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

Methods,   pp. 4-8 PDF (3.2 MB)


Page 4


Turtle Creek (Rock River basin) -looking up-
stream at habitat of the greater redhorse.
Pecatonica River at County Trunk 0 with Mineral
Point Branch coming in on the right.
  The average annual precipitation
within the Greater Rock River basin is
80 cm (76-84 cm) according to Na-
tional Weather Service data. The aver-
age gradient for the Rock River above
the mouth of the Crawfish River (in
Jefferson Co.) is 23 cm/km. It de-
creases to 18 cm/km below the mouth
of the Crawfish River. The average gra-
dients for the Pecatonica and Sugar
rivers, however, are considerably
higher at 76 and 72 cm/km, respec-
tively. The discharges near where the
Rock, Pecatonica, and Sugar rivers
cross the state's border average 48, 19,
and 9 m3/sec, respectively.
  The dominant land use in the
Greater Rock River basin is agricul-
tural, including both crop and pasture
lands. The turbidity of many streams
in the basin, especially in the Pecaton-
ica River basin, can be traced in large
measure to the activity of dairy and
beef cattle in the streams and on the
stream banks. The eutrophic condition
of the water in many streams and lakes
in the Greater Rock River basin, espe-
cially in the Rock River basin, can be
traced to municipal sewage treatment
facilities as well as to the agricultural
land practices (Wisconsin Department
of Natural Resources 1971, 1971, 1971,
1976).
METHODS
      Data Sources and Time
      Periods
        All collections except 4 are divided
      into 3 time periods: 1900-28, 1960-73,
      and 1974-81. The earlier records pro-
      vide the basis for assessment of
      changes over time in distribution of
      fish species within the Greater Rock
      River basin.
        If a location was sampled within a
      time period more than once, only 1 col-
      lection is used in the counts of number
      of stations sampled and number of sta-
      tions at which a species was taken.
        Stations were classified in one of
      two ways during the 1960-73 and 1974-
      81 periods, depending on how the sam-
      ples were taken: complete (those in
      which all species collected were
4    recorded and identified), and partial
(those in which sampling effort and/or
species identification were incomplete
and therefore did not yield adequate
assessment of total species
composition).
  1900-28 Period. Collections from
this period were made at 126 stations
in the Greater Rock River basin (Ta-
ble 2), primarily by one or more of the
following individuals: Cahn (1927)
and C. W. Green, L. C. Stuart,
C. L. Turner, G. Wagner, Schultz,
Tarzwell, E. Creaser, and
J. L. Griffith (names taken from the
original field notes). Most specimens
were verified by Dr. Carl Hubbs or
Dr. Greene. The majority of the spe-
cies locations were cited by Greene
(1935).
  The stations sampled were located
on 64 streams and 18 lakes in the
Greater Rock River basin (Table 2).
Thoroughness of sampling effort is un-
known, and therefore calculation of
percent occurrence of each species was
not attempted.
  1960-73 Period. Complete collec-
tions from this period were made at
259 sampling stations on 99 streams
and 13 lakes in the Greater Rock River
basin (Table 2). An additional 49 par-
tial collections, which increased the
number of streams sampled by 5 and
lakes by 16, came from written records
provided by fish management person-
nel, and sport and commercial fisher-
men. The data from these partial sam-
ples were therefore kept separate in
Tables 2 and 3, and are not included in
the percentages of total stations sam-
pled in Table 3. All collections (except
4 made between 1946 and 1959 from
the 49 partial stations) were made be-
tween 1960 and 1973.


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