and stirred thoroughly by dragging a loose coil of chicken-mre back 

 and forth along the bottom. When the water has risen within 2 inches 

 of the top of the splash boards, the remaining chlorine concentrate is 

 emptied into the section. The solution is again stirred with chicken- 

 vare. The same general procedure is continued until the entire raceway 

 system, including all springs, is completely filled with vj-ater containing 

 chlorine, Tlie operation of a small outboard motor in a raceway is 

 helpful in circulating the chlorine solution. 



O'Donnell (19A4-) also gave detailed instructions for treating the 

 inside of hatchery buildings, and the reader should consult his paper 

 for these instructions. All loose equipment should be brought out of 

 storage and scriibbed thoroughly with warm water and soap, if possible, 

 and left near a race^vay for chemical disinfection later. Such equipment 

 includes buckets, pans, small troughs, tubs, end screens, seines, extra 

 splashboards, and many others. During this operation much vrarn-out 

 equipment may be found and destroyed. Hatching and rearing troughs 

 should be scrubbed clean. The side walls of all raceways should be 

 scrubbed and the bottoms raked. Particular attention should be given to 

 ar^y left-over fish food, pond sciim, or any other substance of similar 

 nature. 



It is also stressed by this author that after the hatchery is 

 completely disinfected and disease-free, the prevention of recontamination 

 is of prime importance. The movement of any live fish into the hatchery 

 should be absolutely forbidden and production should be started with 

 disinfected eggs. All eggs which are received should be disinfected 

 immediately'- (see below). The hatchery must be protected from the water 

 and packing cases of shipped eggs, the hands of handlers of such eggs, 

 and from the shipping truck. Workers' hapds should be cleaned with 

 soap at intervals. All trucks and equipment coming into the hatchery 

 should be disinfected on the road before entering the hatchery. Drivers 

 should not be allovfed to assist in loading or even to visit ar^r part of 

 the hatchery. 



Handling of Errs 



Since the Furunculosis Committee (1930) isolated Bacterium 

 salmonicida from the ovaries of infected trout, it has been obvious that 

 eggs may serve as carriers of this organism from the infected brood 

 stock to freshly hatched fr^^. Fortunately, B. salmonicida has been 

 found only on the surface of healthy eggs (Smith 1939), while the contents 

 of normal trout eggs vfere found to be free from infection (Williamson 

 1929, Furunculosis Committee 1930). Ova may be contaminated before 

 extrusion, if the female parent is infected, or afterwards by contact with 

 contaminatGd implements, water or hands of workers who have been dealing 

 ■with infected fish (Blake 1930), 



The surface disinfection of fish eggs is only practicable mth a 

 disinfectant which is non-toxLc to the eggs in a concentration permitting 

 a fairly rapid destruction of B. salmonicida or other pathogenic bacteria 



60 



