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Fago, Don / Distribution and relative abundance of fishes in Wisconsin: I. Greater Rock River basin
(1982)

Results and discussion,   pp. 9-22 PDF (7.0 MB)


Page 9


RESULTS AND DISCUSSION
   Findings are presented first for the
individual basins, then for the entire
Greater Rock River basin, and finally
for some of the more interesting spe-
cies including those that are on the
Wisconsin DNR endangered,
threatened, or watch lists. Unless
otherwise indicated, findings refer only
to the 1974-81 period.
ROCK RIVER BASIN (221)
Species Found
  A total of 93 species (excluding the
coho salmon) was taken from the 827
locations sampled in this basin (Ta-
ble 3). This included 3 endangered
species (gravel chub, striped shiner,
and slender madtom), 1 threatened
(Ozark minnow), and 9 watch species.
Reproducing Populations
  In the Rock River basin, 88 species
are known to have reproducing popula-
tions. The presence of reproducing
populations of 5 other species is ques-
tionable: (1) rainbow trout (there are
no records of natural reproduction),
(2) coho salmon (Oncorhynchus
kisutch ) (taken from Nine Spring
Creek, but not listed in any table in
this report since they were known to
have escaped from the Nevin Fish
Hatchery; reproduction has not been
reported), (3) muskellunge (occur-
rence based on fish management
records from Fox Lake where they
have been stocked), (4) river shiner
(a single specimen from the Rock
River at Watertown in 1977 that may
have been a result of fish manage-
ment's restocking program), and
(5) striped shiner (a single specimen
from the Rubicon River below Hart-
ford). Reproduction is impossible for
the American eel because it does not
spawn in fresh water.
  Brook trout reproduction is limited
to small areas in 2 streams in the basin,
and brown trout are known to
reproduce in very limited areas in 3
streams.
Common and Rare Species
   The 5 most commonly found species
(caught at the highest percentage of
complete stations) were bluegill
(44%), white sucker (43%), blunt-
nose minnow (42%), green sunfish
(37%), and black bullhead (34%)
(Table 3).
  The 13 rarest species (caught at 5 or
fewer of all the stations) were Ameri-
can brook lamprey, American eel,
cisco, muskellunge, goldfish, silvery
minnow, river shiner, striped shiner,
pugnose minnow, silver redhorse, river
redhorse, greater redhorse, and burbot.
Differences Between Basins
and Time Periods
   Of the 93 species found in the Rock
River basin, 23 were not found in the
Sugar or Pecatonica River basins (Ta-
ble 6). However, the muskellunge and
striped shiner, whose natural repro-
duction in the basin is questionable,
are 2 of these.
  Three species of fish have not been
previously reported from this basin -
river shiner*, river redhorse, and
greater redhorse (Table 7).
  Seven species are apparently no
longer present in the Rock River basin
(Table 8). The weed shiner, flathead
catfish, and western sand darter were
taken only before 1929; the shortnose
gar was taken at only 1 station in 1948
(and included in the 1960-73 time pe-
riod); and the finescale dace, bullhead
minnow, and longear sunfish were
most recently taken in the 1960-73
time period. It is questionable if a re-
producing population ever existed for
the flathead catfish or shortnose gar.
  Seven species not taken between
1929 and 1973 from the basin (Ta-
ble 9), including the striped shiner*,
were collected during the 1974-81 pe-
riod.
*Natural reproduction in basin is
questionable
SUGAR RIVER BASIN (222)
Species Found
  The 174 locations sampled in this
basin yielded 72 species (excluding the
grass carp) (Table 3). This included 2
endangered (gravel chub and starhead
topminnow), and 6 watch species.
Reproducing Populations
  In the Sugar River basin, 66 species
are known to have reproducing popula-
tions. The presence of reproducing
populations of 5 other species is ques-
tionable: (1) northern brook lamprey
(only 2 specimens from Willow
Creek), (2) and (3) rainbow and
brook trout (no streams in this basin
known to have natural reproduction),
(4) grass carp (Ctenopharyngodon
idella) (illegally imported into state
and chemically removed from Maloney
Pond; not listed in any table in this re-
port since all specimens are believed to
have been destroyed), (5) yellow
perch (also caught in Maloney Pond
before it was chemically treated and
were replanted afterwards; this private
pond has a controlled outlet and natu-
ral reproduction has not been docu-
mented in other areas). The American
eel does not spawn in fresh water.
  There are only 4 streams that are
known to have reproducing popula-
tions of brown trout, 1 of which
(Mt. Vernon Creek) has excellent re-
production (C. Brynildson, Wis. Dep.
Nat. Resour., pers. comm.).
Common and Rare Species
  The 5 most commonly found species
(caught at the highest percentage of
complete stations) were white sucker
(76%), creek chub (66%), Johnny
darter (60 %), bluntnose minnow
(55%), and brook stickleback (47%)
(Table 3).
  The 24 rarest species (caught at 5 or
fewer of all the stations) were northern
brook lamprey*, American eel, rain-
bow trout*, brook trout*, grass picker-
el, goldfish, silver chub, rosyface
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