Scientists from BIO-WEST Inc. count and analyze endangered aquatic species on Tuesday, April 26, 2022, near the headwaters of the San Marcos River in San Marcos.
In the middle of the San Marcos River, near Texas State University, four aquatic researchers are waist-deep in water, counting endangered little fish.
Led by aquatic ecologist Brad Littrell, they drop a weighted net — attached to a rigid, rectangular, 2-square-meter frame — into the river, and it sinks to the bottom. Then they use a smaller net to sweep for specific aquatic life.
Today, they seek the fountain darter, a tiny freshwater fish found in the San Marcos and Comal rivers. It’s one of many species that depend on the Edwards Aquifer for life and habitat, and for years, the U.S. Fish and Wildlife Service has listed it as endangered because of ongoing development and population growth.
Every fountain darter that they catch is put in a container of freshwater that will go to the reserve population at a center in San Marcos to protect the species from extinction.
One slips through Littrell’s fingers, but he catches it as it hits the net. He measures it in millimeters.
“Sixteen,” he calls out for a colleague to record.
Scientists from BIO-WEST Inc. count and analyze endangered aquatic species on Tuesday, April 26, 2022, near the headwaters of the San Marcos River in San Marcos.
A sign informs people that Texas wild-rice is protected in the San Marcos River.
An endangered fountain darter fish is displayed on Tuesday, April 26, 2022, as scientists from BIO-WEST Inc. survey endangered aquatic species near the headwaters of the San Marcos River.
Texas wild-rice grows under the water near Pyramid Park on the San Marcos River on Tuesday, April 26, 2022.
Littrell and his team are contractors from Bio-West, an environmental and planning consulting company in Texas hired by the Edwards Aquifer Authority for the agency’s Edwards Aquifer Habitat Conservation Plan. It’s been 10 years since the conservation plan was devised to rehabilitate the San Marcos and Comal rivers and protect the endangered plants and animals in it.
Since then, the aquifer authority has restored some balance in the river, reducing murky sediments and removing invasive species. Counting and collecting endangered animals, such as the fountain darter, is one way to examine trends and protect species in the future — one fish at a time.
“We’ve seen a lot of change here,” said Kristy Kollaus, an environmental scientist with the conservation plan. “But we’re still working at it.”
Throughout the San Marcos River, Zizania texana — more commonly known as Texas wild rice — has grown extensively for the past decade.
The species is rare, having been found only in the upper San Marcos River in Hays County. Before the introduction of the Edwards Aquifer Habitat Conservation Plan, this kind of wild rice was overrun by invasive plant species, which kept the native plant from growing at its normal rate and surviving in its natural habitat.
Texas wild-rice is seen near the headwaters of the San Marcos River on Tuesday, April 26, 2022.
However, from 2013 to 2018, the wild rice experienced a nearly 200 percent increase in coverage, springing up in the river and protected from harvesting in accordance with the conservation plan, Kollaus said.
“What used to be a mix of nonnative plants is now long stretches of wild rice,” she said. “We have the area listed as a state scientific area, which makes it illegal to uproot or trample Texas wild rice.”
One way the conservation team improved the wild rice’s habitat was to strengthen the sides of the river to prevent erosion and sediment from falling into the water. Such sediment clouds the water, keeping the wild rice plants from absorbing sunlight, which they need for healthy growth.
Large landscaping stones known as butter blocks were installed at certain areas to keep the sediment at bay and to create access points for recreational swimming. So far, seven access points have been built under the conservation plan, and the tactic has resulted in clear water for photosynthesis. The butter blocks also prevent the suckermouth armored catfish, which is an invasive species, from burrowing into the banks, which increases erosion.
Meanwhile, the aquifer authority strongly advises that people who swim in the San Marcos River — an activity that will increase as temperatures rise — use these created access points and avoid fenced-off areas. Doing so will help minimize erosion and muddy waters.
“We’re not entirely sure what this area looked like before development since that first started happening in the mid-1800s,” Kollaus said. “But we do know we can rehabilitate it to a point where we are getting rid of the invasive species and letting the native plants make a comeback.”
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From left, BIO-WEST Inc. scientists Chance Boatright, Cara Wade, Brad Littrell and Kyle Sullivan count and analyze endangered aquatic species on Tuesday, April 26, 2022, near the headwaters of the San Marcos River in San Marcos.
Brad Littrell, center, an aquatic ecologist at BIO-WEST Inc., directs a count of endangered aquatic species on Tuesday, April 26, 2022, near the headwaters of the San Marcos River in San Marcos with co-workers Kyle Sullivan, left, and Chance Boatright.
Scientists from BIO-WEST Inc. count and analyze endangered aquatic species on Tuesday, April 26, 2022, near the headwaters of the San Marcos River in San Marcos.
Scientists from BIO-WEST Inc. count and analyze endangered aquatic species on Tuesday, April 26, 2022, near the headwaters of the San Marcos River in San Marcos.
Scientists from BIO-WEST Inc. stand near stalks of Texas wild-rice as they count and analyze endangered aquatic species near the headwaters of the San Marcos River in San Marcos on Tuesday, April 26, 2022.
Texas wild-rice grows near Pyramid Park on the San Marcos River on Tuesday, April 26, 2022.
Texas wild-rice grows near Pyramid Park on the San Marcos River on Tuesday, April 26, 2022.
Texas wild-rice grows under the water near Pyramid Park on the San Marcos River on Tuesday, April 26, 2022.
A sign informs people that Texas wild-rice is protected in the San Marcos River.
Kristy Kollaus, an environmental scientist with the Edwards Aquifer Authority, talks on Tuesday, April 26, 2022, about efforts to stabilize the banks of the San Marcos River as part of the Edwards Aquifer Habitat Conservation Plan.
An endangered fountain darter fish is displayed on Tuesday, April 26, 2022, as scientists from BIO-WEST Inc. survey endangered aquatic species near the headwaters of the San Marcos River.
An endangered fountain darter fish is displayed on Tuesday, April 26, 2022, as scientists from BIO-WEST Inc. survey endangered aquatic species near the headwaters of the San Marcos River.
A fresh water shrimp is displayed on Tuesday, April 26, 2022, as scientists from BIO-WEST Inc. survey endangered aquatic species near the headwaters of the San Marcos River.
A crawfish is displayed on Tuesday, April 26, 2022, as scientists from BIO-WEST Inc. survey endangered aquatic species near the headwaters of the San Marcos River.
Two gar fish swim in the waters just below Spring Lake dam near the headwaters of the San Marcos River on Tuesday, April 26, 2022.
The San Marcos River flows below the Spring Lake dam near the headwaters of the river in San Marcos on Tuesday, April 26, 2022.
Littrell and the team from Bio-West sweep their smaller net 15 times over the drop net area in the river. After about two hours in the morning, they had caught several fountain darters, putting each one in their bucket. And with a cooler of snacks in their boat, they planned to continue counting fountain darters until about 5 p.m.
Before they ventured into the river, a team surveyor mapped the area, identified the different types of habitats there and randomly pinpointed locations to drop nets. It all helps the team better understand how the fountain darters are doing.
“We want to monitor that what we’re doing with invasive and native plants is not negatively impacting the river species,” Kollaus said. “We can track and follow the trends and then make changes if we see something that doesn’t look right and minimize the impact.”
So far, the fountain darter population hasn’t changed much. The river is a dynamic system, Littrell said, and conditions appear fairly stable. At the same time, it can be hard to detect changes.
“It’s some noisy data,” he said.
Contractors are also counting the Texas blind salamander at the river and at Spring Lake, in some cases diving with scuba equipment to collect aquatic life.
For the trip to the river, Sarah Valdez, senior STEAM outreach educator at the Edwards Aquifer Authority, brought two coolers to collect native and nonnative species for the agency’s new education center. It wants to include endangered species eventually, which requires obtaining a permit.
The hope is to make this last decade of conservation work — such as with the fountain darter and the Texas wild rice — more understandable. The various species will be taken to the education center and displayed with infographics and other explainers regarding their habitats.
“It’ll be exciting to really see what’s there,” Valdez said, “and what we can learn from it.”
Elena Bruess writes for the Express-News through Report for America, a national service program that places journalists in local newsrooms. ReportforAmerica.org. elena.bruess@express-news.net
Elena Bruess joined the Express-News as the environment and water reporter in June 2021 through Report for America. Previously, she covered water issues for Circle of Blue in Michigan and wrote about COVID-19 in Chicago as a reporting fellow for the Pulitzer Center. She has a master's in science journalism from Northwestern University and a degree from the University of Iowa's undergraduate writing program. She is originally from northeastern Iowa, but also grew up in central Greece.