Indian J. Fish., 48(3): 333-335, Jul.-Sep., 2001 Note Biochemical composition of the deep-water crab Charybdis smithii C.P.BALASUBRAMANIAN AND C.SUSEELAN Central Marine Fisheries Research Institute, Cochin -682 014 ABSTRACT Protien,carbohydrade,lipid,meat and water content of potentially commercial deep-water crab Charybdis smithii were determined for various size groups. The protien content of meat varied from 59.8 to 71.1, lipid from 6.2 to 8.2 and carbo- hydrate from 2.4 to 3.4% of dry weight, whereas, the water content ranged be- tween 85.5 and 89.6%. Deep-water brachyuran crab, Charybdis smithii inhabits the shelf edge, surface and subsurface waters of the oceanic regions of seas around India (Silas, 1969; Sulochananeia/., 1991). The paper, reports the result of a preliminary study of biochemical analysis of C. smithii. Crabs for the present study were obtained during the crusie of the Fishery Oceanographic Research Vessel Sagar Sampada. Specimens were frozen at - 20°C onboard and subsequent analysis was carried out. Only male crabs in the intermoult stage were used for the present study. Carapace of individual crab was removed and meat of all parts including chelate legs was separated and transferred to a petri dish, weighed and its percentage worked out. The tissue was dried in an oven at 60°C until a constant weight was attained and desiccated for two days. 25mg of the dried tissue was added to 1 ml of 10% trichloroacetic acid, centrifuged for 20 minutes at 3000 rpm and precipitate analysed for protein according to Lowry et al. (1951). The supernatant was used for carbohydrate analysis according to Dubois et al. (1956). Total lipid was estimated by sulphophosphovanillin method of Barnes and Blackstock (1973). Water content was determined gravimetrically, the weighed tissue was dried for 48h at 60°C and reweighed. The difference in the weight was taken as water content. Table 1 shows the protein, carbohydrate and lipid content of meat of various size groups. Protein, the major organic constituent in all size groups, varied between 59.8 and 71% of dry weight with a mean of 63.0% (SD=4.1). The maximum protein value was recorded in the size group of 51-55 mm CW and minimum in 56-60 mm CW. Carbohydrate content was very low (2.4 - 3.4%, Mean 2.8%, S.D=0.4). Maximum carbohydrate was obserbved in 61-65mm size group and minimum in 56-60mm size group. Lipid content ranged between 6.2 to 8.2% (mean = 6.9%. S.D.=0.8). The maximum lipid value was noticed in the largest size group of 61 -65mm CW. The meat content of the body varied between 12.2 to 18.6% with a