Field Notes
U.S. Fish & Wildlife Service
Field Notes Entry   
Scour Basins on Big Muddy National Fish and Wildlife Refuge Surveyed for Fish Populations
Midwest Region, July 10, 2005
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There are three large scour holes on the Diana Bend and Overton Bottom Units of the Big Muddy National Fish and Wildlife Refuge. The scours were created by the Missouri river during the flood of 1993 and have since served as a home for a variety of river fish species. Every few years high spring rises reconnect the scour holes to the river providing an exchange of fish and nutrients. This may help productivity yet makes managing these fish populations a greater challenge.

A crew of fishery biologists lead by Cliff Wilson from Columbia Fishery Resources Office surveyed these three scour holes in July. The survey was conducted to determine species richness, diversity, abundance and condition. Electro-fishing and a suite of net types were used to collect game, non-game, and nuisance fish species in each scour hole. The survey produced 3,519 fish including 36 different species from the three ponds. Some of the most interesting fish observed in the scour holes included smallmouth and spotted bass which are species almost never seen in the Missouri river or in scour holes. Other species of interest included: sauger, adult paddlefish and both juvenile and adult bighead and silver carp.

Resource users have an interest in establishing healthy recreational fisheries in these scour holes. Some of the ideas being considered include sealing them off from their flood plains to prevent fish from being lost to flooding, adding additional vegetation to create better habitat for the fish, and having the states conservation department stock catfish.

Earlier this year, Friends of the Big Muddy, a refuge volunteer group, sank Christmas trees in the scour holes to create habitat for the fish. This spring, Columbia FRO stocked adult largemouth bass and redear sunfish, donated to the Service from an overpopulated private pond, into the scours to boost sport fish populations. Since this stocking, high river levels in June reconnected the scours to the river. It is suspected that this July survey will give biologist an opportunity to determine if some of these fish were lost during the flooding events. Knowing if fish will be lost during these events will be valuable information when stocking is considered.

Columbia FRO will continue to monitor these scour holes and provide management recommendations to refuge managers to be used for bringing about management ideas and regulations that will aid in establishing a healthy population for the benefit of recreational anglers at the refuge. This effort supports the Partnerships and Accountability and Public Use goals of the Fisheries Programs Vision for the Future.

Cliff Wilson, Columbia FRO

Contact Info: Larry Dean, 612-713-5312, Larry_Dean@fws.gov
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