20 REPORT OF THE COMMISSIONER OF FISHERIES. + 
has revealed the cause of death in many cases, and remedial measures 
have been suggested to the superintendents of trout stations. 
Efforts to find a satisfactory food for young salmonoid fishes at a 
lower price than the expensive meat products in general use have 
been continued. Canned herring milt has been found to have some 
value when used in combination with meat, but used alone it has not 
yielded good results, as it appears to lack some important require- 
ment of a full meat diet. 
Climatic conditions during the 1921 nesting season of the basses 
were very unfavorable for a large output of fish. A period of 
unseasonable warmth in March unduly advanced the spawning 
season. This was followed by a cold spell in April and variable 
weather in May, such conditions appearing to prevail all over the 
country. A sudden fall in water temperature invariably causes 
spawning bass to desert their nests, with a subsequent loss of the eggs 
deposited. The bass output was therefore curtailed at practically 
all stations, and at some of them it was a complete failure. 
In cooperation with the fishery authorities of Minnesota, investi- 
gations were made with the view of determining the feasibility of 
making collections of pike-perch eggs in the Rainy Lake region of 
that State. Operations were conducted at two sites, and eggs to the 
number of 13,680,000 were obtained as the Bureau’s share of the 
returns. 
On the Atchafalaya River, in Louisiana, 96,440,000 eggs of the 
buffalofish were taken between February 27 and March 25, 1921, the 
collections being materially reduced below those of the preceding 
year by the short spawning season and the small numbers of fish 
available. These unfavorable conditions are attributed to the late 
rise in the river, which, occurring in January, acted as an incentive 
to the fish to pass by their usual spawning grounds and seek more 
inaccessible spots in the denser portion of the flooded swamps. ‘The 
catch of fish along the river was reported by local fishermen to be the 
smallest since 19138. 
Taking advantage of an opportunity to save eggs of buffalofish 
and carp on the Mississippi River at Bellevue, lowa, and Lynxville, 
Wis., during the spring of 1921, the Bureau collected 68,267,000 eggs 
of the former and 42,712,000 of the latter species, all of them being 
secured from fish caught for the market by commercial fishermen. 
The eggs were fertilized and immediately planted on the spawning 
grounds in the river. 
HATCHING OF MARINE FISHES. F 
Operations in this branch were conducted at the usual points in 
Maine and Massachusetts and were addressed to the cod, pollock, 
haddock, winter flounder, and pole flounder. The weather through- 
out the spawning season of the various species was favorable, result- 
ing in the taking of eggs of better than average quality at a lowered 
cost of production. There was a reduction in the number of cod and 
pollock eggs taken as compared with the previous year. A rather 
sharp decline in the price of pollock deprived the local fishermen of 
an incentive to pursue the fishery, and the catch at Gloucester fell 
off about 70 per cent. The collection of eggs for hatching purposes 
