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March - April 2010 Issue MWC Project Compliments Culvert Replacement Restoring Fish Passages On Small Streams Trout and other stream-dwelling fish are notorious
for hanging around favorite pools and riffles.
Individual fish will set up for several weeks in holes with good
over-head cover, and even defend feeding zones.
But over the course of a year, fish need to move up and down the
watercourse seeking new microhabitats when flow, temperature and other
conditions change. Trout need
to reach spawning habitats where gravel is washed clean, and may migrate
to the mouths of cool tributaries and springs when the water warms in late
summer. Among the most detrimental obstacles to fish
movement in streams are perched culverts set too high during road
construction. They make it
difficult, if not impossible, for fish to move upstream, especially during
low flow periods. Perched
culverts also can impound fairly large areas, contributing to stream
warming and sedimentation. Some
encourage beavers to build more and bigger impoundments. Thanks to increased availability of federal funds
for “aquatic-organism passage” more culverts are being reconstructed.
One such project occurred recently on Big Murphy Creek on Hiawatha
National Forest land in Schoolcraft County.
There, the U.S. Forest Service removed a key culvert as part of
habitat improvement work to benefit brook trout.
In 2010, the Forest Service will team with the Michigan Wildlife
Conservancy to improve a 2,000-foot stretch of Bear Creek, a tributary to
Big Murphy Creek. The work is
less than a mile upstream of the culvert re-construction, which has
greatly increased passage of brook trout, especially juveniles. In 2006, in a small stretch of Bear Creek,
installation of log bank covers narrowed and deepened the stream, speeded
the current and restored overhead cover.
Electrofishing one year before installation and three years after
installation revealed that numbers of brook trout 6-9 inches in length
doubled despite moderate fishing pressure.
Brook trout reproduction remained high.
The initial project created more pool habitat and overhead cover in
what had been a shallow, wide channel.
Average channel width decreased to about 50% of pre-project width.
So, the joint Forest Service – Michigan Wildlife Conservancy
project in summer of 2010 is expected to have great impact—greatly
expanding this work and enhancing benefits from the culvert
re-construction. Perched culverts are under scrutiny in the Lower
Peninsula as well. Federal
funds will likely be used in Oceana County to replace culverts on the
White River and several of its tributaries.
Several of those culverts are as old as 40 years.
Some are just 12-14 inch diameter pipes, but at some road crossings
there are two or three larger diameter perched culverts.
So, projects can become quite expensive. “This type of work benefits all stream fish and a variety of other wildlife,” says Chuck Bassett, a biologist who oversees Forest Service fish projects in the Central Upper Peninsula. “It’s not just about salmon, steelhead and other anadromons species that migrate from the Great Lakes.” |
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Copyright 2012, Michigan Wildlife Conservancy.
6380 Drumheller Road
PO Box 393, Bath, MI 48808 Phone: 517-641-7677 Fax: 517-641-7877 E-mail: wildlife@miwildlife.org
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