Figure 16. — Weigliinii' a sample 

 weight of all tish in rh ejxi 



)f a known nnml 

 (1 ti) ascertain qi 



»f salmon finger 

 rities of food to 



gs to determine 

 fed daily. 



Modified feeding charts have been 

 prepared for the various species of 

 sahnon. 



To use feeding charts it is neces- 

 sary lo know the weight of the fish 

 in each ])on(L By weigliing repre- 

 sentative samples of fish at intervals 

 and knowing the numbers of fish in 

 the pond, tlie weight of all fish can 

 be calculated. At large hatcheries, 

 where it would be impractical to 

 weigli numbers of fish in each pond 

 at semi weekly inter\als to de- 

 termine amounts of foods to ()e fed. 

 the Fi.-h and Wildlife Service has 



developed the use of pilot lots of 

 fish. These lots are held in small 

 laidvs and are weighed to indicate, 

 with the application of factors to 

 compensate for differing conditions, 

 tlie weights of the fish in the many 

 large i)()nds (Palmer et ah. f^rtii). 

 The daily offering of food to the 

 lish is from 10 |)ercent to .") percent 

 of the total weight of the fish — 

 the smaller iisli receiving the greater 

 pei-centages. 



A variety of methods ha\e been 

 employed to disti'ibute the food to 

 lish. 'I"lu' problem is one of [)re- 



36 



