WINTER DECLINES IN UNDER-ICE HABITAT FOR SMALLMOUTH
BASS (MICROPTERUS DOLOMIEUI) AND CENTRACRCHIDS IN OFF-CHANNEL PONDS ALONG THE UPPER MISSISSIPPI RIVER, POOL
12.

Melissa Goerlitz and Jennifer Steinbrecher
Environmental Sciences Program, University of Dubuque,
2000 University Avenue, Dubuque, Iowa 52001


The abiotic water quality variables determining
overwintering habitat for smallmouth bass (Micropterus
dolomieui) and sunfish (Centrarchidae) were monitored
in 3 off-channel ponds along the Upper Mississippi
River in Pool 12, near Dubuque, Iowa and in Jo Daviess
County, Illinois.  Prior to freezeup, depth contouring
was done for each location.  During the winter,
measurements were made through the ice and values
recorded for the following variables:  dissolved
oxygen, pH, specific conductance, temperature, and
turbidity.  Successive maps were made recording the
amount of habitat available through time to these fish
species, using GIS.  The expected winter declines were
seen, and quantified.  These data are useful for the
determination of the probability of winter-kill
occurring in each location.

Keywords:  water quality, fish habitat, bass, sunfish,
overwinter



Melissa Goerlitz
University of Dubuque
Dubuque, Iowa
(319-589-3598
Fax (319)556-8633
email mgoerlitz@univ.dbq.edu
Poster
Student Author