AUSTIN –The Texas Parks and Wildlife Department (TPWD) has added O.H. Ivie Lake near San Angelo to the statewide list of lakes designated as positive for invasive zebra mussels after multiple specimens were found in the lake in 2019.

In March 2019, four adult zebra mussels were discovered by the Colorado River Municipal Water District (CRMWD) in an above ground storage tank that is part of the lake’s water transmission system near San Angelo. Given the presence of zebra mussels in the water transmission system, the CRMWD and TPWD continued to follow up with additional sampling at the lake and in November found a zebra mussel veliger larva near the Concho Recreation Area boat ramp.

“TPWD and CRMWD are going to continue to monitor the situation to determine if zebra mussels have established a reproducing population in the lake, but we are also asking the public to help us by keeping an eye out and reporting any zebra mussel sightings at O.H. Ivie Lake to [email protected],” said Monica McGarrity, TPWD Senior Scientist for Aquatic Invasive Species Management.

O.H. Ivie is now the sixth lake in the Colorado River Basin with invasive zebra mussels along with Austin, Lady Bird, Lyndon B. Johnson, Marble Falls, Travis and Walter E. Long. Because O.H Ivie is miles upstream of where they have been found before in the river basin, it is likely they were transported to the lake on a boat or other equipment.

“It is essential that boaters be vigilant to not spread zebra mussels to nearby lakes that are now at higher risk due to proximity of zebra mussels,” said Brian Van Zee, TPWD Inland Fisheries Regional Director. “It is important for all lake users to protect our lakes by cleaning, draining and drying their boats and equipment every time they leave the water and properly decontaminate their boat if it was stored in the water on lakes with zebra mussels.”

As of March 2020, zebra mussels are found in 30 Texas lakes across five river basins. A status map and full list of these lakes can be found on the TPWD website.

TPWD and partners monitor for invasive mussels in Texas lakes, but anyone who finds them in lakes where they haven’t been found before or who spots them on boats, trailers or equipment that is being moved should help identify and prevent new introductions by immediately reporting the sighting to TPWD at (512) 389-4848 or by emailing photos and location information to [email protected].

The rapidly reproducing zebra mussels can have serious economic, recreational and environmental impacts on Texas reservoirs and rivers. Zebra mussels can harm aquatic species, cover rocks, beaches, hard surfaces with sharp shells, clog water intakes, damage or increase maintenance on facilities using raw surface water, and damage boats stored in lakes with zebra mussels.

In Texas, it is unlawful to possess or transport zebra mussels, dead or alive. Boaters are required to drain all water from their boat and onboard receptacles before leaving or approaching a body of fresh water to prevent the transfer of zebra mussels and other invasive species. Zebra mussel larvae are microscopic and can survive for days in residual water, and adult zebra mussels can survive even longer out of water, especially in cooler months. The requirement to drain applies to all types and sizes of boats whether powered or not – personal watercraft, sailboats, kayaks, canoes or any other vessel used on public waters.

More information about zebra mussels can be found online at tpwd.texas.gov/ZebraMussels. A short instructional video on how to properly clean, drain and dry boats and equipment can be found on the TPWD YouTube channel at https://youtu.be/DMlEwbXmLx8. Information for marinas and owners of boats stored in the water on lakes with zebra mussels can be found at tpwd.texas.gov/decon.