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Becker, George C. / Fishes of Wisconsin

Keys to the fishes of Wisconsin,   pp. 63-170 PDF (22.5 MB)

Page 63

Keys to the Fishes of Wisconsin 
Structure and Use of the Keys 
  Taxonomic keys are artificial devices. Species did not evolve from keys;
keys are man-made constructions designed to help in the identification of
ferent species or forms. 
  The keys in this book are dichotomous; that is, the characteristics are
in pairs or couplets of contrasting statements. The user of the key chooses
statement which applies to the fish being identified, and then proceeds to
next couplet indicated. As inapplicable statements are progressively elimi-
nated, it will eventually be possible to give the correct species label to
the speci- 
  The first of the keys that follow is the Key to the Families. Ten species
Wisconsin are the sole representatives of their families in the state. For
fishes, the family name is given, and a reference to the page in the book
the main species account is found. The families for which this occurs are
following: Paddlefishes, Bowfins, Freshwater Eels, Smelts, Mudminnows, Pi-
rate Perches, Trout-perches, Codfishes, Silversides, and Drums. As an example,
if the specimen keys out at 12a (PIRATE PERCHES, Aphredoderidae), the user
of the key is referred directly to the pirate perch account on page 733 in
main text. 
  All other families of Wisconsin fishes are represented in the state by
than one species. For fishes in these 16 families, the family name is given,
a reference to a separate key to that family. These keys follow the Key to
Families. For instance, if the fish that is being keyed out is a minnow,
the user 
of the key will be directed at 21a in the Key to the Families to a separate
Key to the Minnows and Carps (page 107). In this key the 45 known species
Wisconsin minnows and carps are separated out and identified to species,
after careful searching it should be possible to arrive at the common and
tific names for the minnow specimen and the page number for that species

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