462 U. 8S. BUREAU OF FISHERIES 
of young fish, which must be derived from the hatcheries. An in- 
creasing percentage of the output of game fish from Federal hatcheries 
has gone to streams which have been studied, charted, and planned 
as to their carrying capacity, food resources, ete. 
Hatchery policies have been frequently subjected to change through- 
out the past years, although the mechanics and technique of the 
propagation work itself has-changed remarkably little. 
A few years ago there was wide public acceptance of the belief 
that game fish should be planted at legal or adult size. It is now 
realized that in certain sections such practice is absolutely essential, 
whereas elsewhere the planting of smaller fingerlings will give thor- 
oughly satisfactory results. 
In the earlier days of hatchery operations strenuous effort was made 
to secure the greatest possible hatch of the various commercial species, 
both marine and fresh water. This did not stem depletion. In 
many instances the policy of hatching for the sake of hatching alone 
was abandoned. The modern conception of artificial propagation of 
commercial species is to obtain and hatch eggs which would otherwise 
be destroyed in prosecuting a commercial fishery. The fry resulting 
from these eggs are a byproduct recovery and the hatcheries do not 
reach further and attempt to secure eggs which would be hatched 
naturally and normally if the brood fish remained undisturbed. 
The foregoing comments are made to illustrate the fact that the 
hatcheries, the original agencies of Federal fish conservation, are being 
kept in step with new developments and conditions. 
It may also be pointed out that both sportsmen and commercial 
fishing interests frequently call for the establishment of new hatch- 
eries, either by the States or by the Federal Government. It is 
incontestibly true that in certain sections additional hatching facilities 
are urgently needed. There are limits to the economic justification 
for an indiscriminate establishment of new hatcheries, however, and 
good policy requires that many requests for such hatcheries be dis- 
couraged. Fish should be propagated in areas where natural condi- 
tions afford the best facilities for successful hatchery work and also 
where the stream mileage, lake or pond acreage, and intensity of 
fishing presupposes a real need. In many instances what is needed is 
not a new hatchery but additional rearing facilities for a supply of 
fish which may be shipped in from existing hatcheries. 
SPECIES PROPAGATED 
The Federal hatcheries are distributing practically all of the game 
and pan fishes which are of importance to the angler. The list of 
commercial species of fish propagated is somewhat more restricted 
because of the fact that many of these forms have characteristics 
which render them unsuited for artificial propagation methods, at 
least as a practical economic measure. The propagation of com- 
mercial species must always be based upon an abundant egg supply 
which can be collected for incubation at a reasonable unit cost. 
During 1937, 45 separate species were handled at the hatcheries in 
comparison with 43 utilized during the previous year. 
The most important change was the resumption of the hatching of 
striped bass in North Carolina, in cooperation with the North Carolina 
Fish and Game Department. 
