228 NORTHERN FISHES 



10. Maxillary bone in the adult not extending beyond the posterior margin 

 of the eye; mouth of medium size; scales about 11-74-17, 15-18 rows of 



scales on cheek Smallmouth Bass, Micropteriis dolomieu Lacepede 



Maxillary bone in the adult extending beyond the posterior margin of the 

 eye; mouth large; scales about 7-68-16, 10 or 11 rows of scales on cheek; 

 young with a black stripe along side, which becomes somewhat indistinct 

 in large adults Largemouth Bass, Huro salmoides (Lacepede) 



Note: The five sunfishes described are known to hybridize with one another, so that 

 many a sunfish caught in nature represents a hybrid. This key is based on pure- 

 type characters and does not attempt to separate these hybrids. 



GENUS Micropteriis Lacepede 



This genus includes four species (Hubbs and Bailey, 1940, 1944) , 

 only one of which is found in the latitude of Minnesota. The other three, 

 including the spotted or Kentucky bass, Micropterus punctulatus 

 (Rafinesque) , are southern. 



NORTHERN SMALLMOUTH BASS (River Bass) 

 Micropterus dolomieu dolomieu Lacepede 



In the northern smallmouth bass (Figure 4lB) the mouth is of 

 moderate size, the maxillary not extending beyond the eye. The young 

 are more or less barred or spotted and never have a black lateral band. 

 In the young the caudal fin has a yellow or orange base, black center, 

 and a white tip. The very young fry are jet black. The color of the 

 adult varies above from a dark green flecked with gold to a pale olive 

 brown; it is white below. The body is sometimes a uniform color, but 

 often it is mottled with vermiculations of a darker olive green. This 

 mottling is most often noted just after a smallmouth bass has been 

 landed after putting up a brave fight. The eyes are more or less reddish. 

 There are 15 to 18 rows of scales on the cheeks and 11 to 14 longitudi- 

 nal series between the middorsal and the lateral line. The dorsal fin 

 has 9 or 10 spines and 13 to 15 soft rays; the spinous portion is low. 

 The anal fin has 3 spines, rarely 4 or 2, and 10 to 12 soft rays. The 

 lateral line has 66 to 78 scales. The pyloric caeca on the intestine 

 where it leaves the stomach are single, but are branched at their base 

 in the largemouth. This species commonly reaches a length of 1 to 2 

 feet. Weights run up to about 7 pounds, though smallmouth bass 

 weighing over 4 pounds are seldom caught. 



It seems rather odd that in certain Minnesota lakes it is difficult to 

 distinguish the adult smallmouth bass from the largemouth, though 

 the young of the two species, until they are yearlings at least, are so 

 radically different that they can be distinguished at a glance. Hybrids 

 have never been reported. 



The northern smallmouth bass ranges from the Lake of the Woods 

 region to Quebec and southward to northern Alabama and eastern 



