202 THE WEALTH OF THE SEA 



mixed with ozone is blown by powerful fans. The 

 ozone partially sterilizes the fish and thus increases 

 their keeping qualities. 



Fish Canning 



Although canning is a relatively modern means 

 of preserving fish, it is already the most important 

 method employed in America, and is gaining in im- 

 portance in several other countries. Canned salmon 

 is by far the most important American fishery prod- 

 uct, the annual pack being valued at about fifty 

 million dollars. American sardines are not known the 

 world over as is salmon, yet the canneries receive 

 about thirteen million dollars for their annual pro- 

 duction. Much tuna and shrimp and large quantities 

 of crabs, clams, and oysters are also canned in the 

 United States. 



Sardines, mackerel, anchovies, herring, tuna, and 

 certain fish roes are canned in various ways in sev- 

 eral European countries, while salmon and swordfish 

 are canned in Japan and along the Asiatic coast. 

 Much salmon is also canned along the Canadian 

 Pacific coast. 



Recently fish canning has gained a foothold in 

 Portland, Maine, and in Gloucester, Massachusetts, 

 two of the leading fish salting and smoking centers. 

 Many kinds of prepared cod and haddock products 

 are now canned, and canned alewives and shad are 

 increasing in popularity. 



No consideration of fish canning would be com- 

 plete without a consideration of the salmon-canning 



