American Fisheries Society 121 



A dam reaching about an inch above the surface is put into 

 each trough near its head, forming a small pool into which 

 falls the water from the inlet. This dam keeps the fry from 

 getting- under the inlet, where they might be injured by the 

 force of the falling water, and also serves to distribute the 

 flow across the width of the trough. A partition screen is 

 put midway in the trough, giving two compartments each 

 containing 6,000 fry. 



The troughs remain unbrushed from the time the eggs are 

 laid out to hatch until the sac is gone, dead eggs being picked 

 out dail)' with tongs, and dead fry with a small fan, by 

 which they can be lifted without touching the others. The 

 fan is made of small wire ])ent near its middle to form a 

 scjuare about l\-> inches on a side and having threads tied 

 across to form a net, the rest of the wire being twisted to- 

 gether to receive a handle. 



As the water grows warm and slime appears the practice 

 of "mudding" is begun. The earth employed is a fine sandy 

 loam, which is introduced daily thereafter through the sum- 

 mer by holding a half-pint of the earth in a bowl-stainer 

 under each inlet. The finer particles are washed through 

 the strainer and carried by the current to all parts of the 

 trough. The sand thus introduced keeps the bottom free 

 from slime and is allowed to accumulate. When the sacs are 

 absorbed the fry are siphoned out. Those to be liberated are 

 carried in pails to the lake, and in the same pails or in cans, 

 the water being frequently changed, they are conveyed by 

 boat or canoe to suitable places along the shore, care being 

 exercised to scatter them widely. 



The troughs are now thoroughly cleaned, partition and 

 headscreen removed, and 1,000 young fish are returned to 

 each trough to be fed through the summer. The flow is in- 

 creased to about 10 gallons per minute, and later to 15 gallons 

 as the temperature rises. 



Four feeds per day are offered, consisting of herring roe 

 and beef liver ground together in a meat-chopper, the method 

 being to mix the ground food with water to the consistencv 



