252 American Fisheries Society 



As the materials in most general use for the fish food at the 

 Hackettstown hatchery are pork melts, sheep plucks, beef liver, 

 and butterfish, these articles, either singly or in combination, 

 were the ones principally considered, though certain insects 

 and their larvae were introduced. The average cost per pound 

 of the different articles used is as follows: Beef liver, 13 cents; 

 sheep plucks, 5 cents; pork melts, 3 5^ cents; and butterfish, 4 

 cents. It is difficult to estimate the cost of maggots, but since 

 waste material was used in their production it is safe to say that 

 the cost was low. 



As it appeared important that each lot of fish should be uni- 

 form in size and weight, they were carefully graded as to size 

 before being placed in the troughs selected. Several lots from 

 each trough were then weighed and the average weight from 

 each trough recorded. In weighing the fish, a uniform method 

 was followed throughout the course of the tests, and the aver- 

 age weight of each lot of fish was obtained and recorded every 

 ten days. Two waxed paper cups were filled with water and 

 balanced on a standard laboratory scale. The fish were taken 

 from the troughs with a small dip net and allowed to drain for 

 one minute. They were then transferred to one of the cups and 

 weighed. By exercising care, there was no loss of weight 

 through splashing or slopping of the water. 



Feeding occurred twice each day, the daily ration of food 

 being approximately two per cent of the weight of the fish. 

 The food was prepared fresh each morning, weighed, and 

 placed in the troughs in the usual manner. The food chopper 

 was washed thoroughly after each lot of food was prepared 

 to prevent mixing of foods at the time of preparation. In all 

 other respects the fish were treated in a manner similar to all 

 hatchery fish. The dead fish were removed each day and the 

 losses properly recorded. Each morning unconsumed particles 

 of food and other refuse were removed from the troughs, and 

 every second morning the troughs were thoroughly cleaned in 

 the usual manner. 



It should be noted that the brown trout used were culls, 



