Dr. Chris Jerde, University of Notre Dame, with ruffe captured in the Bad River, Wisconsin. - Photo Credit: Henry Quinlan, USFWS
The Service's Ashland Fish and Wildlife Conservation Office (FWCO) lab was transformed into a water filtration station this November to obtain eDNA from water samples taken from Chequamegon Bay and the Bad and White Rivers in Wisconsin. The eDNA will allow testing of genetic markers for ruffe, one of a dozen invasive fish species targeted by the U.S. Fish and Wildlife Service for which the University of Notre Dame is developing markers for Great Lakes eDNA application. The work is supported by Great Lakes Restoration Initiative funds, and is identical to the process of eDNA marker development that was used to detect Asian carp eDNA in the Chicago Area Waterway System (CAWS).
Dr. Chris Jerde of the University of Notre Dame, worked closely with Jessica Zakovec of Ashland FWCO and Chris Olds of Alpena FWCO, to sterilize the lab and set up the water filtration operation using equipment provided by Dr. Jerde. Fishery biologists from Ashland FWCO and Alpena FWCO collected water samples from Chequamegon Bay, and the Bad and White rivers, Wisconsin. Chequamegon Bay and the Bad River are known to contain ruffe, whereas the White River sample collection was upstream of a dam from waters believed to be uninhabited by ruffe. Upon completion of water sample collection, bottom trawl tows were made through the area from which water samples were obtained in an attempt to capture ruffe specimens.
Over the course of three days, Jessica, Chris, and Glenn Miller of Ashland FWCO, filtered 75 two-liter bottles of water through 150 individual filter papers. The filter papers which may contain ruffe DNA were immediately frozen and transported to the lab at the University of Notre Dame for polymerase chain reaction (PCR) marker testing. The capture of 95 ruffe from one of the trawl tows provides a positive indication that ruffe were present in one of the waterbodies at the time of sampling. Tissue from the ruffe captured during the week, as well as tissue from frozen ruffe which were captured this past summer by Ashland FWCO in the St. Louis River, MN/WI, was gathered by Dr. Jerde for genetic marker testing.
In the coming weeks, researchers at the University of Notre Dame will test the samples collected for ruffe DNA. Their results will shed light on whether or not the approach used to detect Asian carp in the CAWS can also be used to detect ruffe in the Great Lakes, or whether modification to the methodology (e.g. bottom grab water sample) is required for ruffe. If successful, the USFWS and other fishery agencies will be armed with another tool to determine if ruffe have expanded beyond their current distribution in Lake Superior into other Great Lakes.