New carp-killing virus discovered in Minnesota for the first time
Researchers from the Minnesota Aquatic Invasive Species Research Center recently confirmed the presence of Carp Edema Virus (CEV) in Minnesota waters, the first time it has been recorded in wild fish in the state. Researchers are paying close attention to this virus, and considering its potential as a biocontrol agent for invasive common carp.
The virus was first discovered in common carp from a fish kill event in Lake Jonathan in Carver County. It was later found in dead common carp from Cottonwood Lake in Lyon County. Both instances were confirmed by the University of Minnesota Veterinary Diagnostic Lab, who also found Koi Herpes Virus (KHV) to be present. Both fish kill events had high mortality.
In 2017, Lake Elysian in Waseca County made news for being the first lake in which KHV was discovered in wild populations of carp in Minnesota. Since then, MAISRC researchers have confirmed KHV in six more Minnesota lakes. Now, they’re exploring whether these pathogens – individually or combined – could be harnessed to control invasive common carp.
“These viruses are promising control options because they only affect carp, and they are easily transmissible and highly lethal,” said Isaiah Tolo, a PhD student on the project. “The presence of these viruses in Minnesota waters give us a chance to study their impact on invasive carp and determine if they are a tool we could use to control this species.”
MAISRC researchers will continue to gather samples from fish kill events this summer to diagnose cause of mortality. Next, the team will work to isolate both viruses, sequence their genomes, and conduct infection trials to ensure they won’t impact native fish. Conducting risk assessments, developing release strategies, and consulting with the public and regulatory agencies will follow.
If you see a fish kill event, please report it to help this research. Go to z.umn.edu/fishkill for an easy-to-use reporting app. Your report will be sent to MAISRC researchers who will collect samples and diagnose the cause of mortality.
Common carp are one of the world’s most ubiquitous invasive species. They dominate the fish biomass of many shallow lakes, rivers, and wetlands in Minnesota, especially in central and southern parts of the state. When they root in the lake bottom for food, common carp destroy native plants, harm waterfowl habitat, and degrade water quality.
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