88 American Fisheries Society 



to introduce new plants every three or four weeks, in order to 

 enable them to grow to the surface to attract the various flies and 

 insects. New plants starting from bottom should be controlled 

 so that the excrement from the fish will not lodge and foul the 

 ponds. Keeping them in clusters prevents fouling, as men can 

 work. around them from the top of the walls with long-handled 

 brushes. 



We then place in the pools according to the number of the fish, 

 one or two galvanized iron boxes, 18 inch sq., 24 gauge, open at the 

 bottom, with a one-inch iron band around the bottom. Holes are 

 drilled through the band for 5-16 inch iron rods, used to hold a 

 wood frame containing trays for fly-blown meat. A small pin 

 hole is punched through the top to permit the gas to escape, in 

 order not to kill maggots. The bottom of this box is submerged 

 one inch in the water to do away with objectionable odors. Any 

 stale or tainted meat will do. The big blue flies produce the 

 largest maggots. Care will have to be taken to keep beetles 

 away from the meat or they will destroy the fly maggots as fast 

 as they hatch. 



Also we thoroughly roil ponds twice a week. One half yard of 

 field loam to twenty ponds is sufficient. 



Tables. 



It will be noted by the table that the losses of brook trout for 

 the month of July is 16.5%, brown trout fingerlings 61.4%, brown 

 trout yearlings 6.7%, rainbow trout fingerlings 1.3%, rainbow 

 trout yearlings 7.3%. Loss of all kinds 18.9%. 



August losses — Brook trout fingerlings 1.7%, brown trout 

 fingerlings 1.9%, brown trout yearlings 4%, rainbow trout finger- 

 lings 99-100 of 1%, of rainbow trout yearlings 5.6%. Loss of all 

 kinds 2.2%. 



September losses — Brook trout fingerlings 1.2%, brown trout 

 fingerlings 3-50 of 1%, brown trout yearlings 1.4%, rainbow trout 

 fingerlings 1-50 of 1%, rainbow trout yearlings 1.3%. Loss of 

 all kinds 1-20 of 1%. 



The above losses occur in spring water at 52 to 62 degrees. 

 The same fish were used for the entire period. 



