REPORT OF COMMISSIONERS OF INLAND FISHERIES. 11 



in many essential respects. A great portion of the vegetable pro- 

 duction of the land is available at once as food for man; practically 

 none from the sea is so utilized. (In Japan, however, the sea- weed is 

 converted into edible form by an industry amounting annually to 

 several million dollars.) The sea food which is available at once 

 for man consists of animals, but the thousands upon thousands of 

 tons of animals produced annually in our own waters and used as 

 food depend, in turn, upon marine plants for their food. Again, as 

 opposed to the conditions upon land, the plants which serve as the 

 bulk of the supply of food are for the most part practically invisible. 

 They are not stationary, attached to the ground, and of considerable 

 individual size, but are floating and microscopic. These vegetable 

 organisms, moreover, are not confined to one surface, as upon the 

 land, but are distributed, though unequally, throughout the whole 

 depth of the waters of the bay. Some idea of the numerical abundance 

 of these plants may be had by those who have seen the phenomenon 

 of "red water" in the upper parts of our bay. The red, soupy appear- 

 ance of the water, miles in extent, has been shown to be due to the 

 abnormal abundance of one species of these swimming microscopic 

 plants which normally occur as one of the invisible components of 

 the plant food of the bay. In samples of red water taken during a 

 visitation of the plague some years ago, it was estimated that there 

 w^ere over five milhons per quart of sea water. 



In every part of the world where a scientific study of the fisheries 

 is pursued, investigation of this microscopic floating population of the 

 sea, under the general name of "plankton,'' is being carried on. 

 Your Commissioners have taken their part in this investigation for 

 the sake of our own interests and are employing, besides the standard 

 methods and apparatus, some other methods peculiarly adapted to 

 the unique advantages of our station. 



The investigation of the conditions which determine the "setting" 

 of clams, oysters, etc., are involved in this plankton work. The 

 solution of these mysteries would be of great economic value. 



