To economically utilize hatchery space and 

 to increase capacities, a system of culturing 

 trout eggs in three-gallon jars has been intro- 

 duced. This method of hatching trout is es- 

 pecially desirable at those stations with large 

 numbers of raceways. Young trout fry can 

 be cared for in the jars until they are liberated 

 into rearing ponds. 



New fiber-glass hatchery troughs were de- 

 signed and constructed to replace the old red- 

 wood troughs that had been in use over the 

 past quarter-century. The new troughs have 

 paint pigment imbedded in the fiber-glass, thus 

 lessening continual maintenance. The new 

 troughs are easier to keep clean and sanitary. 



There are two sources of fish eggs; wild 

 stock, or spawn gathered from fish reared 

 under natural conditions in lakes; and domestic 

 stock, or spawn taken from adult fish retained 

 at the hatchery. Often fish produced from 

 wild stock are more difficult to rear in the 

 hatchery, are more susceptible to disease, and 

 grow more slowly. A constant supply of eggs 

 from wild stock cannot always be assured, and 

 often there is adverse public sentiment and 

 conflict where spawning stations are located. 

 There are situations where wild stock is de- 

 sirable, and at present, spawning stations for 

 wild rainbow trout are maintained at Lake 

 Mary Ronan, Bitterroot Lake, and Willow 



Creek Reservoir; wild cutthroat trout eggs are 

 obtained from Ashley Lake and Georgetown 

 Lake; and wild grayling eggs from Rogers 

 Lake and Agnes Lake. Eggs are obtained from 

 kokanee seined from Flathead Lake, and wall- 

 eye and northern pike eggs are obtained from 

 fish in Nelson Reservoir. 



Domestic brood stock is maintained at 

 hatcheries to produce fish that have been im- 

 proved through selective breeding. Such fish 

 grow faster, have early sexual maturity, in- 

 creased individual egg production, and resist- 

 ance to disease. That this program is possible 

 is clearly demonstrated at the Arlee Hatchery 

 where a selective breeding program with hatch- 

 ery brood stock has been carried out over the 

 past several years. At Arlee and Hamilton 

 fall-spawning rainbow trout, California gold- 

 en trout, and west-slope cutthroat trout are 

 being developed as hatchery brood stock. Plans 

 are presently being formulated to expand this 

 program to include spring-spawning rainbow 

 trout and Yellowstone cutthroat trout, thereby 

 making the hatchery system less dependent on 

 outside egg sources. With the hatchery brood 

 stock program established there will be a con- 

 stant supply of eggs available from pure strains 

 of fish that can be identified by tagging or 

 marking, and adverse public sentiment to wild 

 stock spawn-taking stations will be reduced. 



EGG PRODUCTION 



January 1 - 

 December 31, 1958 



Rainbow 7,004,112 



Cutthroat - 4,139,292 



Grayling 743,892 



Kokanee 8,126,774 



Walleye Pike ...... 1,320,000 



Northern Pike .... 832,700 



TOTALS 22,166,770 



9,818,111 

 3,501,568 

 1,241,453 

 4,643,104 

 1,410,000 

 590,000 

 21.204,236 



35 



