gQ U. S. BUREAU OF FISHERIES 



studies is to measure the fractions of foods that are utilized after 

 they are ingested by trout. In this work as in all projects involving 

 chemical techniques, progress has been slow owing to the difficulties 

 of the problem and to the deficiency in equipment and trained 

 personnel. 



At the Leetown, W. Va., station, an experiment was conducted 

 with rainbow fingerlings, to test the value of certain commercial 

 feeds in comparison with seal meal and salmon carcass meal manu- 

 factured by the Bureau. The dry foods were first fed at a 30 percent 

 and later at a 40 percent level with beef liver. The fish fed salmon 

 carcass meal rapidly outgrew those on other diets and at the end 

 of the experiment were 42.4 percent heavier than those in the best 

 of the other lots. 



Selective hreeding. — Selected lots of fingerlings were carried 

 through the summer of 1937 at the Pittsford station and the best 

 lots retained for breeding purposes. In the fall of 1937, 50 pairs of 

 the best available 2-year fish were mated and the eggs segregated. 



Owing to the necessity for economy in operation of the hatchery, 

 it has not been possible to obtain maximum growth in the select 

 lots but the effects of breeding are nevertheless manifest in the yield 

 of eggs which averaged 1,370 per pound of fish instead of the usual 

 rate of 1,000 eggs per pound for fish of the same size. 



BASS 



The field studies on smallmouth bass begun in 1936 were continued 

 under the direction of E. W. Surber. These investigations are con- 

 cerned with much the same problems in bass streams as are the trout 

 studies in colder waters. Although, as already pointed out, there is 

 a surprising lack of factual information necessary for the formula- 

 tion of fish management plans for trout waters, the dearth of in- 

 formation concerning bass waters is even more marked. No 

 systematic studies on the activities of bass in natural waters have 

 been feasible throughout the year and there is practically no informa- 

 tion on the normal productivity of bass waters. Although bass are 

 now being propagated on an extensive scale throughout the country 

 there is little evidence that fishing for either large or smallmouth 

 bass has been appreciably improved by stocking. It is probable that 

 natural propagation is more efficient than in the case of trout and 

 that there may be less need for artificial aid. This, however, is a 

 matter that can be determined only by comprehensive and systematic 

 studies carried on continuously over a considerable period. It is for 

 the purpose of securing such basic information that the investiga- 

 tions on bass streams were inaugurated and the results already ob- 

 tained are of great practical value. 



In addition to the two experimental sections previously estab- 

 lished on the Shenandoah River near Berryville, Va., and on the 

 South Branch of the Potomac River near Romney, W. Va., observa- 

 tions were made on sections of similar length in tlie Cacapon River 

 near Largent, W. Va., and the North Fork of the Shenandoah River 

 near Strasburg, Va. Stream conditions were entirely satisfactory 

 for observations on the extent of natural propagation in the South 

 Branch and Cacapon Rivers but in the Shenandoah and its North 

 Fork visibility was much poorer. 



