194 DESCRIPTION OF IMPORTANT FISHERIES AND THEIR PRODUCTS 



Table 14.1. Supply of Crabs and Lobsters in 1960, 

 AND Manufactured Products^^ 



Catch Value Import Manufactured Products 



" Frozen sections in shell. 



* Stone crab, frozen claws. Rock crab products are included under blue crab. 

 « Includes 7,895 cases of canned specialties. 



<* Includes canned meat and specialties. 



* "Standard cases" represent the various size cases converted to the equivalent of 48 cans to the case, 

 each can containing 6i^2 ounces. 



Z Imports include 4,507,000 pounds canned crab, 2,406,000 pounds canned lobster, 533,000 pounds 

 canned spiny lobster. Balance represents fresh or frozen import quantity. 



Exoskeleton. This is a flexible substance composed of the carbohydrate 

 chitin which is reinforced and hardened with calcium salts after each 

 growth molt. The molt cycle produces physiological characteristics of 

 special significance. For example, immediately following the molt, the 

 crab is in a soft shell stage and quite helpless — also in the case of blue 

 crab quite edible. Before the shell hardens it must be enlarged to allow 

 for new growth; therefore, the tissues of the body become engorged with 

 water and expand up to 15 to 20 per cent by volume. Crab taken at 

 this time for commercial purposes tend to be watery, poor in texture, 

 and low in per cent yield of meat per pound of live crabs. Since the molt- 

 ing cycle relates to the mating process, conservation regulations usually 

 set commercial seasons in relation to the cycle. 



Distribution. Crabs maintain a close relation to the coast line and bays 

 with relatively smooth shallow bottoms and tend to move laterally from 

 shallow to deeper water and back during the seasonal cycle. Movement 

 along the coast is not significant in most fishery areas. Lobsters have a 

 similar distribution except that rocky bottoms are preferred for the 

 greater abundance of the food supply and the natural protection provided 

 from predators. This distribution encourages the development of a local 

 inshore fishery with a wide variety of gear to suit individual conditions. 



Appendages. The degree of segmentation and the development of the 

 appendages for walking, swimming, or grasping show a considerable vari- 



