The U.S. Fish and Wildlife Service has proposed adding two cavefish species that live exclusively in the Edwards Aquifer to the federal endangered species list in a move that aquifer officials say is premature.
The two fish, the toothless blindcat and widemouth blindcat, are tiny catfish species found in the artesian segment of the Edwards Aquifer, the vast underground reservoir that is the main water source for 2 million people in Central Texas, including San Antonio. Growing no larger than 6 inches, these fish are in danger of extinction due to groundwater pumping, said Michael Warriner, supervisory fish and wildlife biologist for the agency’s Austin Ecological Services Field Office.
“The toothless and widemouth blindcats are among the rarest fish species in the world and are found at the greatest subterranean depths known for cavefish, at over 1,000 feet below the city of San Antonio in the Edwards Aquifer,” he said. “While the great depth of their habitat protects them from many human-caused threats, thousands of these fishes were likely lost over the last one hundred or more years as groundwater pumping activity increased across Bexar County.”
The two species are among the smallest catfishes in Texas. Like other cave-adapted animals, they do not have any pigmentation or functioning eyes. The species typically live 40 to 50 years and have a slow rate of reproduction, Warriner said.
Since they are so small, the fish easily get sucked up through well pumps, he said. In fact, that was how the two species were first discovered; in the early 1900s, the fish were ejected from some of the first groundwater wells installed in San Antonio and Bexar County.
Because of the depth of their habitat — roughly 900 to 1,500 feet below ground — they do not survive ejection from the wells, Warriner said. They inhabit a very deep and little-studied region of the aquifer that is inaccessible to humans.
A long process
The crusade to get the blindcats on the federal endangered species list dates back to 2007, Warriner said, when the grassroots environmental nonprofit WildEarth Guardians petitioned for 100 species to be added to the list, including the two blindcats.
Their efforts slowly pushed the Austin Ecological Services Office into action, and in 2019 Warriner and his team began a species status assessment, which looks at how healthy a species is currently and considers how it might fare in the future.
The assessment, published in 2022, found both species — but especially the widemouth blindcat — could be in danger of extinction as a growing population taps aquifer water.
“With ongoing well pumping, we would project that both the toothless and widemouth blindcats will be reduced to such small numbers that these fishes will be at risk of extinction before 2100,” the assessment states. “Mortality to groundwater wells is the most impactful stressor that will continue affecting blindcats into the future.”
Environmental scientists are unsure of how many widemouth blindcats are even alive today, Warriner said. The last time a widemouth blindcat was collected from a well was in 1984, while a small number of the toothless blindcat were collected from a well as recently as 2022.
“Ninety-nine percent of the time the fish come out dead, and they don’t necessarily come out as a whole fish,” Warriner added. “They may come out as just tissues and bones.”
The proposed rule to list these species as endangered appeared in the Federal Register on Tuesday, and Fish and Wildlife is accepting public comments, submitted either electronically or by hard copy, through Oct. 23. Click here for more information on how to submit a comment.
The agency will evaluate the statements and information received during the comment period and will announce a final decision on whether to list these species as endangered within 12 months.
The EAA’s response
While the agency applauded the Edwards Aquifer Authority (EAA) for its efforts in protecting federally listed endangered species in a press release released Tuesday, an EAA official told the San Antonio Report in an emailed statement Tuesday that federally listing these two species as endangered now would be premature.
The EAA was created in 1993 as a result of a lawsuit filed by the Sierra Club against the agency that cited negligence to provide the necessary protection required by the Endangered Species Act. It is the authority that controls how much water is allowed to be pumped out of the aquifer.
Its permit holders must abide by EAA pumping restrictions, which exist to ensure minimum spring flows from the Edwards Aquifer-fed Comal and San Marcos springs to protect endangered species. Permit holders include the City of San Marcos; the City of New Braunfels; Texas State University; and the City of San Antonio acting by and through the San Antonio Water System.
Between 2008 and 2012, the EAA created the Edwards Aquifer Habitat Conservation Plan (EAHCP) and a funding plan, which were both launched in 2013. The EAHCP is a comprehensive, regional plan that defines how to protect federally endangered and threatened species that live in the Edwards Aquifer and the Comal and San Marcos Springs.
Species it seeks to protect include the Comal Springs fountain darter, Comal Springs dryopid beetle, Comal Springs riffle beetle, and Peck’s cave amphipod.
“We look forward to continuing to work collaboratively with the Edwards Aquifer Authority and other local organizations to conserve and protect the Edwards Aquifer for the benefit of people and wildlife,” said Karen Myers, field supervisor at the Austin Ecological Services Field Office.
EAA General Manager Roland Ruiz said the authority plans to submit a public comment stating they believe listing these two species on the federally endangered species list is premature.
“The best available science regarding the distribution, status and potential protection of both the toothless blindcat and the widemouth blindcat is extremely limited and, in our opinion, needs further study prior to determining whether listing them is appropriate,” Ruiz said. “We look forward to availing ourselves of the U.S. Fish and Wildlife Service’s public comment process to share our perspective.”
It is unclear how or if adding the fish to the endangered species would affect pumping from the aquifer.
Ruiz and the EAA declined to answer further questions about their statement.
