Six Freshwater Mussel Species in Central Texas Listed as Endangered

Effective July 4, 2024, the U.S. Fish and Wildlife Service has listed six species of freshwater mussels in Central Texas as endangered resulting from climate change and urbanization. This decision has significant implications for water management and conservation efforts in the region.

The species listed as endangered are the Guadalupe fatmucket, Texas fatmucket, Guadalupe orb, Texas pimpleback, Balcones spike, and false spike. Additionally, the Texas fawnsfoot has been listed as threatened, meaning it is likely to become endangered in the future.

Freshwater mussels play a vital role in maintaining clean water systems by filtering harmful substances like algae and bacteria. A single mussel can filter between 8 and 15 gallons of water per day. They also stabilize sediment at the bottom of rivers, supporting biodiversity.

The decline of these mussel species is attributed to population growth, development, and climate change, which have led to changes in rainfall patterns and increased droughts. The construction of dams on rivers has further threatened their habitat by reducing water quality and hindering fish movement.

Why this matters: The listing of these mussel species as endangered has significant implications for water management and conservation efforts in the region. This decision could lead to federal oversight of aquatic habitats, potentially resulting in mandates to augment environmental flows in many streams and rivers in Central Texas.

The Fish and Wildlife Service has designated 1,577 miles of rivers and creeks in the Colorado, Guadalupe, Brazos, and Trinity river basins as critical habitat for the species. This designation bans development or projects that could harm the species and requires a federal permit or license.

Several water authorities in Texas, including the Brazos River Authority, Lower Colorado River Authority, Trinity River Authority, and Tarrant Regional Water District, have entered into voluntary conservation agreements to reduce threats to the species and improve water quality.

Amy Lueders, Southwest Regional Director of the U.S. Fish and Wildlife Service, emphasized the importance of these efforts, stating, "These unique freshwater mussels are found nowhere else in the world but in the rivers and streams of Central Texas... Saving these mussels isn't just about preserving the biodiversity of the region, it also helps protect the waterways that people rely on for water and recreation."

The listing of these mussel species as endangered will likely lead to federal oversight of aquatic habitats, potentially resulting in mandates to augment environmental flows in many streams and rivers in Central Texas. This could have long-term consequences for how much water cities, manufacturers, and farmers can pull from these rivers, affecting the water supply.

The Lower Colorado River Authority (LCRA) has already approved a 20-year agreement with the U.S. Fish and Wildlife Service to conserve four of the freshwater mussel species, which is expected to cost nearly $40 million over the next two decades. The LCRA is also working to address the issue of invasive zebra mussels that have invaded Central Texas waterways.

The designation of these mussel species as endangered highlights the need for continued conservation efforts and collaboration among local communities, river authorities, and federal agencies to protect and recover these imperiled species, ensuring the long-term conservation of these species.

Key Takeaways

• 6 freshwater mussel species in Central Texas listed as endangered due to climate change and urbanization.
• Freshwater mussels filter 8-15 gallons of water/day, supporting biodiversity and clean water systems.
• Listing has implications for water management, potentially leading to federal oversight and mandates.
• 1,577 miles of rivers and creeks designated as critical habitat, banning harmful development.
• Voluntary conservation agreements and federal permits required to protect the species and improve water quality.