OCEANOGRAPHY IN THE UNITED STATES 367 



starting with the simplest plants and extending up through the fishes 

 which are harvested by man. 



Sometimes ocean currents are interrupted by islands, and the re- 

 sulting turbulence again enriches the surface layers with deep, en- 

 riched water. In such circumstances, a rich ocean pasture produces 

 an abundance of fish and various forms of plant and animal life. 



The Hawaiian Islands are a good example of that. There are a 

 number of other examples in other parts of the world. 



Oceanography in the broad sense is the study of all natural phe- 

 nomena that take place beneath the surface of the sea, whether they 

 relate to the circulation of the waters, their chemical composition, the 

 contours and structure of the bottom, or the habits and interrelation- 

 ships of the plants and animals that inhabit all levels of this vast do- 

 main. A principal objective of the work of the Bureau of Commercial 

 Fisheries is the maximum utilization of the living resources of the 

 sea, and the Bureau's research program is essentially a program of 

 oceanographic research. 



The marine resources exploited by U.S. fishermen range over vast 

 expanses of ocean, far broader than the narrow band that constitutes 

 the territorial waters of our country. Our salmon resources migrate 

 across the North Pacific and Bering Sea almost to the shores of Asia ; 

 the cod, haddock, and other species that support our great Atlantic 

 trawl fishery are found across the North Atlantic near European 

 shores; the great tuna stocks that are so important to our fishermen 

 range over all the temperate and tropical waters of the world. These 

 fisheries are subject to great fluctuations in abundance from time to 

 time, and these fluctuations are of great concern to our fishing industry. 

 Fishing operations and other human activities, such as dams, pollu- 

 tion, and the like, are responsible for some of these fluctuations, and 

 an important part of our responsibility is to understand these man- 

 made effects, so that their influence upon our economy and upon the 

 welfare of our fishing industry can be minimized or eliminated. But 

 the success of fishing is also affected substantially by natural forces, 

 which may alter the habits of marine animals so that they fail to ap- 

 pear in their usual haunts at expected times, or may influence the suc- 

 cess of spawning to the extent that a year's brood may be many times 

 more, or less, abundant than normal. An understanding of these phe- 

 nomena is essential if our ocean resources are to be exploited efficiently, 

 and for this reason the Bureau is vitally interested in oceanographic 

 research. 



In the brief time available here, it would be impossible to describe 

 all the oceanographic investigations of our Bureau, and I, therefore, 

 propose to confine my remarks to a few of our major investigations. 



The total landed value of U.S. fisheries is more than $350 million. 

 Many different kinds of fishes make up this catch, but shrimp, salmon, 

 tuna, oysters, and menhaden make up almost 60 percent of the total 

 value. Individually, the various species that support the North At- 

 lantic trawl fisheries are not of primary importance, but collectively 

 they also represent one of our major marine resources. When these 

 are added to the five species groups named above, almost 70 percent 

 by value of American fishery landings are included. 



