FISHES OF COLORADO IO3 



small, few exceeding three inches in length and some never reaching the length of 

 one and a half inches. It is to this group that the three species of Percidae native 

 in Colorado are referable. Two species of large Percids, the Wall-eyed Pike and 

 the Yellow Perch, have been introduced into the lakes and reservoirs of eastern 

 Colorado, so that in aU four genera are now represented in the state. 



Key to PERCroAE Represented in Colorado 

 a. Jaws with large canine teeth; size large, length up to three feet; body elongate. 



Stizostedion Rafinesque, p. 103 

 aa. Jaws without canine teeth; size smaller, length under 15 inches. 



b. Soft dorsal fin with II or III spines; depth 3 to 3.5 in the length; preoperculum with a 

 serrate margin; dorsal spines XII to XVI; anal spines II; size large, length of adults 



exceeding 6 inches Perca (Artedi) Linnaeus, p. 104 



bb. Soft dorsal fin without spines; depth 4 to 6 in the length; preoperculum without a heavily 

 serrate margin; dorsal spines VII to XV; anal spines I or II; adults always less than 6 

 inches in length. 



c. Anal spines II; premaxillaries not protractile . Elkeosloma Rafinesque, p. 107 

 cc. Anal spine I ; premaxillaries protractile Boleosoma DeKay, p. no 



Subfamily Luciopercinae 

 Genus STIZOSTEDION Rafinesque 

 The American Pike Perches 

 Stizostedion Rafinesque, Ichthyologia Ohiensis, p. 23, 1820. 



Body elongate, size large; jaws with large canine teeth; premaxillaries 

 protractile; scales small and strongly ctenoid. 



This genus includes two large carnivorous perches, native in the upper 

 Mississippi drainage, one species of which has been introduced into a few of the 

 lakes of eastern Colorado. 



Stizostedion vitreum (Mitchill) 

 Wall-eyed Pike 



Perca vilrea Mitchill, Supp. Amer. Month. Mag., Vol. II, p. 247, 1818 (Cayuga Lake, New 

 York). 



Body elongate and somewhat compressed; depth 4.25 to 5 in the length to 

 the base of the caudal fin; head large and long, about 3. S in the length of the 

 body; eye large and prominent, its diameter 4. 75 to 6 in the length of the head; 

 center of the eye nearer to the tip of the snout than to the posterior margin of the 

 operculum; mouth large, angle of the mouth reaching the level of the center of 

 the eye, lower jaw shghtly longer than the upper; both jaws with large canine 

 teeth; spinous dorsal separated from the soft dorsal by a distance equalling the 

 diameter of the eye, longest spine of the spinous dorsal exceeding in length the 

 longest ray of the soft dorsal, base of the first spine of the dorsal on a level with 

 the spine of the ventral, base of the first ray of the soft dorsal on a level with the 



