PROPAGATION AND DISTRIBUTION OF FOOD FISHES, 1921. 

 FOOD FOR BASS. 



77 



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 

 3'oung 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 j^oung trout, though when used in combination 

 with a meat product it may perhai)s be considered a desirable article 

 for the fisli-culturists to keep on hand as an emergency food. It has 

 the advantage of being easily ])repared, does not "smoke" or discolor 

 the water, and will keo|) 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 apjieared to thrive e^jually 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 tliat none of the fish 

 would survive unrler the treatment. A change to the usual foods ap- 

 pears to liave restored normal conditions among the fish. 



The tabulated statement of the results of these tests in feeding 

 may be of interest. Kainbow trout were involved exclusively, and 

 in each instance the fish had not previously received artificial food. 



Results of Tests with Heubi.ng Milt as Food fob Rainbow Teout. 



ERWIN (TENN.) STATION. 

 ITest continued for 16 days — 2,500 fish per trough.] 



