Family PERCIDAE 



THE PERCH FAMILY 



The perch family inchides the perch, the walleye, the sauger. and 

 numerous species of darters. The body is more or less elongated or 

 elliptical. The lateral line is complete. The mouth may be either terminal 

 or inferior. Teeth are present on the jaws and usually on the vomer and 

 palatines; sharp pharyngeal teeth are present. The opercle ends in a 

 flat spine. Seven branchiostegals are present. The gill-membranes are 

 free from the isthmus; a slit occurs behind the fourth gill-arch; the 

 gill-rakers are slender and toothed. The dorsal fin is completely divided, 

 the anterior usually containing about 13 spines. The anal fin has 1 or 2 

 spines. The ventral fins are thoracic, with 1 spine and 5 soft rays. The 

 larger species found in Minnesota consist of the common perch, the 

 walleye, and the sauger. The darters, belonging to the subfamily 

 Etheostominae, are all small and rather difficult to study. Members 

 of the family Percidae occur in Europe, Asia, and North America. 



Key to Common Species of Family PERCIDAE* 



1. Six branchiostegal rays, tail not forked or weakly forked, pseudobranchiae 



rudimentary or lacking, small size 4 



Seven or rarely eight branchiostegal rays, tails forked, pseudobranchiae 

 well developed, large size (except stunted perch) 2 



2. Canine teeth (imusually long teeth) present on the jaws and palatine 



bones 3 



No canine teeth present, bars on sides 



Yellow Perch, Perca flavescens (Mitchill) 



3. Rays of the soft dorsal fin about 20 (19-22); a large black blotch at the 

 base of the last dorsal spines; no distinct black spot at the base of the 

 pectoral fins; tip of lower lobe of caudal fin usually whitish; pyloric caeca 



usually 3 Walleye, Stizostedion ritreuni vitrcum (Mitchill) 



Rays of soft dorsal fin 17 to 20; no distinct black blotch at the base of the 

 last dorsal spines; a black spot at the base of tlie pectoral fins; tip of lower 



lobe of caudal fin not whitish; pyloric caeca usually 5 to 8 



Eastern Sauger, Stizostedion canadense canadense (Smith) 



4. Body very elongate, pencil-shaped; depth 7.8-9.0 in length; flesh pellucid in 



life; a single anal spine; scales of trunk confined to median sides 



Western Sand Darter, Amvwcryjiia clara (Jordan and Meek) 



Body less extremely elongate; depth 5.0-7.0; flesh opaque; 2 anal spines; 

 squamation of body almost or quite complete 5 



5. Premaxillaries fused to preorbitals at the sides and overhung slightly by a 



very gibbous snout; color largely green in life 



Northern Greenside Darter, Etheostoma blennioides blennioides 



(Rafinesque) 



Premaxillaries free from the preorbitals at the sides 6 



'Modified from Hubbs and Lagler (1941) . 



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