Protection of two Central Texas mussels secured with U.S. Fish and Wildlife Service agreement

Balcones Spike

The future of two Central Texas mussels is more secure thanks to a partnership between the Brazos River Authority and the U.S. Fish and Wildlife Service. The agreement allows the organizations to take steps to proactively protect the Balcones Spike and Texas Fawnsfoot mussels from possible extinction.

There are more than 50 mussel species in Texas. Each plays an important role in our waterways, making their protection essential to all living within the Brazos River basin.

In 2016, the USFWS began evaluating six freshwater mussels known to occur in the Guadalupe, Colorado, and Brazos rivers to determine if the species’ status warrants federal protection under the Endangered Species Act. Two of the six freshwater mussels live in the Brazos River basin, the Truncilla macrodon, known as the Texas fawnsfoot, and the Fusconaia iheringi, known as the Balcones spike. The purpose of the Endangered Species Act is to protect and recover imperiled species and the ecosystems they depend on, according to the USFWS.

Categories were established in 1973 by the U.S. Congress through the Endangered Species Act to protect plants, animals and insects, allowing them and their ecosystem time to recover. The federal law created three main categories where a species in danger may be placed: threatened, endangered, and candidate.

Recently, the USFWS published its decision to protect the Balcones Spike and Texas Fawnsfoot under the Endangered Species Act. While this decision is not yet final and is open for public comment, listing either species can have significant implications for current and future water supply operations and other activities in rivers in the basin occupied by the two species.

Recognizing the perilous status of both species and the potential effect their loss would have on the Brazos River basin, the BRA entered into discussions in 2018 with the USFWS to perform voluntary conservation for both species. Bi-valve aquatics, such as these to mussels, help to naturally clean surface water, reducing turbidity. The presence of diverse and reproducing populations of mussels also indicates a healthy aquatic system, which means good fishing and water quality.

The reason these two freshwater mussels are facing extinction is due to alterations to their habitats caused by dams, decreased flows from surface water and groundwater use, flood events that lead to scouring of riverbeds, water quality degradation, excessive sedimentation from erosion, and population isolation created by dams and low-water crossings, according to the report.

After three years of negotiation, in June 2021, BRA’s General Manager and Chief Executive Officer David Collinsworth executed the BRA’s first Candidate Conservation Agreement with Assurances with the USFWS. In this agreement, the BRA commits to implement a voluntary conservation strategy for the Balcones Spike and Texas Fawnsfoot.

“The Candidate Conservation Agreement with Assurances is a groundbreaking agreement, as it is the first system-wide conservation partnership designed to protect the diversity of aquatic species in the Brazos River basin,” Collinsworth said. “By entering into a partnership with the USFWS, BRA demonstrates its commitment to responsibly developing the water resources of the Brazos River basin needed to support not only the economy and people of the state of Texas but also to support the state’s natural resources.”

The Texas Fawnsfoot has been found in multiple locations within the Brazos River basin, including the Clear Fork of the Brazos River, the Brazos River between Possum Kingdom Lake and Lake Granbury, the Brazos River below Waco and the Navasota River and the Little River. Within the Brazos River basin, the Balcones Spike is currently known to reside in the Little River, San Gabriel River, and Brushy Creek.

This groundbreaking agreement will benefit other aquatic species.

Part of the conservation strategy of the agreement includes research and monitoring to further our knowledge of the species. The agreement provides for the protection of existing populations, education and public outreach activities, development of Drought Contingency Plans for the mussels, and employs both collaborative conservation and adaptive management principles. It also includes the development of conservation zones, and future water-use modeling makes these conservation measures a priority, reducing current and future threats to the species.


Protecting the freshwater mussels is part of the BRA’s strategic plan to protect water resources, and where possible, improve water quality and habitat to support responsible and efficient use of the Brazos River basin’s natural resources

As part of the agreement, the USFWS will issue the BRA an Enhancement of Survival Permit, or ESA Section 10(a)(1)(A), authorizing the incidental take of the species as long as BRA’s actions are consistent with the CCAA. The permit then provides the BRA with regulatory assurance from USFWS that they will require no additional conservation measures from BRA should the species be elevated to threatened or endangered status.

Once finalized, the BRA will move from monitoring three candidate species to two in the Brazos River basin: the Western Chicken Turtle, the Texas Fawnsfoot, and the Balcones Spike.

By Tiffany Malzahn
Environmental and Compliance Manager for the Brazos River Authority.