258 



FISH HATCHERY MANAGEMENT 



Table 33. recommended sizes for dry formulated feeds given to trout. 



GRANULE OR 



PELLET 



size" 



Starter granule 

 No. 1 granule 

 No. 2 granule 

 No. 3 granule 

 No. 4 granule 



— " pellets 



_L" 



16 



pellets 



'^Feed sizes — US Fish and Wildlife Service Trout Feed Contract Specifications, Spearfish 

 Fisheries Center, Spearfish, South Dakota 57783. 



particles are too small, the feed dissolves in water and is lost. It is impor- 

 tant for maximum feed efficiency to provide an acceptable range of feed 

 sizes for fish during their different growth stages. 



Granules or crumbles are made in a range of sizes for fingerlings of dif- 

 ferent weights (Tables 33-35). Hard pellets are cracked into granules and 

 the different particle sizes are separated by screening. 



When the fish are being shifted from a small granule to a larger size, the 

 change should be gradual rather than abrupt. The change may be made ei- 

 ther by mixing the two sizes together and feeding them at the same time, 

 or by feeding the two sizes separately, starting with a few feedings of the 

 larger size each day and gradually increasing the frequency until only the 

 larger particle is fed. 



Table 34. recommended sizes for abernathy dry pelleted feed given to 



PACIFIC salmon. (SOURCE: L.G. FOWLER, UNPUBLISHED.) 



GRANULE OR PELLET SIZE 



FISH SIZE (NUMBER PER POUND) 



Starter granule 

 -!--inch granule 



- — inch granule 



^-inch granule 



— inch granule 



—-inch pellet 



32 ^ 



—-inch pellet 

 —-inch pellet 



16 ^ 



800 + 

 800-500 



500-200 



200-100 



100-75 



75-.50 



.50-20 

 Less than 20 



