A large die-off of invasive common carp at J.E. Roush Lake in J.E. Roush Lake Fish & Wildlife Area near Huntington in 2017 failed to reduce the fish’s numbers, according to recent surveys of the lake.

The die-off was triggered by the Koi herpesvirus (KHv), a contagious virus often found in carp, koi, and goldfish. The virus produces gill lesions that eventually cause suffocation.

DNR biologists were hoping the die-off would reduce the number of common carp in the lake, but the aquatic invasive species is still the dominant fish in the 900-acre flood-control reservoir.

Aquatic invasive species are plants, animals, and diseases that harm fish populations by competing with native species and changing aquatic habitats.

“We don’t know the total number of carp that were killed, but apparently not enough to dent the population,” said Jed Pearson, DNR fisheries biologist.

Last summer Pearson and his sampling crew conducted a follow-up survey of the lake’s fish population using an electrofishing boat, gill nets, and trap nets.

During the survey, 69 common carp were collected measuring up to 24 inches long. The catch rate was higher than ever. Carp ranked second in number only to white crappies. They also ranked first by weight. Thirty-one goldfish, a close relative to carp, were also caught. The largest were 10 inches long.

“Carp have caused problems at J.E. Roush Lake ever since the lake was created decades ago, despite a DNR attempt to eradicate them prior to impoundment. Many survived and quickly overran the lake,” Pearson said.

Carp are a nuisance because they compete for food and space with other popular sport fish. They also muddy the water by roiling the bottom and displace the nests of spawning fish.

“Common carp are one of the most destructive fish we have in Indiana lakes and rivers,” Pearson said.

Never use common carp as live bait and do not transfer carp from one water body to another. If you catch a common carp, eat it or use it as cut bait or garden fertilizer.

Anglers who notice significant numbers of dead or dying carp in Indiana public waters are asked to report them to Austin Taylor, restoration biologist, DNR Division of Fish & Wildlife, 317-232-5821, ataylor1@dnr.IN.gov

For more information on common carp generally, visit dnr.IN.gov/files/COMMON_CARP.pdf.

To view all DNR news releases, please see dnr.IN.gov.

Media contact: Jed Pearson, fisheries biologist, DNR Division of Fish and Wildlife, 260-244-6805, JPearson@dnr.IN.gov.