture experiment. The Yatsushiro Sea is a shallow semi-enclosed inland sea and a fishing ground of M. japonicus. M. japonicus occurred throughout the year in every sampling area having different water depth range, i.e., Area A, less than 10m; B, 10 to 20m; C, 20 to 50m. However, the body size of M. japonicus was significantly different among these sampling areas. Young individuals with less than 140mm in body length were dominant in Area A. In Area B, middle-sized individuals (120 to 160mm for males and 140 to 180mm for females) were dominant especially during June and October. These individuals were believed to be 1-year-old and recruited from Area A after wintering. They were main target for gill net fishery of Izumi City Fisheries Cooperative Association. In Area C, individuals larger than 140mm in body length were dominant throughout the year. Most of the marked individuals were recaptured within 10 km distance from the release point, suggesting the migration range of M. japonicus after settlement was considerably small in the southern part of the Yatsushiro Sea.