Life History of Swimming Crab in Hiuchi Nada, Seto Inland Sea Estimated from Marking Experiments

Abstract

Investigations into the migratry patterns of the swimming crab Portunus trituberculatus have been necessary for a stock enhancement program. From 1984 to 1989, 1, 161 swimming crabs were marked and released in Hiuchi Nada over different three seasons. Tag recoveries from the three groups were 11.2, 46.6, and 34.7%, respectively. More than 91% of those swimming crabs were recaptured in shallow waters less than 20km from the release sites, and the maximum displacement distance was 47km. The movement showed a hibernation area of 20 to 30m in depth and a spawning migration to shallow waters of less than 10m. No marked crabs were recovered outside of Hiuchi Nada. It is considered that swimming crabs in Hiuchi Nada complete their life-cycle in a narrow area of less than 30 min depth after recruitment to the coastal tideland