FAMILY CENTRARCHIDAE 227 



may be due partly to the low temperature of the water. Bass and 

 various sunfishes kept in aquaria at the University of Minnesota also 

 feed much less in winter when the temperature is lowered. 



Sunfishes are the most widespread and abundant members of this 

 family in the northern states. Five species of sunfishes are found more 

 or less commonly in Minnesota: the bluegill, the pumpkinseed or com- 

 mon sunfish, the green sunfish, the longear sunfish, and the red or 

 orange spotted sunfish. Numerous cases of hybridization between these 

 species have been reported. They hybridize extensively in many Min- 

 nesota lakes. Often specimens that show characters of two species and 

 lack the complete characters of either are found. All sunfishes are more 

 or less brightly colored, and the males are especially so during the 

 spawning season. 



Key to Common Species of Family CENTRARCHIDAE 



1 . Dorsal fin about equal to anal in length 2 



Dorsal fin much longer than the anal 3 



2. Length of dorsal fin much less than distance from origin of dorsal fin to 



eye: dorsal spines usually but not always 6 



White Crappie, Pomoxis annularis Rafinesque 



Length of dorsal fin about equal to distance from origin of dorsal fin to 



eye; dorsal spines usually 7 or 8 



Black Crappie, Pomoxis nigro-maculattis (LeSueur) 



3. Scales large, 53 or fewer in lateral line; body short and deep, its depth 

 usually more than two-fifths the length; dorsal fin not deeply notched 

 between the spinous and soft-rayed portions; usually with a black spot 



on flap of the opercle 4 



Scales small, 58 or more in lateral line; body rather long, the depth in the 

 adult one-third the length; dorsal fin more or less deeply notched 10 



4. Anal spines usually 6 Rock Bass, Ambloplites rupestris (Rafinesque) 



Anal spines usually 3 5 



5. Teeth present on tongue 



Warmouth, Chaenobryttus coronariu^ (Bartram) 



Teeth absent from tongue 6 



6. Pectoral fins short and rounded, about one-fourth standard length 7 



Pectoral fins long and pointed, about one-third standard length 8 



7. More than 44 scales in lateral line; gill-rakers long and slender; body stout 



Green Sunfish, Lepomis cyaneUns Rafinesque 



Less than 40 scales in lateral line; gill-rakers short and knoblike; body 

 deep Longear Sunfish, Lepomis megalotis (Rafinesque) 



8. GiU-rakers short and knt)blike; oj>ercular bone stiff behind 



Pumpkinseed, Lepomis gibbosity (Linnaeus) 



GiU-rakers long and slender; opercular bone flexible behind 9 



9. Soft anal rays usually 10 to 12; distinct black blotch near base of last 



dorsal rays; size usually large 



Bluegill, Lepomis macrochirus Rafinesque 



Soft anal rays usually 7 to 9; no single black blotch near base of last 

 dorsal rays; size small Orangespot Sunfish, Lepomis humilis (Girard) 



