158 BULLETIN OF THE BUREAU OF FISHERIES. 



fish industry in this country, where vast numbers are not only eaten but used to supply 

 classes in zoology or some phase of nature study in nearly every State of the Union. 



Professor Andrews,'' from whose paper the following statistics are taken, thinks 

 that the demand for the fluviatile crayfish is likely to grow steadily, and may help to 

 counterbalance the waning supplies of marine food, especially in the form of lobsters 

 and crabs. 



The crajrfish of the eastern central regions belong to the genus Cambarus, the Poto- 

 mac suppljdng C. affinis; Chicago, C. virilis; New Orleans, C. blandingii; and Montreal, 

 C. bartoni. A considerable fishery for the large and handsome American species of 

 Astacus, a counterpart of the European form, has been developed on the Pacific coast. 

 This centers in Portland, Oreg., where, in 1899, the product reached ir7,696 pounds, 

 valued at $19,556. 



Andrews has shown that the common Cambarus affinis not only breeds annually, 

 but that its young reared from spring eggs may in turn lay eggs the spring following, 

 when under a year old, while at the age of 3% years they attain the average market 

 size of 4 inches. It is further suggested thatTEelarge 6-inch Oregon Astacus, which is 

 more lobster-like in appearance, could doubtless be successfully introduced into Eastern 

 waters, and, with a growing demand, profitably reared, since there is no reason to 

 suppose that climatic changes would offer any obstacle to its development. 



The prawns and shrimps distributed among the various famiUes enumerated are 

 undoubtedly the most active and most graceful, as well as the most plentiful of all the 

 decapod Crustacea. Many species are highly valued as food, and are netted and sent to 

 market in vast numbers over a large part of the world. The most important shrimp 

 fisheries of the United States center in the Coast States of the Gulf of Mexico and 

 Pacific Ocean. 



Among the best-known species in North America are the edible shrimp of the South 

 (Penmus setiferus and P. brasiliensis) , the still more abundant common shrimp {Crangon 

 vulgaris), found on both coasts and closely related to the common European shrimp 

 The California shrimp (Crangon jranciscorum) , the largest and most important of the 

 edible species on the western coast, attains a length of 2i% inches. It not only supplies 

 abundantly the local markets, but occupies an important place in the export trade of 

 San Francisco, being boiled, dried, and shipped to China in large quantities. 



Prawns are extremely abundant in the East Indies from Japan to Australia, and, 

 commercially considered, are the most important Crustacea of the Orient. Thirteen 

 species of the genus PencBus alone are taken in Japanese waters. "They are highly 

 prized and extensively used as food and bait, and dried prawns aimually exported to 

 China amount to about 900,000 kilograms in weight and to about 200,000 yen 

 ($131 ,000) in value. The dried prawns belong almost exclusively to the genus PencBus."^ 



Closely allied to prawns, though placed in a distinct family, are the Alpheidae, of 

 which over 100 species of snapping shrimps belonging to the genus Alpheus and 

 Synalpheus alone have been described. They are essentially tropical, and abound in 



« Andrews, E. A.: The future of the crayfish industry. Science, n. s., vol. xxm, 1906, p. 983-986. New York. 



^Kishinouye, K.: Japanese species of the genus Penaeus. Journal of the Fisheries Bureau, Tokyo, vol. vm, 1900, no. i, p. 1-39. 



