Effects of Salinity on Biogenic Amines, Hemolymph Osmotic Pressure, and Activity of Gill's Na+/K+-ATPase in Charybdis japonica (Crustacea, Decapoda)

The effects of salinity on hemolymph osmotic pressure, gill Na+/K+-ATPase activity and dopamine (DA), norepinephrine (NE), serotonin (5-HT) in the gills, and hemolymph of the adult Charybdis japonica were studied. DA levels increased significantly (P < 0.05), while the NE and 5-HT revealed contrary change in hemolymph and gills. The iso-osmotic point of C. japonica (911.4 mOsm/kg) was at salinity of 27.87 ppt. The Na+/K+-ATPase activity of gill showed negative correlation with salinity in the hypotonic environment (< 27.87 ppt). The results of this experiment indicated that C. japonica had great capability to acclimate to low salinity.