THE AMERICAN CRAB INDUSTRY 623 



Owing to the limited demand for live crabs in Alaska the bulk of the catch is 

 canned and shipped to the United States. 



Most of the crabs caught in California are sold in San Francisco. Portland, 

 Seattle, and Tacoma are other important crab markets on the Pacific Coast. 



Methods of Capturing Alaska King Crabs 



Tangle Nets. These nets are made of 18-thread medium laid cotton netting 

 attached to a 34-inch diameter float and lead hues. The mesh is of 18-inch flat 

 stretch measure. The net is lOM feet deep, 150 feet long on the lead line, and 165 

 feet on the float line. Glass buoys and lead sinkers are used, and the net is anchored 

 at each end so that it hangs loosely near the bottom. The nets are usually set and 

 fished from small open boats, and as many as 20 may be attached and fished 

 together. They are arranged parallel to the shore line or with the prevailing wind 

 and current. 



The crabs become entangled in the mesh and are brought to the surface when 

 the net is lifted at intervals during the fishing period. They are removed by hand, 

 which is costly as it is time consuming, and stored on deck until they are butchered 

 for cooking; the net is then reset for more fishing. 



Trawl Fishing. The otter trawl used in fishing for the king crab varies only 

 slightly from that used for years in taking bottom fish from the North Atlantic. 

 The vessels operating in the Bering Sea area are equipped to handle fish as well as 

 crabs. This type of gear is more eflBcient as it skims the bottom and captures all 

 species of sea animal. When the trawl has been lifted and dumped on deck, the 

 various species are separated and sorted; those suitable for commercial use 

 are saved, and the others are thrown overboard. 



Canning Crab Meat 



In 1945 6,475 cases of rock crab, valued at $214,000, were canned in Maine 

 and Massachusetts. In 1948 no production of canned rock crabs is indicated for 

 these states. The complete statistics for canned crab meat, according to states and 

 areas, are shown in Tables 134 and 135. 



Blue Crab. Canning blue crab has never developed into a sizable industry 

 because of the ready market for crabs in the fresh or boiled condition. The points 

 of production are geographically located near the points of consumption, and a 

 fresh supply is readily available. 



Canning blue-crab meat by the usual processing methods has resulted in a 

 product of inferior flavor and color. Fellers (1936) patented a process for elimi- 

 nating this diflBculty to a considerable extent. He has suggested that the changes 

 are largely the result of a breakdown of the unstable proteins due to the influence 

 of heating. This releases both sulfur and ammonia compounds in the meat during 

 the canning process. The blood of the crab contains a copper compound known as 

 hemocyanin, which reacts with the liberated ammonia and sulfur compounds. The 

 oxidation of these compounds results in the characteristic blue color in the meat. 



The Fellers patent is based on treating the crab meat by dipping it in a brine 

 solution containing lactic acid. The strength of the lactic acid is just suflBcient 

 to insure an acid pH of the meat. Small amounts of aluminum or zinc sulfate 

 are contained in the above brine dip, not in excess of 0.04 per cent. 



The crabs to be canned by this process are selected according to season, sex, 



