TROUT FEEDING EXPERIMENTS 



By Chas. O. Hayford 

 Superintendent State Hatchery, Hackettstown, Nezv Jersey 



In the accompanying tables an attempt has been made to in- 

 dicate as clearly and concisely as possible, the results obtained 

 from some experiments in the feeding of fingerling brook 

 trout (Salvelinus fontinalis) and brown trout (Sahno fario) 

 conducted at the hatchery operated by the State of New Jersey 

 at Hackettstown. The work was carried on under the imme- 

 diate supervision of Robert W. Hodgson, chemist, formerly 

 instructor in bacteriology and assistant to Prof. William F. 

 Foster in pathological and bacteriological work at the A, E. F. 

 University, France. 



A large stock of trout is constantly maintained at the 

 Hackettstown hatchery, the fish varying in age from newly 

 hatched fry to adults two and three years old. To feed this 

 large stock, from 75 to 100 tons of meat products and fish are 

 required annually; and it was for the purpose of determining 

 the relative values of the different articles used as fish food, and 

 by a comparison of prices to effectuate a possible reduction in 

 the maintenance cost of the fish, that the experiments were un- 

 dertaken. Careful arrangements were made to hold all the fish 

 involved in the experiments under identically similar conditions, 

 in order that any possible variation in the results might be at- 

 tributed solely to the kind of food used. Nursery troughs of 

 the same size were used, each being supplied at uniform rate 

 with an independent flow of water from the same source. The 

 water used was derived from five springs with a minimum flow 

 of two and one half million gallons per day. A chemical and 

 gas analysis of the water gave the following results : 



Parts per million 



Chlorine 11.5 



Alkalinity 129.0 



Total hardness ( Soap method) 162.5 



Total solids 175. 



Mineral residue 152. 



Loss on ignition 23. 



Carbon dioxide 4.2 



Oxygen (66% saturation at 51° F.) 7.5 



