REPORT OF THE COMMISSIONER OF FISHERIES, 11 
service. The Woods Hole (Mass.) laboratory was in operation with 
u small scientific staff in the summer of 1920, but it was impracticable 
to reopen it in the summer of 1921. 
In the last annual report (pp. 22 and 62) reference was made to 
the new building nearing completion at the Fairport (Iowa) station. 
The building was occupied in August, 1920, and has been found ex- 
cellently suited for the purposes of fishery investigations. On two 
occasions during the year it was the scene of conferences of national! 
scope for consideration of questions affecting the conservation of 
resources of interior waters and the application of scientific studies 
to that end. Both conferences, but particularly the one held June 
8-10, 1921, brought together persons of varied interests from many 
States and were most helpful in affecting interchange of ideas and 
promoting harmonious action to the end that more care may be taken 
to insure the permanency of fishery resources. 
PROPAGATION AND DISTRIBUTION OF FOOD FISHES. 
OUTLINE OF THE WORK. 
The fish-cultural activities of the Bureau are directed to the main- 
tenance of the existing aquatic resources of the country and the de- 
velopment of new sources of supply by the stocking of barren waters 
and the introduction of useful species into waters to which they were 
not indigenous. In this work the Federal Government operates 
along the same lines and with the same object as do many of the 
States. Five distinct functions are involved in this service, namely, 
the collection and fertilization of the eggs of food fishes, the incuba- 
tion of the eggs in hatcheries, the feeding and rearing of the young 
of certain species, the distribution of fishes (and, in some cases, 
eggs) for planting in suitable waters, and the rescue of fishes from 
landlocked flood waters of the Mississippi Valley. 
The principal source of the fish eggs handled by the Bureau con- 
tinues to be the commercial fisheries, in which vast numbers of eggs 
that would otherwise be sent to market in the fish and be a total loss 
are obtained for hatching purposes by experienced spawn takers. In 
the case of some important fishes, notably, but not exclusively, the 
salmons of the Pacific coast, where commercial fishing does not ex- 
tend to or is not permitted in the spawning areas, the ripe fish are 
caught in seines or traps and their eggs are removed, the object 
being to bring about a higher percentage of fertilization than is 
possible under natural conditions and to afford to eggs and resulting 
young protection from enemies and physical fatalities during and 
immediately after the hatching period. Eggs in noteworthy numbers 
are obtained also from domesticated fish held from year to year in 
ponds at the stations. 
No material increase in the scope and magnitude of the fish-cultural 
work was possible during the year. With the available operating 
funds remaining the same, the most careful scrutiny of expenditures 
and the closest application of employees to their duties have been 
required to maintain the service at its existing standard of etticiency. 
The fish-cultural operations in 1921 were conducted in 33 States, 
Alaska, and the District of Columbia, and the output reached every 
