BRAINERD, Minn. (AP) -- DNR biologists are trying to determine how a single zebra mussel may have gotten into Pelican Lake near Brainerd.

A dock services provider discovered the juvenile zebra mussel attached to a post while removing the dock from the lake.

Biologists with the Minnesota Department of Natural Resources have checked other docks and marker buoys on the lake and have not found any more zebra mussels. The zebra mussel's small size indicates it had not reached a reproductive stage.

The DNR says Pelican Lake will be designated as an infested lake if a zebra mussel population is identified in the lake.