After hundreds of dead carp were found in mid-August floating in Alder Lake in New Dundee, fish from the millpond were tested. The Ministry of Natural Resources and Forestry has now confirmed those samples tested positive for the koi herpesvirus.
The highly contagious virus is linked to large fish die-offs but only affects carp, koi and goldfish. "The disease is most often seen when water temperatures increase and fish are crowded especially during spawning," ministry spokesperson Jolanta Kowalski said in an email.
Residents living around the horseshoe-shaped millpond noticed juvenile carp floating dead at the shoreline in mid-August. In the days that followed, residents saw larger, more mature carp dying as well.
Mark Servos, Water Institute member and professor in the Department of Biology who visited the lake during the die-off, said those observations fit the pattern for the virus. "It affected the younger fish first and then the older fish, so it's the exact pattern for koi herpesvirus. It's exactly what you would expect," he said, adding there's very little that can be done about it.
And while the Alder Lake die-off was "ugly," Servos said it might actually benefit the reservoir.
Carp are an invasive species. They disturb the bottom of water bodies, causing nutrients to stir up and potentially feed algal blooms, he said. Without carp, there is more natural growth of plants and the water in the lake will become clearer, he added. "It was terrible that this occurred, but the fact that it's going to knock back the carp is probably going to have positive ecological consequences for the lake in the long term," he said.
Read the full article in The Record.
A virus that infects carp is the likely cause of the death of hundreds of fish that washed up on the shore of Alder Lake in August, according to the Ministry of Natural Resources. - David Bebee , Waterloo Region Record
