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New Small Stream Trawl Designs Introduced at Missouri's Natural Resource Conference
Midwest Region, February 5, 2011
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Push Trawling on the Gasconade River. (U.S. Fish and Wildlife Service)
Push Trawling on the Gasconade River. (U.S. Fish and Wildlife Service) - Photo Credit: n/a

New trawl techniques and applications are slowly changing the way fisheries managers can sample mid-western streams and rivers. I recently had the opportunity to present some new applications of our trawls at the annual Missouri Natural Resources Conference in Osage Beach, MO. My presentation introduced Ozark stream managers to new techniques adapted from our big river efforts. Having spent time in graduate school researching an electric seine and conducting many comparative seine depletion studies, I was eager to find a way to mechanize the process. In 2008, I worked with fellow biologist Clayton Ridenour to test our Missouri River Push Trawl on a small and shallow Ozark stream. We used a video recorder to show the success of the push trawl in clear shallow water and through minimal effort were able to collect dozens of native small bodied fishes in each trawl tow by using a unique rock-rolling trawl design developed by Innovative Net Systems. Bolstered by the success of this push trawl effort on a small river, I worked with a graduate student from Oklahoma State in an even smaller non-flowing stream in search of the state endangered Long Lose Darter. The challenge was to sample an area without an improved boat ramp and still use mechanized efforts including towing a trawl behind the boat. We used a 12-foot boat jon boat with a 15hp motor and a modified version of our benthic rock trawl. Our efforts over 2 days proved we could for the first time actively sample benthic fish species over slab and chunk rock substrates within a wide range of water depths (0.3 -3 meters) in confined riverine systems. It is exciting to be on the edge of developing new gears that will provide better sampling tools to managers which will ultimately enable us to more quickly and thoroughly assess the health of our watersheds. The commitment by our agency toward exploring new science along with the innovative thinking of our staff and net designer have allowed our office to introduce 8 new trawl nets to the Midwest in the last six years that can sample any measure of water available throughout our watershed.


Contact Info: Wyatt Doyle, (573)876-1911 ex 111, wyatt_doyle@fws.gov



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