PROPAGATION AND DISTRIBUTION OF FOOD FISHES, 1921, 77 
FOOD FOR BASS. 
One of the principal problems encountered at most of the pond 
fish-cultural stations pertains to a suitable food supply for both 
young and adult bass. At the Cold Springs (Ga.) station fresh 
mullet was for a number of years the staple food for the bass, but 
this material has not given entire satisfaction, and recently the price 
has been prohibitive. Beef hearts and groupers have been tried, but 
the fish show some reluctance in accepting either of these materials. 
More recently pork hearts have been tried with very satisfactory 
results. 
TESTS WITH HERRING MILT AS FOOD FOR RAINBOW TROUT. 
During the past year the bureau has purchased several cases of 
canned herring milt for the purpose of testing its value as a food for 
young rainbow trout. It has been tried at several hatcheries, and 
while the results of the tests made in comparison with other foods in 
more general use are not necessarily conclusive they seem to indicate 
that canned herring milt when used alone is not a satisfactory 
article of diet for young trout, though when used in combination 
with a meat product it may perhaps be considered a desirable article 
for the fish-culturists to keep on hand as an emergency food. It has 
the advantage of being easily prepared, does not “smoke” or discolor 
the water, and will keep for a long period. 
A noticeable feature in connection with this experiment is that 
for a short period—ranging from 10 to 17 days—the fish receiving 
herring milt exclusively appeared to thrive equally as well as those” 
receiving a meat diet and the mortality was not greater, but beyond 
that time the death rate increased so rapidly that in most cases the 
experiments were discontinued, as it appeared that none of the fish 
would survive under the treatment. A change to the usual foods ap- 
pears to have restored normal conditions among the fish. 
The tabulated statement of the results of these tests in feeding 
may be of interest. Rainbow trout were involved exclusively, and 
in each instance the fish had not previously received artificial food. 
RESULTS or TESTS WITH HerriInc Mitt As Foop ror RAINBOW TROUT. 
ERWIN (TENN.) STATION. 
[Test continued for 16 days—2,500 fish per trough.] 
Weight per 1,000 fish— 
Loss per 
Trench Food used te fish 
ber : : At be- (| At Pid Seat during 
; ginning o uring test. 
test. |, Of test. 1" test. 
| 
Ounces. Ounces. | Ounces. | Per cent. 
6 8 2 | 7 
Die ate | Grnitied: herr pam feta e eee onan = | 6 | 7 1 | 214 
