Clean, Drain and Dry Your Boat. Stop Invasive Species!

Invasive plants and animals are a growing threat to Texas waters. They often travel by hitching rides on boats and trailers. Recreational users can play a critical part in preventing the spread of these unwelcome visitors.

Texas law prohibits possession and transport of any exotic aquatic plant or animal listed as harmful or potentially harmful. Before leaving a water body, boaters and anglers must remove and properly dispose of exotic mussels or fragments of exotic vegetation that are attached to their watercraft, bait buckets or other gear. Failure to do so can result in a fine of $25 to $500.

Boaters and anglers must also drain all water from their boat and on-board receptacles before leaving or approaching a body of fresh water anywhere in Texas. This regulation applies to all types and sizes of boats, including paddlecraft and sailboats as well as power boats.

Here are two of our biggest current threats:

Zebra Mussels

hand with 2 zebra mussels The zebra mussel is a small mollusk, native to Eurasia. A full-grown adult measures about an inch across. This destructive invader appeared in North America in the late 1980s. Discovered in Lake Texoma in 2009, it now infests several Texas lakes. Zebra mussels multiply rapidly and cause significant damage. They colonize docks and other structures, invade municipal water systems, disrupt the food chain that supports native fishes, and foul beaches with their sharp-edged shells.

Zebra mussels colony on native mussel shell One adult mussel, carried to a new water body on the bottom of a canoe, can produce up to a million microscopic larvae. They can survive for days in water trapped in a boat, so you could be giving them a ride without knowing it. Visit for more information on how you can help prevent the spread of this destructive pest.

Giant Salvinia

Closeup of giant salvinia plant Giant salvinia is a floating fern, native to Brazil, that has colonized waters in Louisiana and East Texas. It forms dense mats on the surface of lakes and slow-moving rivers, shading out native vegetation and using up dissolved oxygen that fish and other organisms need to survive. Infestations can also interfere with access to boat launches and fishing piers. A small fragment stuck to a boat or trailer can become a new plant in the next lake or river. A colony of giant salvinia can double in size within two weeks. Always check your boat and gear and remove any vegetation or mud before leaving a water body. More about giant salvinia.

More information on invasive species