34 REPORT OF THE COMMISSIONER OF FISHERIES. 
MARINE AND FRESH-WATER INVESTIGATIONS, SURVEYS, AND 
EXPERIMENTS. 
STUDIES OF MARINE FISHES. 
Notwithstanding the ee existence of great marine fisheries and 
the common assumption of their inexhaustibility, the development 
of modern fisheries has been such as to call for the artificial propaga- 
tion of certain species and to create a demand for knowledge of the 
life histories, the habits, and the migrations of the important fishes. 
This knowledge is desired in order that we may determine with what 
impunity the fishing methods may be continually increased in extent 
and thoroughness, or what measures of protection may be appro- 
priate, and so that we may properly appraise the value and the possi- 
pilities of cultural operations as applied to marine species. The 
problem must be approached through a complex but systematic plan 
of study, and final results are not obtainable in a short time. Never- 
theless, the continued collecting of fishes at various places and in the 
different seasons, the persistent application of the methods of modern 
science to the details of structure that may be characteristic of differ- 
ent localities or ages or seasons or that may be indicative of migrations 
or other phenomena of life, and the careful consideration of the 
conditions and results of commercial fisheries will bring us finally to 
the attainment of a degree of precise knowledge that a few years ago 
we could not have anticipated. ‘ 
The investigation of the sea herring, which, as the basis of the 
herring and sardine industries, is one of the most important fishes of 
the North Atlantic coast, has been continued in connection with the 
oceanographic work of the schooner Grampus. The analysis of the 
data gathered has been pushed as rapidly as possible and it is ex- 
pected that the results will be ready for publication within a short time. 
The most important commercial fish of the South Atlantic and Gulf 
seaboard is the mullet. Careful studies pursued through temporary 
services in connection with the Beaufort laboratory have laid a 
definite and necessary basis for more comprehensive inquiries when 
it may be possible to carry them out. It is expected that a detailed 
report of the result of the studies can be published after the conclusion 
of one more season’s work. 
An investigation of the habits and possible races of flounders has 
also been undertaken on the coast of New England, but as the study 
is only in its incipiency and the investigator has not yet been able to 
devote to it his entire time it is not now possible to report a definite 
degree of progress. 
For several years the Bureau has directed attention to the condition 
of the tuna fishery on the coast of southern California, which, with 
the canning industry based upon it, has shown such marked develop- 
ment in the last few years. The fishery and canning industries are 
subject to unfortunate vicissitudes because of the irregular appear- 
ance of the tuna in the waters accessible by the present methods of 
fishery. Nothing of a definite nature has been known as to the 
habits of the tuna, the causes that govern their appearance and dis- 
appearance, the parts of the ocean generally frequented by them, 
or the localities resorted to for purposes of breeding. For nearly two 
years the Bureau has attempted to gain such information as was 
