612 MARINE PRODUCTS OF COMMERCE 



Alaska King Crab 



The Alaska king or Japanese crab is the term applied to the genus Parcdithodes, 

 made up of 3 species: P. camtchatica, P. brevipes, and P. platypus. Although the 

 canned Japanese crab pack contained about 8 per cent of 2 additional species, 

 these are not found in Alaskan waters. The crabs are located both north and south 

 of the Aleutian Islands, but the greatest populations are in the Bering Sea to the 

 north. These are, by far, the largest crabs, averaging about 12 pounds in weight 

 and from SVz to 4 feet from tip to tip of the legs. The carapace is small in compari- 

 son to the legs, which often results in its being referred to as the "spider crab"; 

 this is incorrect as the "spider crab" is entirely diflFerent and unfit for food. The 

 carapace measures between 7 and 9 inches, and is covered with spines, the number 

 of which are employed as a means of species identification. 



This group of crabs grows very slowly and requires 9 to 10 years before reaching 

 sexual maturity. They inhabit cold water on a mud and sand bottom at a depth 

 of from 100 to 125 fathoms, where the temperature ranges from 35 to 50° F (from 

 3 to 10° C). In 1939 Japanese canners exported about 55 per cent of their pack 

 to the United States; from 1924 to 1941 this amounted to a total of 3,288,997 

 cases of 48 1-pound cans. 



Composition 



Feller and Parks (1926) found the composition of the Japanese or Alaska king 

 (P. camtchatica) and dungeness crab meat to be as follows: 



Japanese Dungeness 



Life History of the Blue Crab 



The young of the blue crab (Callinectes sapidus) are hatched from very small 

 eggs which are attached during incubation to small hairs on the inner branches 

 of the swimmerets on the under side of the abdomen of the female. The eggs are 

 yellow or orange when first laid and become almost black as hatching time 

 approaches. The entire large yellowish mass of eggs is called a sponge and con- 

 tains from 1,750,000 to 2,000,000 eggs, each about Moo of an inch in diameter. 

 These eggs hatch after about 15 days' incubation. After hatching, the young crabs 

 pass through 2 free-swimming stages. During the first stage the young crab is 

 known as a zoea and little resembles the adult. The body is somewhat cylindrical 

 in shape, the eyes are large and conspicuous, and the spines at the sides are short; 

 there is a long curved spine on the back and the claws are lacking. The zoea has 

 a long sharp beak, 2 pairs of antennae, and 4 pairs of leglike appendages. During 

 this stage the young crab moults about 6 times. In the second stage the young 

 crab is known as a megalops. The megalops more nearly resembles the adult, 

 having a rather flattened body and a shorter and wider abdomen than the zoea. 



