New Zealand mudsnails were recently found in Lake Tahoe by divers, prompting a warning call from authorities about the invasive species.
The creatures, which can potentially disrupt the local ecosystem, have previously been found downstream in the Lower Truckee River near Reno, but never in Lake Tahoe itself, officials announced Thursday.
The small snails were found at the bottom of the lake about a half mile offshore on the south side of the lake, the Tahoe Regional Planning Agency announced.
The mudsnails are about the size of a grain of rice and "are able to colonize new waters quickly and due to their small size are difficult to detect," the planning agency said.
Scientists will begin conducting dives in other parts of the lake to see where else the unwanted aquatic creatures have spread.
State officials ask anyone who finds the animals to report them to the Department of Fish and Wildlife to prevent them from overpopulating.