HATCHING TROUT 159 



of wood which forms the dam at the lower end 

 of the trough is removed, first making sure that 

 the screen above the dam is secure and clean. 

 When the water has fallen to about an inch in 

 depth, the operator feathers from one end of 

 the trough to the other. Then he takes the scap- 

 net and, beginning at the upper end, works it 

 gradually to the lower in very short sweeps, 

 picking up the dirt and also very weak fish, 

 which if allowed to remain would undoubtedly 

 die. A spawning-pan containing water is kept 

 close at hand and into it is emptied the contents 

 of the scap-net, to be finally thrown away. 



