Abstract
Oblong rockfish, Sebastes oblongus, and red spotted grouper, Epinephelus akaara, one of the highpriced fishes, have been released for stock enhancement in Kagawa prefecture in Japan. Released artificial juveniles of these species are easily preyed by predators after release due to their vulnerable characteristics such as sluggish movement and defenseless behavior. This fact have led to poor recovery rate in stocking project of these species artificial juveniles in Kagawa prefecture over the past dozen years. Therefore, we propose the new protective shelter for released juveniles in this study for the sake of avoiding intense predation by overwhelming predators. This shelter also functions as nursery ground with both remarkable amount of adherent prey organisms on the porous substrate and dark comfortable rooms. It is characterized by the size of gaps that small released juveniles can easily hide in and enourmous strong predators hardly sneak into.
