Daniel Pearson of the USGS (left) and Timothy Bonner (right) survey the Delaware River. Credit: Colin McDonald / Texas Comptroller's Office

A team of scientists from Texas State University is taking on a $2.3 million project to research several species of freshwater mussels found in the Guadalupe, Brazos, and Colorado rivers, the Texas Comptroller’s office announced Tuesday.

The research project, underwritten by funds granted by Texas Comptroller Glenn Hegar, will aid the U.S. Fish and Wildlife Service (FWS) in determining whether the bivalves should be put on the federal endangered species list. This in turn could involve special habitat protections that could affect statewide water distribution from Texas rivers.

Because of the potential impact on the state’s vulnerable water resources, the Comptroller’s office hopes that the mussels study – expected to be the most comprehensive of its kind in the Southwest region – will allow FWS to make a sound decision about whether the mussels should be placed on the endangered list.

The FWS expects to make its listing decisions by September 2018.

“Water is a very valuable resource and one that Texas has spent quite a bit of time trying to protect. The potential consequences [of the listing] could be very severe,” said Robert Gulley, director of economic growth and endangered species management for the Comptroller’s office. “We don’t have a particular outcome in mind, but it’s important that the decisions are based on good science, and that’s the hallmark of what we’re trying to achieve.”

As part of the research effort, Gulley said, the Comptroller’s office will work with FWS to engage stakeholders that may be affected by a potential endangered designation, such as river authorities, as well as developers, landowners, and ranchers who believe the regulatory limitations brought on by the designation would hurt their businesses and the overall Texas economy.

“This partnership will address voluntary conservation measures that, if needed, will protect the mussels while minimizing potential impacts to our state’s economy,” Hegar stated in a news release. “Our office believes a science-driven, open and transparent stakeholder process will lead to a collaborative solution for issues concerning the Central Texas mussel.”

Researchers will study five species of Central Texas freshwater mussels – the False Spike, Smooth Pimpleback, Texas Fatmucket, Texas Fawnsfoot, and the Texas Pimpleback – to learn more about the animals, their needs, and what humans can do to protect and restore them.

A Smooth pimpleback mussel.
A Smooth Pimpleback mussel. Credit: Courtesy / Timothy Bonner

FWS had previously identified these species as “sufficiently at risk,” Gulley said, which could mean a variety of things: their numbers could have appeared to decline or their habitat could have been destroyed, for example.

Scientists from Texas State plan to determine why the mussels were labeled “sufficiently at risk” and fill key data gaps in determining their need for protection. Eventually, they could create a program to protect the species.

“The problem is that so little is known about them,” said Colin McDonald, policy analyst for economic growth and endangered species management at the Comptroller’s office. Right now, McDonald said, researchers know that the number of mussels in river basins has declined, but they don’t know why.

“To protect them, you first have to understand them,” he said, “so that’s what we’re trying to do now.”

The research will involve studying and recording the numbers and distribution of mussel species and understanding the potential environmental impacts on the mussels, such as water flow or water levels, Gulley said.

Texas State scientists will collaborate with scientists at the San Marcos Aquatic Research Center and the Inks Dam and Uvalde national fish hatcheries for captive propagation, or breeding of the mussels in hatcheries to increase their population and eventually reintroduce them into their natural habitat.

Texas State University students and staff Chris Vaughn, Mike Parham, Timothy Bonner, and Dave Ruppel survey a Texas river.
Texas State University students and staff Chris Vaughn, Mike Parham, Timothy Bonner, and Dave Ruppel survey a Texas river. Credit: Courtesy / Texas State University

“The U.S. Fish and Wildlife Service applauds the Texas Comptroller’s office for taking a proactive partnership approach to mussel research and voluntary conservation,” stated Benjamin N. Tuggle, FWS southwest regional director, in a news release. “As we move forward, we must have contemporary science available to us in order to develop collaborative approaches for the conservation of these aquatic species.”

Led by Texas State biology professor Timothy Bonner, the team of researchers plans to survey the river basins this month, which means counting the animals and observing their conditions, Gulley said. But cold weather, which causes the mussels to burrow deep into the soil, could delay these efforts.

Scientists will survey the Colorado River, the Brazos River – which extends from the coast all the way up into the Panhandle – and the upper reach of the Guadalupe River, using divers in waters too deep for snorkeling. The lower reach of the Guadalupe, Gulley said, has already been extensively surveyed by the Texas Parks and Wildlife Department.

In 2013, the Texas Legislature appropriated $5 million to the Comptroller’s office to contract with state universities to provide in-depth research on species considered for endangered status. In 2015, the Legislature tacked on an additional $5 million for this purpose, which is now funding the freshwater mussels research.

The effort is not unlike one that occurred in the 1990s, when endangered species were found in the Edward’s Aquifer. The Sierra Club filed a federal lawsuit against the U.S. Fish and Wildlife Service for failing to enact aquifer pumping limits that would help prevent reduced spring flow in the Comal River and San Marcos Springs. Diminished flow could potentially kill the endangered species that depend on those springs.

This ultimately led to the formation of the Edwards Aquifer Authority in 1993, and later the Recovery Implementation Program for the Edwards Aquifer region, which “identified and evaluated methods to protect threatened and endangered species associated with the Edwards Aquifer,” its website states.

Gulley, a San Antonio native, played a key role in forming the Recovery Implementation Program by helping coordinate among numerous stakeholder groups and the San Antonio Water System to reach an agreement.

“We have the same set of variables [in the mussels research],” McDonald said. “There are species dependent on water quality and the quantity of the Guadalupe, Colorado, and Brazos rivers, and a lot of people also need that water.”

Gulley has high hopes for the evidence the mussels study will provide to stakeholders, and that it will dictate the successful future of Texas’ rivers and its natural inhabitants.

“We’ve got a good group [of researchers],” he said, “and a research plan well designed with good science to carry it out.”

Camille Garcia

Camille Garcia is a journalist born and raised in San Antonio. She formerly worked at the San Antonio Report as assistant editor and reporter. Her email is camillenicgarcia@gmail.com