Zebra mussels, an invasive species that can have many serious impacts on local reservoirs and rivers, were found last week in Lake Grapevine, according to a Texas Parks and Wildlife news release.
A United States Geological Survey team found a juvenile zebra mussel attached to a sampler on the southern end of the lake on June 22, according to the TPWD news release. Plankton samples collected in May also revealed the presence of microscopic larva.
“With the boating season in full swing and the busy Fourth of July holiday right around the corner, it’s very important for all boaters to understand that if they are going to be enjoying the lake they need to clean, drain and dry their boat and equipment every time they leave the water – it’s not just the right thing to do, it’s the law,” said Brian Van Zee, TPWD Inland Fisheries Regional Director.
TPWD conducted follow-up surveys failed to find any other mussels, indicating the one the team found is likely a new introduction, and both agencies will monitor the lake closely.
The rapidly-reproducing zebra mussels can have serious economic, recreational and environmental impacts on Texas reservoirs and rivers, according to TPWD. Zebra mussels can harm native freshwater mussels and other aquatic species, affect water clarity and cause harmful algal blooms, cover shoreline rocks and litter beaches with sharp shells, clog water intakes, damage or increase maintenance on hydroelectric and other facilities using raw surface water, and damage boats and motors left in infested waters.
“Zebra mussels shouldn’t deter anyone from visiting and enjoying the water this summer,” Van Zee said. “But preventing the spread of zebra mussels needs to be a priority for everyone – regardless of which lake you’re visiting.”
Van Zee said lake visitors should properly clean, drain and dry their wet equipment. If you are moving your boat from a slip on a lake known to have zebra mussels, contact TPWD at 512-389-4848 or email [email protected] so TPWD can provide guidance and support to reduce the risk of spreading zebra mussels.
Currently throughout the Trinity River Basin, five lakes are classified as infested, meaning they have an established, reproducing population of zebra mussels: Lakes Bridgeport, Eagle Mountain, Lewisville, Livingston and Ray Roberts. Five lakes are classified as positive, meaning zebra mussels or their larvae have been documented more than once: Lakes Grapevine, Lavon, Richland Chambers, Worth and Fishing Hole Lake. One lake, Lake Ray Hubbard, is classified as suspect, meaning zebra mussels or their larvae have been positively identified one time.
TPWD and partners will continue monitoring high risk lakes in Texas, installing signage and reminding boaters to clean, drain and dry their equipment when leaving public boat ramps.
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 both adults and larvae can survive for days in or on boats transported from a lake. 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.
Click here for more information about zebra mussels.