FISHERY INDUSTRIES OF THE UNITED STATES, 1938 179 
These statistics furnish the biologist with the background upon 
which to base his prediction of future trends and yields. This he 
does by coupling the statistical data with studies of the life history of 
the species. Difficulty is experienced in making these predictions 
because the supply (population) of the species cannot be seen, as is 
the case with farm animals or crops. The more complete and more 
reliable the statistics on yield are, the better foundation the biologist 
has for conducting his studies. The Bureau, therefore, aims to 
obtain a complete picture of each individual fishery to further these 
biological studies. 
ECONOMIC ASPECT 
When the fishery has been conserved, and trends and yields of the 
fishery have been predicted, the problem still remains of supplying 
the fishery trade with the information so essential to the conduct of 
its business activities. In these days of increased competition the 
very existence of the fishery industry must depend upon reliable 
economic and statistical information. Such material has been especi- 
ally valuable during the past few years, when it has been used in 
national planning. The Bureau endeavors to make its statistical 
surveys so complete that the industry and the various governmental 
organizations may turn to it for reliable fishery statistics. 
SURVEYS CONDUCTED 
The statistical surveys during 1938 were conducted under the 
immediate supervision of Edward A. Power, Associate Statistician, and 
the general direction of Fred F. Johnson, Assistant Chief of the 
Division. These surveys included the collection and dissemination 
of statistics of the commercial catch and its value, fishing craft and 
apparatus, and employment in the fisheries. In addition, data were 
collected on employment and compensation of those engaged in, and 
products of, fishery wholesale and manufacturing establishments. 
Surveys were made during the year covering all coastal sections as 
well as the Great Lakes for 1937. Statistics of the fisheries of Alaska 
also were collected by the Division of Alaska Fisheries. A summary 
of the production of the Mississippi River and tributaries for 1931, 
which is the most recent year for which a survey of this section was 
made by the Bureau, is included in Part 2 of this report. ; 
In addition to the above, statistics were collected on the following 
special phases: The landings of fish by American fishing vessels at the 
ports of Boston and Gloucester, Mass., Portland, Maine, and Seattle, 
Wash. (published monthly); catch of mackerel in the North Atlantic 
fishery; cold-storage holdings of frozen and cured fish and amount of 
fish frozen, which are furnished by the Bureau of Agricultural Eco- 
nomics (published monthly); production, consumption, and holdings 
of marine-animal oils of the United States and Alaska (published 
quarterly by the Bureau of the Census); production of canned fishery 
products and byproducts of the United States and Alaska; transac- 
tions on the sponge exchange at Tarpon Springs, Fla.; and the volume 
of the United States foreign trade in fishery products, furnished by the 
Bureau of Foreign and Domestic Commerce. 
