Fisheries biologists recently sampled water from eight locations in the Tennessee River Basin to determine the presence or absence of genetic material from two invasive Asian carp species, bighead and silver carp, within reaches of the river system. The project was conducted by the U.S. Fish and Wildlife Service (USFWS) from the Carterville Fish and Wildlife Conservation Office in Marion, Illinois, with assistance from the Alabama Wildlife and Freshwater Fisheries Division (WFF), the Mississippi Department of Wildlife Fisheries and Parks (MDWFP) and the Tennessee Wildlife Resources Agency (TWRA).
Three Asian carp species, grass, bighead and silver carp, have become established in the Mississippi River Basin and have severely impacted native fish populations, disturbed aquatic food webs and altered aquatic habitats in many locations in the Midwestern United States. Additionally, their relatively large size and the habit of silver carp to jump high above the surface of the water when disturbed by passing watercraft poses a serious safety concern for boaters. Populations of these nuisance fish have steadily expanded up many tributary streams of the Mississippi River and now threaten to invade and impact the Ohio and Tennessee Rivers and their tributaries.
The invasive species.
In Alabama, WFF biologists assisted with the collection of water samples below Wilson, Wheeler and Guntersville dams on the Tennessee River as well as from two tributaries, Bear Creek and Elk River. MDWFP and TWRA biologists assisted in collecting samples at Bay Springs Lock and Dam on the Tennessee-Tombigbee Waterway in Mississippi and below Nickajack and Chickamauga dams in Tennessee. A total of 700 water samples were collected during this cooperative monitoring effort by the four agencies.
Collected water samples will be processed and analyzed by the USFWS’s Whitney Genetics Lab in La Crosse, Wisconsin, for the presence of environmental DNA, or eDNA, unique to bighead and silver carps. EDNA can be left in the environment in the form of scales, cells, feces or mucus. At present, eDNA evidence cannot verify whether live Asian carp are present, whether the DNA may have come from a dead fish, or whether water containing Asian carp DNA may have been transported from other sources such as bilge water, storm sewers or fish-eating birds. Once processed, eDNA results from sampling in the Tennessee River Basin will be made available at: http://www.fws.gov/midwest/fisheries/eDNA.html.
The objective of this project is to establish the location of the leading edge of the upstream invasion by these species within the Tennessee River system. Bighead carp are already known to be established as far upriver as Wheeler Reservoir and silver carp are believed to be established as far upriver as Pickwick Reservoir. Silver carp appear to have the greatest potential to negatively impact Alabama’s aquatic and fisheries resources and to present a hazard for boaters. Knowing the location of Asian carp in river systems is critically needed by fisheries resource agencies to better plan strategies to slow the spread and expansion of their populations.
For more information on the science of eDNA in the fight against Asian carp, watch the video at: http://youtu.be/xXwply6ahQ8.
Contacts: Nick Nichols (Ala.-WFF); 334-242-3883
Kaitlin Steiger-Meister (USFWS); 612-713-5317
