INTRODUCTION 
The fundamental objectives and general characteristics of the re- 
search activities of the Division of Scientific Inquiry have been pre- 
sented at considerable length in the previous annual reports of 
“Progress in Biological Inquiries” together with detailed reports of 
the individual research projects. The underlying philosophy of 
fishery conservation based on a continually growing body of scientific 
knowledge is now so well understood and the program of investiga- 
tion under way during the past decade has justified itself so com- 
pletely, both in its theoretical aspects and its practical applications, 
that it has acquired a momentum that in itself is a protection against 
irresponsible diversion of interest or activity into byways of local 
application or temporary value. A lengthy introduction to the 
major purposes of the various investigations reported in detail herein 
is therefore unnecessary. 
Each of the recent years has seen the development of new projects 
of investigation that contribute to a well-rounded scientific program 
designed to afford still more complete answers to the original ques- 
tions as to “what diminution in the fish supply of our coastal and 
inland waters has occurred, to what causes the same may be due, and 
what remedial measures may be adopted?” With the passing of the 
years new techniques of investigation have been developed or have 
been adapted from other fields of scientific endeavor. New concepts 
of the reactions of marine fish populations to commercial fishing have 
developed and new knowledge of the natural requirements of fish in 
inland waters and of means of their management for sustained yield 
has accumulated. 
Time has also permitted the ripening and the fruition of a series of 
fishery investigations, always time-consuming, so that during the 
ear a number of definitive reports have been completed which, it is 
oped, will be published in the near future. At the same time, and 
coincident with economic recovery, additional appropriations during 
the past few years have permitted the undertaking of new projects, 
bringing to hitherto neglected fisheries the benefit of research and 
the examination of their abuses or deficiencies and paving the way for 
their ultimate rehabilitation and protection. 
During 1938 a new project of considerable magnitude was under- 
taken by the Division—an investigation of the red-salmon fisheries 
of Bristol Bay, Alaska. One of the richest and most productive red- 
salmon fishing areas in the world, Bristol Bay, an arm of Bering 
Sea in western Alaska, receives endless replenishment from the 
spawning grounds of five major tributary river systems. The fishery 
there has developed over many years until it reached a reasonably 
stable maximum at the beginning of the past decade. Three years 
ago, however, the fishery was menaced by an exploration seeking to 
establish commercial fisheries on the high seas to intercept the run 
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