36 THE WEALTH OF THE SEA 



The sardine pack is very valuable, and about three 

 million cases valued at more than twelve million 

 dollars are canned annually. In Europe, where the 

 people are accustomed to eating salted fish, salting 

 is still the most important means of preserving fish. 

 More than 500,000 barrels of herring are salted 

 annually in Scotland alone. In Europe many smoked 

 fish are also consumed; approximately 200,000 bar- 

 rels of herring alone are preserved by smoking in 

 Scotland. During periods when the supply exceeds 

 the demand, many fish are frozen in America and 

 held until a time when the supply diminishes. In 

 1925, 91,165,068 pounds of fish were frozen. 



The by-products of the fishery industries include 

 several interesting products that have multitudinous 

 uses. The importance of fish-oil and fish-glue in our 

 daily Hfe has already been discussed. Fish waste has 

 been used as fertilizer since prehistoric times. In 

 recent years the oil has been extracted from this 

 waste, which is then dried and sold as meal for 

 animal feed. This change is gradually revolutioniz- 

 ing the whole by-products industry, for meal is worth 

 much more than fertilizer. By feeding meal to his 

 stock, the farmer is able to utilize all of the valuable 

 components of the scrap, for by fertilizing his land 

 with manure from his stock, he uses again much of 

 the nitrogen of the meal which has already served 

 in the nutrition of the stock. 



Shark leather has recently become very popular. 

 Cod, salmon, and other fish skins may be tanned into 

 excellent leather. The air-bladders of the sturgeon, 

 hake, and other fishes are made into isinglass. 



