With the July Fourth holiday approaching, the Texas Parks and Wildlife Department urges boaters to declare their independence from zebra mussels by keeping their watercraft free of the small but insidious invaders. Zebra mussels are a threat to the state's aquatic ecosystems, private property and water-related infrastructure, such as water supply systems. \"The British may not be coming, but the zebra mussels unfortunately are," said Brian Van Zee, a TPWD Inland Fisheries regional director. "We've got to try to keep them from spreading. If we don't, the impact on everything from fishing to our water supply could be devastating." Of immediate concern are North Texas lakes, such as Ray Hubbard, Lewisville, Grapevine, Possum Kingdom, Granbury and others. These lakes are on the Trinity and Brazos River systems and are heavily used by recreational boaters who could be unknowingly transporting zebra mussels from other bodies of water. In their larval form, zebra mussels are microscopic and impossible to see with the naked eye, so even a boat that appears clean can be carrying zebra mussels. A simple three-step procedure is the easiest way to prevent the spread of zebra mussels and other aquatic invasive species: Clean all vegetation, mud, algae and other debris from the boat and trailer before leaving the lake. Drain all water from the motor as well as the live well, bilge, bait buckets and any other compartments or systems that hold water before leaving the lake. Dry the vessel and associated equipment for a minimum of seven to 10 days during the months of May through October or for 15 to 20 days from November through April. These drying times are approximations, and conditions such as cooler air temperatures, higher humidity and whether or not the vessel is kept in dry storage should be considered. For more information on zebra mussels and other invasive species, visit www.texasinvasives.org.