258 American Fisheries Society 



mined by environment, and not particularly restricted to young 

 fish, what is the environmental factor affecting certain aggre- 

 gations of fishes associated, at least part of the year in the same 

 waters, with other aggregations in Lake Erie and Lake On- 

 tario, which latter are at all ages distinguished by color? And 

 does the distinction disappear if removal from one environ- 

 ment to another takes place? These are points which cannot 

 be determined by cursory inspection of a few individuals. 



In connection with a biological survey of the Great Lakes, 

 the U. S. Fish Commission Report for 1902, page 127, states 

 that Dr. Raymond Pearl undertook a demonstration by statis- 

 tical methods of the relations of the blue pike to the yellow 

 pike {Stizostedion vitreum) of the Great Lakes, and that 

 enough was learned to know that the wall-eyed pike is a species 

 of remarkably low variability, and that there are no structural 

 differences between the blue and the yellow varieties, this 

 being in accord with other observation. 



It is not my purpose to discuss the question of nomencla- 

 ture of the pike perch, or so-called wall-eyed pike. But, as 

 concerns the species which Rafinesque called Perca, or Stizo- 

 stedion salmoneum, there is no indication in his description 

 that it is the form recognized in Lake Erie and Lake Ontario 

 as blue pike. It is the common pike perch of the Mississippi 

 Valley which, as Rafinesque stated, occurred all over Ohio, 

 and in the Kentucky, Licking, Wabash, and Miami Rivers, 

 during the spring and summer and was known as salmon, 

 white salmon and Ohio salmon. 



In accordance with the wishes of the United States Com- 

 missioner of Fisheries, I have recently examined a series of 

 each form, for the most part representing Lake Erie and Lake 

 Ontario. In view of the fact that previous discussions have 

 been to the effect that the blue pike were immature fish, I 

 selected a series of 20 specimens of yellow pike which in their 

 maximum lengths would include the lengths of the available 

 blue pike. The yellow pike ranged from 91 mm. (about 



