Part I.—INVESTIGATIONS CONDUCTED DURING 1926 
INTRODUCTION 
During 1926 the work of the division of scientific inquiry has 
shown, in increasing degree, the effect of the conscious and deliberate 
effort to center attention upon the problems of the fisheries as a 
distinct branch of marine biology. While none of the lines of in- 
vestigation under way in 1925 have been abandoned, no effort has 
been spared to so conduct the work that results of practical benefit 
to the fisheries and to the fishery administrator may speedily be 
attained ; and it is believed that gratifying progress, comparing well 
with that of the past and promising much for the future, has been 
made. 
It should not be understood by this that only temporary and insig- 
nificant problems, bearing solely on immediate needs, have been un- 
dertaken; for it is realized that the big problem that the fishery 
biologist faces—the problem that enlists his deepest concern and 
demands his best effort—is the task of conserving or rebuilding a 
dwindling fish supply. The problem has not always been attacked 
directly, but in all cases a necessary groundwork has been laid as 
the basis for more immediately productive studies in the future. 
The practical utility of the bureau’s investigations is becoming 
more apparent to the public at large, and with public confidence has 
come a demand for additional investigations. The Congress and 
many State fishery departments have responded with greater finan- 
cial support, and as a result it is confidently believed that the 
science of fishery husbandry and the conservation of aquatic resources 
will be advanced more rapidly during the coming years than ever 
before. 
Perhaps the outstanding accomplishments during the past year 
are the development and application of principles of oyster culture 
to the varying conditions found on the Atlantic seaboard, the scien- 
tific regulation of the Alaska salmon fishery, and the development 
of aquiculture as appled to fresh-water fishes. Extensive surveys 
have been made of the oyster industry from Cape Cod through Long 
Island Sound, and on the southern shore of Long Island, in South 
Carolina, Georgia, Mississippi, and Texas; and recommendations on 
which the various States may base an oyster-cultural program have 
been offered. Hydrobiological conditions differ so greatly in the 
various localities that different procedures must be followed to in- 
crease oyster production. ‘There have been discovered great areas, 
now barren, which, without doubt, can be utilized for the production 
of oysters. Other areas, which have been depleted by overfishing, 
can be restocked; and in many cases the yield and quality of beds 
now productive can be increased materially. 
Not only have these field observations been of aid in drafting 
general oyster-cultural programs, but fundamental researches upon 
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