DAY COUNTY, S.D. (KELO) — An adult zebra mussel was found in Enemy Swim Lake in Day County, officials have confirmed.

The mussel was found near the NeSoDak Beach in early July according to the South Dakota Department of Game, Fish and Parks.

“Lake residents and GFP spent several weeks looking for additional mussels. One adult, of similar size to the first mussel discovered, was found near the Church Bay boat ramp,” Area Fisheries Supervisor Mark Ermer said.

Groups from Enemy Swim Lake worked at keeping zebra mussels out of the lake in 2021 after nearby Pickerel Lake was infested in July 2020. Pickerel Lake is less than 10 miles away from Enemy Swim Lake.

The lake is now considered infested with zebra mussels and all watercraft on the lake, motorized and non-motorized, need to be inspected by GFP officials. The inspection sites have hot water sprayers that are able to kill any invasive mussel tissue or aquatic species.

Authorities encourage boaters to inspect their watercraft to feel for roughness that may indicate a zebra mussel. They also recommend completely draining and drying boats to make sure invasive species aren’t transferred to the water.