THE RELATIONSHIP OF THE SO-CALLED BLUE 



PIKE AND YELLOW PIKE OF LAKE 



ERIE AND LAKE ONTARIO 



By Dr. William Converse Kendall 



Scientific Assistant, U. S. Bureau of Fisheries 



Washington, D. C. 



The relationship of the pike perches, locally designated as 

 blue pike and yellow pike, has been more or less a moot ques- 

 tion, and the status of their idenity has, from time to time, 

 given rise to investigation of the subject. Each inquiry, how- 

 ever, has resulted in the conclusion that there was no distin- 

 guishable difference. 



In connection with the name given by Rafinesque to the 

 Mississippi Valley fish, Jordan and Evermann say : 



The name salmoneum has been applied to the so-called "blue pike" 

 originally described from the Ohio river, but more common in the Great 

 Lakes, particularly Ontario and Erie. It is smaller and deeper in body 

 than the ordinary vitreum and different in color, but it is not likely 

 that any permanent distinctions exist, this species, as usual among 

 freshwater fishes, varying largely with the environment and with age.* 



The fact referred to by Jordan and Evermann, that it is 

 usual for freshwater fishes to vary largely with environment 

 and age, is without significance in a study of the relation- 

 ships of fishes unless the way in which they vary and the 

 cause of variation are considered. Their statement implies 

 that distinctions to be of taxonomic value must be permanent. 

 Conversely, if a distinction is permanent it is of specific value. 



So far as the blue pike concerns the fishermen and fish 

 dealers, there is a permanent distinction, that of color. The 

 question, then, is how permanent this distinction is. Is it 

 restricted to young fish and is it therefore, a distinction that 

 disappears with age and maturity? If it is a distinction deter- 



* Jordan and Evermann. Fishes of North and Middle America. Bull. 47, U. S. 

 National Museum, vol. 1, p. 1021. Washington, 1896. 



