276 FISHES OF ILLINOIS 



Spines, wel] separated from the soft rays; scales rather small, ctenoid. 



Fresh waters of northern regions; 3 closely allied species, one each in 

 Europe, Asia, and North America. 



PERCA FLAVESCENS (Mitchill) 

 (yellow perch; ringed perch; American perch) 



Mitchill, 1814, Rep. Fish. X. Y., 18 (Morone). 



G., I, 59; J. & G., 524 (americana) ; M. V., 134; B.. I, 48; J. & E., I, 1023; X., 36; 

 J., 43 (americana); F, F., I. 3, 29 (americana); F., 63 (americana); L., 26. 



Length 1 foot; body only moderately elongate, considerably com- 

 pressed; back elevated, highest in front of spinous dorsal; the profile con- 

 vex from first dorsal spine to occiput, thence straightish or slightly con- 

 cave to muzzle ; depth 3.3 to 3.8; greatest width of body about f of its 

 depth; depth caudal peduncle 2 to 2.2 in its length. Color of sides 

 and back brassy green to golden yellow, with seven broad bars of 

 dusky crossing each side from back nearly to belly ; belly whitish with 

 reflections of green, salmon, and yellow; iris brassy at edge; spinous dor- 

 sal gray, usually with a black spot on last two membranes; soft dorsal 

 and caudal plain green; pectorals transparent grayish green; ventrals 

 and anal variously light grayish green or orange to crimson according to 

 season and habitat. Head 3 to 3.5; width head 1.8 to 2 . 1 in length; 

 interorbital space nearly flat, 3.8 to 4 . 3 ; eye 1 . 1 to 1 . 4 in interorbital, 

 4 . 5 to 5 . 5 in head ; nose 3 . 4 to 3 . 7 , longer than eye ; maxillar}' to middle 

 of orbit, 2 . 4 to 2 . 8 ; opercle ending above in several coarse jagged points; 

 preopercle strongly serrate, especially below; gill-rakers X + 15, the 

 longest more than half length of branchial filaments; pyloric caeca 3. 

 Dorsal XII to XIV-II or III, 12 to 13; longest spine a little more 

 than 2 in head; length base of soft dorsal about f base of spinous; caudal 

 lunate; anal II, 7-8; ventrals more than half-way to vent; pectorals 1 .6 

 to 1.9 in head. Scales 6 or 7, 57-62, 15-18; lateral line nearly or 

 quite complete; cheeks scaled, in about 8 to 10 rows. 



This is one of the best-known fishes in th*e northern part of the 

 state, sw^arming especially along the piers on the lake front at Chi- 

 cago, where it is the common game of the local fishermen. It occurs 

 elsewhere in Illinois mainly in the upland lakes of the northeastern 

 part of the state, in the tributary streams flowing into Lake Michi- 

 gan, and in the Illinois and Mississippi rivers as far south as Mere- 

 dosia. It is virtually unknown in the southeastern half of the state, 

 and has never once been taken by us in any of the streams of the 

 Wabash or Kaskaskia systems, or from any of those farther south. 

 It is inconstant in its abundance in the Illinois River, and is said to 

 have increased greatly there since the opening of the drainage canal 

 has cooled and cleared the waters of that stream. 



