284 



BULLETIN OP THE BUREAU OF FISHERIES. 



But the day when we shall know enough to figure out proper rations is far in the 

 future, and in the meantime every effort should be made to find better foods for growing 

 fishes. There is no reason why we should feed flour and liver forever without knowing 

 why. The recent work of Atkins (1908) in which trout were reared on fly larvse is very 

 suggestive and should be extended. There is no reason why other "natural" foods 

 should not be fed to growing fishes in hatcheries. Entomostracans are easily collected 

 in quantities with a pump or tow net. At some hatcheries (Lyell, 1902) they have been 

 collected at intervals and fed to fry with good results. There is no reason why insect 

 larvae, snails, amphipods, earthworms, and other abundant living foods should not be 

 more generally collected or reared as food for young fishes. 



Table i. — Summary op Fish Foods. 



[.\1I figures concerning food mean percentages by volume. In the "habitat" column the significance of the numbers is as 

 follows; I, aquatic vegetation along shore; 2, sand and pebble beaches; 3, rock beaches; 4. bottom of lake everywhere; s, 

 surface of lake along shore; 6, surface of lake everywhere; 7. open lake; 8, swamp; 9. mouths of streams; 10, river; 11, small 

 ponds; and 12, small streams. These numbers refer to places where collections were actually made; not to the habitats as 

 indicated by the food. The habitats occurring with the greatest frequency are placed first.] 



Total number of fishes examined, 1.576: Toad eggs, o j; fishes, 13.5; insect larvse. 24.8; insect pupa, 6.3; adult insects, 5.2; 

 irhniH<; n.e- larcr(» Crn';fjirpa. iii- Entomostraca, 19.1; MoUusca, 2; Oligochaetes, 3.5; leeches, 0.4; rotifers, 0.2; plants, 4.2; 



- Aijuai Liumuer 01 nsaes examinee 

 hydrachnids. 0.5; large Crustacea, 13.3 

 debris, etc., 2.6. 



