Field. — Sources of Marine Food 189 



phytoplankton in this connection is absolutely minimal, 

 amounting in any case to nothing more than an indirect 

 significance through the medium of the plankton 

 copepods." 



That detritus is formed so abundantly in the shallower 

 waters of the ocean and constitutes such an important 

 food supply for most of the bottom-inhabiting animals 

 is of great significance in its bearing on the coming 

 science of sea farming. If the investigators of the Dan- 

 ish Biological Station are right in their conclusions con- 

 cerning the importance of detritus as a food for the 

 benthos fauna then we shall have to revise our methods 

 of determining the available oyster, mussel or clam food 

 supply in the waters of a given locality. It also means 

 that the available fields for the cultivation of oysters 

 or other shellfish are far more fertile than we have ever 

 dreamed in the past. The knowledge of the role played 

 by detritus in its relation to the benthos fauna helps us 

 to understand better the phenomenal growth which often 

 takes place in many mollusks in the absence of an 

 abundant supply of plankton. For example many mussel 

 beds are known to yield on an average about 2,000 

 bushels annually and experiments have shown that one 

 bushel of seed clams planted in a barren flat will yield 

 ten bushels of marketable clams one year later. This 

 serves to show what splendid opportunities for increased 

 food production lie within our reach. Between the 

 plankton organisms and detritus there is an inexhaust- 

 ible ultimate food supply which can be quickly and 

 readily converted into a form available for human con- 

 sumption. A partial solution of the problem of the ever 

 increasing high cost of living undoubtedly lies in appro- 

 priating this vast resource for greatly increasing our 

 own food supply. Cultivating the ocean promises to 

 yield the fisherman far greater returns, with less ex^ 

 pense of time and energy, than the farmer is able to 

 produce from the land. Each new discovery in marine 

 biology is making it more clear that for the comfort and 

 economy of the nation we ought to be doing more in 

 the scientific development of our fisheries. 



