ECONOMICS OF THE FISHERIES 367 



The infinitesimal smallness of the draft on the waters by our fisheries is 

 further shown by the amount of fertiHzing elements which have been ex- 

 tracted from the water and are contained in fish. At an estimated average 

 content of 3 per cent nitrogen and 2.2 per cent P2O5 (phosphorus pentoxide), 

 fish are considered to be good agricultural fertilizer and have been so used. 

 If the entire production of fish of the United States and Alaska were con- 

 verted to fertilizer, it would provide only 7.4 per cent of the nitrogen 

 (815,000 tons N) contained in the supply of commercial fertilizers allocated 

 to the United States in 1948 by the International Emergency Food Council ''^ 

 and 2.3 per cent of the estimated (1,850,000 tons) phosphate (P2O5) 

 supply.*^ Indeed, the P2O5 supply in 1948 itself nearly equals the total wet 

 weight of our annual fish production (2,250,000 tons 75 per cent water), and 

 the fertilizer elemental fixed nitrogen supply is 36 per cent as much as the 

 total wet weight of all fish produced. At this rate, if the entire catch of fish 

 of the United States and Alaska were used for fertilizer, it would take thir- 

 teen years' fishing to supply one year's requirement of agricultural nitrogen, 

 and forty-two years for the phosphorus. 



If the water over the continental shelf is an average of 50 fathoms or 300 

 feet deep, the 300,000 square miles of area of continental shelf of the United 

 States proper would represent 17,100 cubic miles of sea water, and the 

 150,000 square miles off south and southeast Alaska, 8,540 cubic miles of sea 

 water, a total of 25,640 cubic miles (not including inland fresh water). If 

 we assume an average nitrogen content of 80 mg. N., and phosphorus of 20 

 mg. PvOs per cubic meter, 187 cubic miles underlying 0.73 per cent of the 

 area of surface would contain all the nitrogen and 548 cubic miles underlying 

 2.1 per cent of the area would contain all the phosphorus of our entire 4>4 

 billion pounds of fish per year; at a uniform depth of .01 mile (52.8 ft.) the 

 corresponding areas of water would be 83 per cent of that of Lake Michigan 

 for the nitrogen and 1.7 times that of Lake Superior for the phosphorus. That 

 is to say, the draft on the fertilizer content of the ocean water would be neg- 

 ligible, even if the supply were not continuously replenished by circulation of 

 the water. 



We cannot here discuss in detail the causes of this unfavorable comparison 

 of the yield of the water with that of the land. The difference may be found 

 in part in our failure to make the fullest use of aquatic resources; in another 

 part the great difference may be accounted for by the losses in the numerous 

 steps in transformation of microscopic aquatic vegetation into useful 

 animals. Almost certainly the difference lies, on the one hand, mainly in the 

 controlled restriction of agricultural production to wanted plants and their 

 direct conversion into desirable animals, and on the other, the undirected 

 course of wildlife at sea. In the uncontrolled state on land (as among the 



41. Lodge, F. S., Fertilizers in 1947-48. Chemical & Engineering News, Vol. 26, p. 18-19, 1948. 



