The Iowa Department of Natural Recourses on Tuesday said three juvenile zebra mussels were found attached to docks and hoists removed from East Okoboji Lake.
Biologists says the discovery increases "the likelihood that the invasive species may be establishing itself in the popular northwest Iowa chain of lakes."
"We're not going declare an infestation because these things do happen," said Mike Hawkins, Spirit Lake District fisheries management biologist. "You see isolated incidents or isolated animals and they don't take off and they don't form a naturally-reproducing population -- they kind of fizzle out. So, we are seeing very, very early indications of zebra mussels and -- absolutely -- there's always a possibility that this could fizzle out. There is some hope still."