Efficiency of Shelters in Reducing Cannibalism among Juveniles of the Marine Blue Swimmer Crab, Portunus pelagicus

Portunus pelagicus is an important crab species for aquaculture in India. Cannibalism during the megalopa and juvenile stages is a major constraint in standardizing the hatchery technology of this species. The present study evaluates the efficiency of various types of shelters in curbing cannibalism in juvenile P. pelagicus. Larvae from eggs of berried females collected from the wild were reared to first crab instars under controlled conditions. They were stocked in 200-l tanks at a density of 10/l with shelters of different materials: (a) nylon mesh netting, (b) seagrass, (c) seagrass and sand, and (d) without any material as shelter. At the end of the experimental period (15 days), the mean survival rates of the juveniles in each treatment were subjected to one-way ANOVA and pairs that significantly differed (p