Koi virus identified as cause in Clintonville
The Pigeon Lake Protection and Rehabilitation District, working with the state DNR, has uncovered the cause of the carp die-off in the watershed:
A virus first identified in ornamental koi fish in the 1990s that has now spread worldwide.
The virus, which causes Koi Herpesvirus Disease (KHVD), is a distinct strain that targets only koi and carp, according to the Wisconsin Department of Natural Resources website. The virus was first identified in Wisconsin in 2014.
According to DNR Fish Biologist Laura Stremick-Thompson, in a 2014 article: “the public is not at risk from the koi herpes virus and from what we have seen in other states, sport fish and forage fish … have not been harmed. However, DNR encourages use of protective clothing such as gloves in removing the dead carp due to other bacteria the fish may be hosting.”
KHVD caused significant carp die-offs in New York in 2005, in Ontario, Canada in 2007, in Michigan in 2011, and in the Madison area in 2014 and 2017. Onset of the virus appears to occur as water temperatures climb, so residents can expect further die-offs as the temperature increases.
There is no cure for the disease at present. People may want to bury dead carp that wash up on their property.
“They’re good fertilizer,” said District Board member Myron Radtke.
Mitigating foul aroma
The Lake District will be collecting and disposing some of the dead fish to mitigate the foul aroma.
The presence of the virus in other states has been linked to the release of ornamental fish such as domesticated koi into lakes and streams.
“While a nuisance,” said Pigeon Lake District Board Chair Jon Pahl, “at one level this virus can be a benefit to the lake ecosystem. As anyone who has regularly fished the lake knows, we’ve had an overabundance of carp since the lake was drawn down in 2019. This die-off should help the sport fish to thrive.”
Unfortunately, this threat to the carp population means the Ruff Fish Tournament, scheduled for July 16 this year, will have to be postponed.
Since 2019, the lake district, working with the DNR and Shadows on the Wolf, has stocked Pigeon Lake with over 15,000 largemouth bass, 9,000 northern pike, 8,000 crappie, 8,000 bluegill, and 3,000 perch.
Anecdotal reports from spring anglers on Pigeon Lake suggests a good summer ahead–with some nice bass, pike and panfish being taken already.
“It promises to be a good summer for fishing and other recreational activities on Pigeon Lake,” said Pahl. “This disease does not reflect on the quality of the water in the lake, or on the overall health of the watershed.”
The Lake District is working with Onterra Lake Management to develop a comprehensive plan for Pigeon Lake.
A public meeting with Onterra representative Tim Hoyman, an environmental biologist and lakes expert, will be held at 6:30 p.m. Wednesday, July 13, at the Clintonville Community Center.