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open in the other oceans. In fact, the sea is certainly capable of 

 yielding vastly more food to man than at present. Expansion of this 

 sort also offers attractive possibilities for fish products other than 

 food, especially for fertilizer, for stoci food, for oil, for glue, 

 etc. and for fish skins as a source for leather(^is^.^^'-he:^e) in fact the 

 catch of one species alont (the Menhaden) used exclusively for fertil- 

 iser, scrap, and oil along the Atlantic coast of the United States, is 

 about 700,000,000 lbs. yearly. 



In the case of the shell fisheries (for clams, oysters, mussels, 

 abalones, pearl-oysters, etc.) the great problem is to guard against 

 depletion by overfishing, or to maintain the stock by cultural methods. 

 This danger is much more imminent for the molluscs than it is for most 

 of themarine fishes, both because all of the shellfish now used for 

 food live close to shore in shoal water, and because they are so 

 B-:ationary that once a center of abundance is found it is soon fished 

 with great intensity. The result is that the maintenance of the 

 stocks of oysters, cl-ms, abalones, etc. around our coasts is already 

 an urgent matter, and it has been found necessary severely to regulate 

 the pearl fishery, wherever this is carried on in the Indo-Pacific. 

 To emphasize the economic importance of the shellfish (molluscs, 

 lobsters, crabs and shrimps) we may point out that they form about 

 one-fifthl of the total sea foods harvested from the Atlantic Coast of 

 the United States, while oyster shells also yield about 6,000 tons 

 of lime as a by-product yearly. 



-'-Footnote; oysters and clams figured without their shells. 



The stationary nature, however, of the shell fishes, and the 

 possibility of cultivating them, as is now successfully done for 

 clams and oysters, makes it easier to safeguard them than the fishes. 

 But detailed knowledge of their lives and ecological relationships is 

 an absolute essential, not only for cultivation, but equally for regu- 

 lating the catch from grounds, or of species the cultivation of which 

 is not practical. And this knowledge can come only from detailed 

 studies falling in the field of marine physiology. 



In short, every problem of the marine fisheries, except such as 

 center directly around the education of the human palate to appreciate 

 new foods and of human industries to employ raw products from new 

 sources, or around improved methods of distribution, handling, and 

 marketing, is a problem in oceanic biology, just as every problem in 

 plant or animal husbandry on land is one in terrestrial biology: 

 consequently, a problem falling directly within the direct scope of 

 Oceanography. Every such problem demands for its solution precisely 

 the procedure that would be employed had it no economic bearing 

 whatsoever; results gained in any other way can never be better than 

 haphazard; i.e. of the sort proper to a past age. 



This means that whatever marine animal be in question, and what- 

 ever be the question regarding it, an understanding of its whole life 

 cycle is needed for the answer, because only when the whole chain 1e 

 known can we hope to distinguish its strong from its weak links. 

 iTisheries-biologists have long appreciated^this truth. And a growii.g 

 demand for information on such points as spawning grounds, rate of 



