Nebraskaland

January-February 2021 • Nebraskaland 49 Since first appearing in the Missouri River in Nebraska in 1996, Asian carp have spread up every tributary as far as they can, in most cases only stopping when blocked by a dam. Silver and bighead carp have been found on the Platte River as far west as Lexington, the Elkhorn as far as Neligh, the Loup as far as Burwell and the Big Nemaha as far as Tecumseh. The invasive fish are found in smaller tributaries, including Salt Creek, a Platte tributary, and other waters in its watershed. Fisheries biologists want to know how many smaller tributaries Asian carp have infested and how far upstream they have moved. But surveying small streams is time-intensive work. They hope a new technology that tests water for environmental DNA will help. DNA is naturally released into the water by fish, and the tests can identify the species present in an area or farther upstream. The University of Nebraska-Lincoln is testing the process, with funding for the work provided by a U.S. Fish and Wildlife Service grant through the Nebraska Game and Parks Commission. When more is known about the range of silver and bighead carp, biologists will be able to identify areas of concern and take measures to remove them or keep them out of sensitive areas where they could out-compete native fish for food. Little research has been done on the effects of Asian carp on native fish in Nebraska, but biologists have noticed a slight decline in the body condition of paddlefish, another filter feeding fish found in the Missouri River. Other recent research by the university found major tributaries are likely the primary habitat for silver and bighead carp, which use the swift, deep channelized Missouri River to move between the smaller rivers. The fish are still numerous in the Missouri, especially in backwaters and slack water areas behind training dikes, and below Gavins Point Dam. Biologists are happy the fish haven't made it past that point, something that would open the Niobrara River and others to the species and become a headache for recreational boating in Lewis and Clark Lake. The only way they could make it farther upstream is if unknowing anglers using small fish for bait moved them. For questions or to report sightings of Asian carp or other aquatic invasive species, contact Kristopher Stahr at ngpc.ais@nebraska.gov or 531-500-3746. Nebraska Game and Parks Commission fisheries biologists Thad Huenemann, Kirk Steffensen, Jeff Schuckman, Brad Newcomb and Jeff Jackson, and Mark Pegg, a fisheries ecology professor in the University of Nebraska-Lincoln School of Natural Resources, contributed to this report. Asian Carp's Status in Nebraska Tim McCoy, assistant director of the Nebraska Game and Parks Commission, watches silver carp jump around his boat at the mouth of the Little Nemaha River on a river tour in 2013. Asian carp are found in larger rivers throughout eastern Nebraska. They are also found in many tributaries of the Missouri River and the Salt Creek watershed. MAP ILLUSTRATION BY TIM REIGERT

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