MEATS AS TROUT FOOD 



143 



value of these two criteria may be open to question. Both the 

 t»;rowth and mortality have been influenced at times by the occurrence 

 of specific infections which have necessitated the adoption of control 

 measures. To what extent these have affected our results we have 

 no means of determining. 



In evaluating a trout food consideration must be given to the 

 possibility that a ration which proves satisfactory under one set of 



5 6 7 8 9 10 II 12 13 14- 15 16 17 18 19 20 21 22 23 



LOT NUWBtR 



Figure 11. — Comparative growth of yoarling brook trout on experimental ra- 

 tions. July 10 to September '2:\, 1929. The mortality in the various lota 

 was so slight as to be of no significance. Vertical columns indicate per cent 

 increase in weight during the course of the experiment. The rations of 

 the individual lots were as follows: l = pig liver, 25; clam meal, 75. 2 = 

 pig liver, 40; clam meal, 60. 3=sheep pluclfs, 40; clam meal, 60. k^ 

 beef melts, 40; clam meal, 60. 5 = pig liver, 25; clam meal, 37i/> ; shrimp 

 meal, 37i/,. 6="fox food," 100. 7 = pig liver, 100. .S=pig liver, 25; dry 

 buttermilk, 37%; shrimp meal, 37%. 9 = beef melts, 25; clam meal, 37% r 

 shrimp meal, 37%. iO = pig liver, 20; sheep plucks, 20; shrimp meal, 60. 

 ii = pig liver, 40; shrimp meal, 60. i2 = pig liver, 40; dry buttermilk, 60. 

 J3=pig liver, 50; beef heart, 50 Ji = pig liver, 40; haddock meal, 60. 

 i5 = pig liver, 40; haddock meal. 30; shrimp meal. 30. ib' = pig liver, 25; 

 haddock meal, 37%; shrimp meal, 37%. J7 = sheep plucks, 40; shrimp 

 meal, 60. JS = pitr liver, 40; soybean meal, 60. /.'» = beef melts. 40; dry 

 buttermilk, 60. 20 = beef melts, 40; shrimp meal, 60. 21 = beef melts. 

 100. 22=pig liver, 40; wheat middlings, 60. 23 = beef melts, 25; haddock 

 meal, 37%; shrimp meal, 37% 



conditions may not show up as well under other conditions. This 

 is a common belief held by trout culturists and is undoubtedly true 

 to a certain extent. It is logical to assume that where environmental 

 conditions are exceptionally favorable less suitable rations can be 

 fed than would be possible where the fish are handicapped by over- 

 crowding or a poor water supply. This is probably the reason 



