The Iowa Department of Natural Resources is considering a new way of determining which species of fish are swimming in Iowa lakes and streams.
The agency currently uses electrofishing in the spring and fishnets in the summer and fall to catch fish, assess their health, and then release them back in the water. Andrew Carlson, the DNR’s Fisheries Biologist for northwest Iowa, said there may be a way to collect water samples and get the same kind of data. “Each fish that’s out in the water is going to shed deoxyribonucleic acid or DNA into the water,” Carlson said, “and you can actually look at the presence or absence of different species, potentially the relative abundance of different species as well using the shedding rates for various species.”
Research published in 2022 found scientists were able to use environmental DNA in the Pacific Ocean to measure pupulations of fish off the West Coast, information that helped fishing fleets determine how many fish they might catch in an area. Carlson is just back in Iowa after a national conference where the process was discussed. “There’s some other projects throughout the country where they’ve had success tracking fish presence and relative abundance using environmental DNA,” Carlson said. “We’re exploring that in Iowa as well.”
States like Alaska and Washington collect environmental DNA (eDNA) in water samples to track salmon. Pennsylvania and Wisconsin have partnered with the US Fish and Wildlife Service to track invasive species with eDNA. There’s also a national database of aquatic species in various locations around the US, the eDNAtlas, that’s crowd-sourced, with federal and state agencies as well as organizations outside of government contribute information to a national center for wildlife and fish conservation.
(By George Bower, KICD, Spencer/ O. Kay Henderson Radio Iowa)