Upper Midwest Environmental Sciences Center
Pool 26, Upper Mississippi River 2000 Fish Collection Summary
This report is a bullet summary of the Long Term Resource Monitoring Program's (LTRMP) fish collection efforts conducted by the Great Rivers Field Station on Pool 26, Upper Mississippi River during 2000. Information on changes in fish catch over all years can be obtained from the Graphical Fish Database Browser.
- 386 fish collections were conducted using 10 gear types (Table
2.4).
- High water levels in the upper reach of Pool 26, low water levels
in the extreme lower reach, and high current velocities throughout the
pool caused minor sampling problems during period 1.
Seining, in particular, was problematic because water levels were often
outside the range of depths acceptable for seining (Table
2.4; Figure 1.4).
- Period 1 missed samples that included one backwater, contiguous, offshore,
large hoop net collection; one main channel border, wing dam, mini fyke
net collection; and four tailwater zone, trawling collections (Table
2.4).
- Period 3 missed samples that included one side channel border and mini
fyke net collection (Table 2.4).
- The duty cycle setting on the electrofishing
unit was erroneously set at 2.5% rather than at the standard 25% during
periods 1 and 2. Nonetheless, we believe it is unlikely that the deviation
in duty cycle had a major effect on our catch because the number of
species collected, the species composition, and the mean catch-per-unit-effort
for 2000 were within the range of values seen in previous years.
- Of the 386 fish collections, 372 were from randomly selected sites. Fourteen
collections were made at fixed sites.
- Main channel border, unstructured; side channel border; and backwater,
contiguous, shoreline strata received the most sampling effort (Table
2.4).
- 28,511 fish were collected representing 63 species and 1 hybrid (Table
3.4).
- Fish distribution records for the Upper Mississippi River (Pitlo et
al. 1995) document 99 fish species from Pool 26.
- The LTRMP species total for Pool 26 before the 2000 season was 87;
one white perch (Morone americana) was collected, adding a new
exotic species to the Pool 26 species total, and increasing the total
to 88 species (Table 3.4).
- 123 bighead carp were collected in 2000, the greatest yearly total
to date. This exotic species
was first collected in 1991 (one specimen; Table 3.4).
- Eight silver carp were collected in 2000, which is the third year
this exotic has appeared in the catch (Table 3.4).
- One western sand darter (Illinois-listed endangered species) was collected,
and no Illinois-threatened species were collected (Table
3.4).
- Mean catch-per-unit-effort and standard error for fish collected
by gears using stratified random (Tables
4.4-13.4) and fixed-site sampling (Tables
15.4-21.4) for each stratum are shown.
-
Length distributions for selected species of fish are shown in Figures 2.4 to 19.4.
Content manager: Jennie Sauer
Page Last Modified: April 17, 2018