90 Conservation Department 



on the one hand to those on the other. Within each group there 

 are degrees of adaptations. For example brook trout are better 

 adapted to very low temperatures than are brown and rainbow 

 trout. At the fish hatchery at Bath, New York, where the water 

 is very cold, young brook trout grow much faster than do the young 

 of the other two species. 



In the Oswego watershed there are streams ranging from a 

 summer maximum temperature of less than 50 degrees Fahr. to a 

 summer maximum of more than 85 degrees Fahr. 



The coldest streams were found to be limited to two species of 

 fish, the brook trout and the sculpin (Cottus cognatus). These 

 fish were found in the headwaters of Lake Como inlet in water 

 as cold as 45 degrees Fahr. 



Generally, the warmer the stream, the more species of fish 

 present. This is illustrated in the case of a stream such as Fall 

 creek. Certain very cold headwaters near McLean, New York, 

 contain only brook trout and sculpins (Cottus coqnatus). As the 

 water gradually warms, more species appear and throughout the 

 shaded area of Beaver brook (a large tributary of Fall creek) 

 black-nosed dace, horned dace, common suckers, and common 

 shiners begin to appear along with the trout and sculpins. At the 

 point where Beaver brook joins Fall creek the water, being ex- 

 posed to the sun, has become too warm for trout and sculpins, but 

 the minnows and suckers are very common. Below this point the 

 small-mouthed black bass and pickerel are added to the fish fauna, 

 the bass at least becoming more common downstream, where the 

 water warms considerably. Unfortunately the maximum tem- 

 peratures of this stream at various points have not been obtained. 



The warmest streams contained very many species of fish but 

 were entirely avoided by the trouts, the sculpin (Cottus cognatus) 

 and perhaps by certain minnows (Margariscus and Clinostomus) . 

 The abundant fish fauna of a stream of this type is illustrated 

 by Ganargua creek (Mud creek) near Fairville, a shallow wide 

 stream which doubtless reaches a very high summer temperature. 

 Here 15 species of fish were collected : small-mouthed black bass, 

 rock bass, zebra darter, tesselated darter, fan-tailed darter, black- 

 sided darter, green-sided darter, common shiner (Notropis cornutus 

 chrysocephalus) , satin fin minnow, spot-tailed minnow, blunt- 

 nosed minnow, northern pike, stonecat (Noturus), common sucker, 

 red-fin sucker (M. anisurum). Yellow pike (pike-perch) are also 

 known to be present here. It may be mentioned that not all 

 warm water streams have as many species as this one. The fauna 

 is, however, rather a typical one for the warm streams of the north- 

 ern part of the drainage. 



Trout Stream Associations. — The temperature of approxi- 

 mately 70 degrees Fahr. is considered as the dividing point be- 

 tween "cold" and "warm" waters in regard to stocking streams 

 with trout. Fishes which were found associated with brook, brown 

 or rainbow trout in streams of the Oswego watershed are as fol- 

 lows : Black-nosed dace, horned dace, common shiner (Notropis 



