A Marking Experiment for Kuruma Prawn Penaeus japonicus

A marking method of Kuruma prawn Penaeus japonicus was developed by utilizing the color reduction of their rami (caudal fan). This method was testified for 45 individuals kept in laboratory and 1680 individuals released in the wild. The prawns regenerated their rami but the reduction of the color was visibly recognizable. Larger individuals tended to have more remarkable color reduction compared to smaller ones. This method had negligible effect on the survival or growth of prawns when they were larger than 30mm BL. We applied this method to release-recapture program and estimated recapture rate of the released prawn as 18%.