34 The Food of Fishes. 



difference in color is probably due partly to the smaller 

 amount of light to which those inhabiting the deeper wa- 

 ters of the lake are exposed, and partly to their pisciv- 

 orous habit combined with the comparatively few lurking- 

 places afforded them. There is some evidence that fish 

 food bleaches a fish directly, and a good deal that it does 

 so indirectly, by increasing the importance of an incon- 

 spicuous appearance. 



Stizostethium canadense. Smith. Gray Pike-Perch. Sau- 



GER. ' ' JaCK-S ALMON. ' ' 



Fourteen specimens of this excellent fish were examined, 

 all of which were from the Illinois R., ten taken in Octo- 

 ber, 1878, one in June, 1877, and three in November, 1877. 

 It is evidently a very destructive species. These speci- 

 mens had eaten nothing but fishes. In three cases these 

 were unrecognizable, and in two others I could only tell 

 that they were Acanthopteri. Four of the remaining 

 "pike " had eaten hickory-shad {Borysoma cepedianuni,,) 

 two had eaten catfish (Siluridae) of which one was an Am- 

 iurus, two had eaten sheepshead {Haploidonotus grun' 

 niens), and one had taken a black bass and some sunfish 

 (Centrarchidae). The presence in the stomach of one of 

 these fishes, of a catfish of medium size, with its poisonous 

 pectoral and dorsal spines unbroken, was a striking illus- 

 tration of the gastric energy of this species. 



Stizostethium vitreum, Mitch. Pike-Perch. Wall-eyed 

 Pike. " Salmon." 



This is far the finest of our river fishes, — second to no 

 fresh-water species except, possibly, some of the salmon 

 family. It occurs in the great lakes, and throughout the 

 state generally in the larger streams. It is a much larger 

 fish than the preceding, not infrequently reaching a weight 

 of twenty pounds. Certainly no fish of our waters is bet- 

 ter deserving of attention than this. The only drawback to 

 its increase is in its voracity ; but, although it devours an 

 immense number of other fishes, there is no evidence that 

 it is wantonly destructive or that it eats more in propor- 

 tion to its weight than the black bass. 



