he is led to think that they can live in the higher temperatures he will 

 want to stock with trout all of the streams where the water has hecome 

 much warmer as the result of deforestation and the natural progress of 

 civilization. Dr. Embody's experiments are very interesting, but I ques- 

 tion whether they are practicable in hatchery work where a man is rais- 

 ing trout for a living or to produce large results. If the troughs in which 

 he conducted experiments with a limited number of fish had been as 

 crowded as the troughs at our hatcheries, the mortality would have 

 appeared at a lower temperature. 



Dr. G. C. Embody, Ithaca, N. Y. : The fact seems to be that we mis- 

 judge our streams. If only those streams in Tompkins County, New York, 

 that did not exceed 70° F., were stocked with brook trout, there would not 

 be more than two in the whole county. But on three consecutive days I 

 found several brook trout there in perfect contentment with a temperature 

 of 81° lasting for about five hours. Judging from experiments in the 

 trough, 83° would be the maximum temperature at which trout could live 

 perhaps for a few hours. Brook trout will live all summer in a water 

 temperature of 70°. I would not have a bit of hesitation about going into 

 trout culture where the water is not warmer than 74° on the hottest days. 

 I would not expect to raise the average number of trout the first five or 

 six years, but I would expect eventually to have a strain which would come 

 through in a perfectly normal manner. But in a wild stream It is altogether 

 different, because there you have not introduced conditions of domestica- 

 tion. Rainbow trout seem to resist the high temperature better than brown 

 and brook trout. The last named would succumb first. I found the rain- 

 bows in higher temperatures than the browns. 



Mr. Titcomb: As to propagating trout in a hatchery with a tempera- 

 ture of 74° or 70° for a month at a sti*etch, it is a proposition that I do not 

 want to invest any money in, and I would not want the tax payers to invest 

 any money in it. 



Mr. G. C. Leach, Washington, D. C. : At Manchester, Iowa, a spring 

 stream meanders through the meadows for quite a distance where it warms 

 up in summer from 48° to 65° F. before reaching the hatchery grounds. 

 We take brook trout out of the ponds and put them in the stream where 

 they live under more or less natural conditions. During the heat of the day 

 they congregate in pools probably five or six feet in depth, and where there 

 is a strong current. The volume of water is probably 800 to 1,000 gallons 

 a minute. I seriously doubt if we would be able to hold these trout in 

 the stream successfully with a volume as small as 150 or 200 gallons per 

 minute. We got from 85 to 90 i)er cent fertilization from the trout eggs 

 obtained from the creek as against 50 per cent from trout held in the 

 ponds at 50°. I think our success was due to the fact that the stream has 

 a rocky bottom, deep pools, and a very large volume of water. To a certain 

 extent we were raising wild trout. We shipped rainbow trout to Louisiana 

 to ascertain if they would live in certain streams. The water temperature 

 there was about 65°, and some of the fish were reported eight or ten inches 

 in length the first year, but they never reproduced. 



Mr. Titcomb: The higher the temperature in which you can success- 

 fully rear trout the more rapidly they will grow. In some hatcheries you 

 can carry trout intensively in troughs with a temperature of 50° to 55°. 

 At other hatcheries the water is such that you can carry them intensively at 



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