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Becker, George C. / Fishes of Wisconsin
(1983)

Perch family - percidae,   pp. 869-954 PDF (42.5 MB)


Page 870

870   Perch Family-Percidae 
fins well forward and almost beneath the pectoral fins (thoracic posi- 
tion). All have one spine and five rays in the pelvic fins. The two dorsal
fins are separate, the first dorsal with 6-15 spines and the second with
only soft rays. The anal fin is small, with one or two spines, and the 
caudal fin is shallowly forked to rounded. The preopercle is smooth or 
serrate on its posterior edge, and the opercle usually ends in a single flat
spine. The swim bladder is present in Stizostedion and Perca, but it is 
reduced or absent in Percina, Ammocrypta, and Etheostoma. If the swim 
bladder is present, it is without a duct to the pharynx (physoclistous 
condition). 
  Breeding tubercles are now known for 48 percid species. They function 
primarily in maintaining contact between the male and the female during 
the spawning act (Collette 1965). Walleyes, saugers, and perch lack these
structures, and usually spawn in more slowly moving waters; they gen- 
erally display little external sexual dimorphism. Males of most species of
darters are much more brightly colored than females, especially during 
the spawning season. 
  The percids are limited in their range by high summer temperatures. 
They are adapted to temperature climates of the northern hemisphere, 
where water temperatures are less than 4°C (39°F) for more than 8
months of the year in the northernmost parts of their range, and may 
reach about 32°C (90'F) in the southernmost extremities of their native
range (Collette et al. 1977). 
  The walleye, sauger, and perch are among the most valuable sport and 
commercial fishes in Wisconsin. As food fishes, these species rank 
among the favorites and command high prices. 
  The darters are considered important links in the food chains of fishes.
Darters are also among the most beautiful of our native fishes; their 
colors are striking, and they make interesting aquarium pets, although 
some species are hard to keep alive. 
  The darters appear to be particularly sensitive to changes in their 
aquatic environments. Some react negatively to impoundments, since 
they need swift-running water over silt-free bottoms. In areas of heavy 
human settlement, most species of darters are quickly lost. 


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