were ten days in July and seven in August when it exceeded 71° 

 and on three days it was above 80° F. 



In April, 1921, the pond was drained and the fish counted. The 

 results of the experiment appear in the following table : 



Experiment With Various Species of Fish in Warm-Water Pond 



Put in, June, 1920 



200 bullheads 1 inch long. 

 8 goldfish breeders. 

 75 brook trout Y^k inches long. 

 75 brown trout V-f-i inches long. 

 75 steelhead trout 11/2 inches long. 



Taken out, April, 1921. 



1.50 bullheads 3 inches long. 

 78 goldfish over .3 inches long. 

 47 brook trout 3 to 6 inches long. 

 37 brown trout 2 to 6 inches long. 

 ,52 steelhead 2 to 7 inches long. 



It will be noted that the bullheads grew at a normal rate and the 

 mortality of 25 per cent was not unusually high. The great loss in 

 goldfish was no doubt due to the appetites of the trout. Although 

 there was great individual variation in the size of the trout, it was 

 no greater than has been observed in the hatchery where grading is 

 not resorted to. This variation is a perfectly natural and common 

 phenomenon among trout. Many of the trout were fully as large 

 as those of the same age occurring in our best streams. 



The point which it is desired to bring out, is that here was a pond 

 with mud bottom in which both warm and cold-water fish lived and 

 grew normally. The temperatures up to 81.5° F., were not too 

 high nor of long enough duration to kill the brook trout. The lower 

 temperatures down to 69° were not so prolonged as to materially 

 retard the growth of the bullheads. The conditions were thus suit- 

 able for the trout as well as the bullheads and it would seem to in- 

 dicate that so far as the temperature factor is concerned, trout may 

 be produced in ponds in which the water is much warmer than has 

 heretofore been thought possible. 



In the streams in the vicinity of Ithaca, New York, the highest 

 temperature in which brook trout were actually found in numbers 

 was 81° F. (Van Pelt Brook, August 6 and 7, 1918.) In other 

 parts of this stream 83° was frequently noted but not in any case 

 where brook trout were actually present. This brook, however, is 

 considered an excellent though small brook trout stream and the 

 catches from year to year fully bear out this belief. In other brooks 

 equally good for brook trout fishing, temperatures of 11° to 79° F., 

 were frequently recorded in places where brook trout were observed 

 in abundance. There are more than twenty-five streams in Tompkins 

 County, New York, now containing brook trout, and it is an ex- 

 ception indeed to find one whose highest summer temperature does 



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