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The Kiap-TU-Wish
Chapter of Trout Unlimited carries out a brushing project on the
upper Kinnickinnic River most winters. Brushing as a habitat improvement
project is based on research by the Wisconsin Department of Natural
Resources. In the DNR Technical Bulletin Number 115, Dr. Robert
Hunt of the DNR points out that “the best stocks of trout (in
abundance and growth rate) tend to be found in meadow-type reaches”.
He also points out that White and Brynildson, in DNR Technical Bulletin
Number 39, advocated establishment and maintenance of a “sturdy
turf” of grasses, broad-leafed annuals and low shrubs through
use of such techniques as controlled burning, periodic mechanical
brush cutting, application of selective herbicides, seeding and
fencing to exclude livestock. They advocated the radical concept
that planting trees beside trout streams should be actively discouraged
in Wisconsin except where there is reasonable evidence that summer
temperatures for trout would be improved by doing so.
Dr. Hunt goes
on to outline the benefits of brushing:
“If increased
solar heat does not produce deleteriously high water temperatures,
reduction of woody shade canopy could have several beneficial consequences
for trout and the sport fishery they sustain:
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Creation
of more desirable habitat for trout as a result of greater growth
of aquatic macrophytes which both provide shelter for trout
directly and constrict flow to increase scouring, deepening
of pools and undercutting of banks.
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Firmer
stream banks consisting of grassy turf less susceptible to erosion;
a gradual narrowing of the stream channel and accentuation of
channel sinuosity rather than the widening and straightening
process associated with tree-lined reaches, particularly reaches
dominated by speckled alder (alnus rugosa).
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Increased
production of aquatic invertebrates used as food by trout due
to increased abundance of aquatic plants that provide aquatic
invertebrates with both substrate and their source of food,
either directly or indirectly.
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An
increase in terrestrial invertebrates accidentally entering
the stream and available as food for trout, particularly during
the summer months when physiological conditions are good for
trout growth but abundance of aquatic invertebrates is often
declining.
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Improved
growth of trout as a result of increased availability of food
and an improved temperature regime for growth.
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Easier
season-long fishing conditions, more hours of angling recreation
and greater harvest of presently underutilized trout stocks
in small streams.”
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The Wisconsin
Department of Natural Resources has carried out research to scientifically
validate this management technique. One such study was carried out
on the Kinnickinnic River in 1972 through 1977. Abundance of trout
increased in 3 of 5 treatment zones along with an increase in legal
sized and quality-sized fish (10 inches or larger) in all 5 zones.
A summary of this study can be found along with other brushing studies
in DNR Technical bulletin Number 162.
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Guidelines
For Management of Trout Stream Habitat in Wisconsin, Wisconsin
Department of Natural Resources, Technical bulletin No. 39,
1967, reprinted 1986. |
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Removal
of Woody Stream bank Vegetation to Improve Trout Habitat, Wisconsin
Department of Natural Resources, Technical bulletin No. 115,
1979. |
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A
Compendium of 45 Trout Stream Habitat Development Evaluations
in Wisconsin during 1953 -1985, Wisconsin Department of Natural
Resources, Technical bulletin No. 162, 1988. |
Wisconsin Department
of Natural Resources Technical Bulletins can be obtained free of
charge by writing to:
WDNR
Bureau of Research
Box 7921
Madison, WI 53707
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