196 DESCRIPTION OF IMPORTANT FISHERIES AND THEIR PRODUCTS 



Food Value of Crabs and Lobsters. Cooked or canned crab and lobster 

 meat are moderately high in protein, 18 to 20 per cent, and total minerals, 

 1.7 to 2.7 per cent ash, and quite low in oil content. A food energy value 

 around 90 calories per 100 gm (about 3.5 ounce) suggests that crab and 

 lobster meat can provide variety in a low calorie diet. Little carbohy- 

 drate, less than one per cent, appears in analysis by difference. The 

 variable and rather high values for sodium, 350 to over 1000 mg per 100 

 gm, reflect the variation in the uptake of salt during brine treatment of 

 the meat in the plant. Data indicate that crab and lobster meat are a 

 reasonably good source for minerals and trace elements. Seagran^^ showed 

 that in raw king crab meat over 24 per cent of the total nitrogen fraction 

 proved to be non-protein nitrogen, thus indicating a possible source of 

 error in calculating protein values. 



The Crab Fisheries 



Three species of crabs dominate the fisheries. The Atlantic coast blue 

 crab (Callinectes sapidus) contributes the largest share. The Dungeness 

 crab (Cancer magister) and the king crab (Paralithodes camschatica) of 

 the Pacific coast and Alaska have each provided approximately 15 to 

 20 per cent of the total catch during the last few years; however, the 

 Alaska king crab catch has shown increasing strength. In 1961 the king 

 crab catch exceeded the Dungeness crab for the first time. Minor species 

 of crab include the rock crab (Cancer irroratus) of New England, another 

 rock crab (Cancer species) of California, and the stone crab (Menippe 

 mercenaria) of the Florida coast. 



The major portion of the crab catch is harvested by means of pots, 

 although a substantial part of the blue crab catch depends on trot lines 

 with baits, dredges, and otter trawls. Otter trawls are used also for a 

 small part of the king crab production. 



Blue Crab. The blue crab (Callinectes sapidus) is a small but very 

 important market crab from 2^.^ to 7 inches in width across the carapace. 

 It is easily distinguished by its blue and green colors and the spikes on 

 each end of the shell. The range of the blue crab is along the Atlantic 

 coast from New Jersey to the northern part of South America. It prefers 

 the shallow salt water with low salinity in bays, sounds, and river chan- 

 nels; however, the female seeks the deeper water offshore during the 

 winter season. The blue crab spawns in the summer and reaches full 

 growth and maturity during the second summer when 12 to 14 months 

 old'^*. During this period the growing crab molts frequently, about 15 

 times before maturity. Large numbers of the young crabs are sought in 

 the spring and summer to provide the peeler crabs which in turn are 

 held for the emergence of the soft-shell crab. The diet of the blue crab 



