Does it surprise you that these animals are considered invasive?

Does it surprise you that these animals are considered invasive?

Invasive animals can negatively impact your community, health, and pocketbook.

Zebra Mussels

Their presence affects us all. Knowing what they are and what you can do will go a long way in helping prevent economic and ecological damage and impact to human health.

Invasive animals are simply animals not native to a particular area.

These animals can take over ecosystems, spread rapidly, and decrease the biodiversity of native plants and animals. They can have a devastating effect on the natural resources of the state. They have few natural predators, competitors, or diseases to control their populations. Also, native wildlife may not have evolved defenses against them or be able to compete with a species without predators.

Often unintentionally, invasive species are primarily spread by human activities. Boats may carry them on their propellers, plants can escape into the wild, or some invasive species are intentionally or accidentally released pets.

Unfortunately, prevention, detection, monitoring, and repairing the damage caused by invasive species is extremely expensive. The nationwide annual economic impact of invasive species on the state exceeds $120 billion, according to the Texas Parks and Wildlife Department. Fishing and hunting opportunities, property values, water recreation, and water quality can all be impacted by invasive species.

These headaches have also made their home in the Brazos River basin.

Three particular animals rank among the most common invasive animals in Texas and the Brazos River basin: zebra mussels, feral hogs, and nutria.

The Brazos River Authority’s Environmental Services Department regularly monitors different animals to track the health of the basin’s ecosystem. When monitoring results show changes, the BRA, along with state and federal partners, work together to identify the cause and make improvements to aid the continued health and quality of the basin’s water supply.

Zebra Mussels

They are the size of a dime, but have caused alarming declines in fish populations, birds, and native mussel species and can disrupt a water supply system by colonizing the insides of pipelines and restricting waterflow, according to TexasInvasives.org, a partnership of state and federal agencies, conservation organizations, green industry, academia, and other private and public stakeholders. Millions of dollars are spent each year controlling, cleaning, and monitoring zebra mussels in other states, according to TexasInvasives.org.

As of August 2022, 30 Texas lakes across five river basins are infested with zebra mussels, which means the water body has an established reproducing population. The infested lakes within the Brazos River basin include: lakes Georgetown, Granger, and Stillhouse Hollow. 

The Texas Parks and Wildlife Department and its 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 are encouraged to 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 aquaticinvasives@tpwd.texas.gov.

Visiting a lake soon? There are easy steps to make sure your watercraft doesn’t transfer zebra mussels.

  • Clean: Inspect your watercraft, trailer and gear. Remove all plant material and mud.
  • Drain: Remove all water from the boat, as well as the motor, bilge, live wells and bait buckets.
  • Dry: Open all compartments and allow the boat and trailer to dry for at least a week or more before going into another body of water. If the boat cannot be dried for a week, it is recommended that the boat be washed with high pressure and soapy water.


Often mistaken for a beaver, Nutria weighs up to 22 pounds and live up to 10 years. They can swim underwater and are agile on land. With large front teeth that are often yellow or brown, Nutria are, in fact, a large form of rodent.


The animals with yellow or orange teeth have a relatively high reproductive rate combined with a lack of population controls have resulted in a proliferation of the species, according to the Texas A&M AgriLife Extension Office.

Nutria have damaged agricultural crops and infrastructure and carry several pathogens and parasites that can be transmitted to humans, livestock, and pets, according to the U.S. Fish and Wildlife Service.

There are some techniques to manage the invasive animal if you come across them. The Texas A&M AgriLife Extension Office has information here.

Feral Hogs

If you know them, there’s a good chance you already dislike them.

Feral hogs negatively impact agriculture by trampling, consuming, and digging up massive amounts of planted crops. They are extremely destructive. 

Feral Hogs

In the United States, they number more than 6 million and are found in at least 38 states or territories, according to the U.S. Fish and Wildlife Service. Currently, they are found in every Texas county, except El Paso, according to TexasInvasives.org. They prey on ground-nesting birds, amphibians, reptiles, and other wildlife and can carry at least 30 viral and bacterial diseases

TexasInvasives.org also has an online reporting tool for anyone who has found a feral hog.

How You Can Help

Here are a few ways you can help with the fight against invasive species, per the US Fish and Wildlife Service:

•    Don’t release unwanted pets or dump the contents of an unwanted aquarium into the wild.
•    Clean and drain your boat and gear before leaving a site.
•    Plant native bushes, flowers, and grasses in gardens to encourage biodiversity. Whenever possible, use only native plants that are appropriate for your region.

Learn more about species in the Brazos River basin here.