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

Wisconsin fishes and fishery management,   pp. 18-37 PDF (8.3 MB)


Page 36

 
36    Wisconsin Fishes and Fishery Management 
southeastern Wisconsin, where it has become successfully established, particu-
larly in urban areas. The European rudd (Scardinius erythrophthalmus) was
intro- 
duced into Oconomowoc Lake in 1917, and at least temporarily bred success-
fully. No recent records are known (Greene 1935). In the 1970s, Asiatic grass
carp (Ctenopharyngodon idella) were illegally introduced into several private
ponds 
in eastern and southern Wisconsin. The Wisconsin Department of Natural Re-
sources has poisoned out these waters to prevent what may be another "carp
problem." 
  Every year a number of tropical fishes from aquariums are illegally intro-
duced into manmade warm water ponds. Occasionally these produce one or 
more broods during the summer of release. In the early 1960s I seined numer-
ous guppies (Poecilia reticulata) and several unknown tropical fish from
small 
ponds near Allenton (Washington County). Priegel (1967a) reported that a
Tila- 
pia species, a native of Africa, had been placed in Supple Marsh adjacent
to 
Lake Winnebago, and that in August 1965 a 190-mm specimen was caught by 
an angler using worms as bait. Tropical fish are not known to survive Wiscon-
sin's cold winters. 
  Although it is now unlawful to introduce exotic fishes into the waters
of Wis- 
consin, the problem is a continuing one. More than 100 million fish were
im- 
ported into the United States in 1972 alone, and some of these undoubtedly
were released into public waters. The majority pose no danger to native fishes,
but the probability exists that one or more species may become uncontrollable
pests. 
Extirpated and Endangered Fishes 
Each species of fish has its evolutionary lifetime: infancy when it is newly
evolved 
from pre-existing forms; maturity, when it is expanding its range and becoming
a part of the ecosystem; old age, when its numbers and range decrease; and
ultimately death. Some species are like weeds. They are everywhere and suc-
cessfully compete for space and food. Other species hang onto their identities
by slim threads. They are vulnerable to fishing, to predators, and to slight
changes in the environment. 
  The official Wisconsin Department of Natural Resources listings of fishes
placed 
on endangered, threatened, and watch status are given in Wisconsin Depart-
ment of Natural Resources Endangered Species Committee (1975) and Les (1979).
I use these official listings for each troubled species in that part of the
species 
account entitled "Distribution, Status, and Habitat." The following
paragraphs 
give my personal listings of endangered species, which differ somewhat from
those of the Wisconsin Department of Natural Resources, although they are
based on the Department's definitions of endangered fish categories. 
  Extirpated Wisconsin species are the skipjack herring, blackfin cisco,
deep- 
water cisco, longjaw cisco, shortnose cisco, ghost shiner, ironcolor shiner,
creek 
chubsucker, and black redhorse. All were still present in Wisconsin waters
in 
the late 1920s. 
  Endangered fishes are those in trouble. Their continued existence as a
part of 
the state's wild fauna is in jeopardy, and without help they may become extir-
pated. They are officially protected by Wisconsin law (Chap. 29.415, Wis.
Stat- 


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