For the past six years, the city has been making big strides to help preserve a tiny fish — and despite the appearance of parasites, it succeeding.
The fountain darter, which lives only in the Comal River and the San Marcos River, is an endangered species generally smaller than 3 centimeters, and feeds on even tinier invertebrates.
Placed on the endangered species list in the 1980s, the fountain darter’s habitat was considered threatened by decreasing water levels, according to records by the U.S. Fish and Wildlife Service.
These lower levels of water can be prime breeding grounds for fountain darter parasites, said Mark Enders, watershed program manager for the city.
Completed in 2012 and implemented in 2013, The Edwards Aquifer Habitat Conservation Plan is a cooperative effort to protect groundwater sources of the region to preserve the endangered species in the aquifer — including the fountain darter.
“When the EAHCP was developed, there was a concern about a gill parasite,” Enders said. “It’s a parasite that affixed to the gills of fountain darters, and there were worries about how it would affect fountain darter populations.”
The city of New Braunfels did research to evaluate the number of present parasites and their effects on fountain darters, Enders said.
“At the levels monitored, we aren’t seeing any significant effects,” Enders said.
Population counts of fountain darters, which have been ongoing for nearly 20 years, show no negative impacts from any parasite in either the Comal and San Marcos spring systems, according to information from the Edwards Aquifer Authority.
“We want to continue monitoring those populations, so when we get into times of low flow and the springs slow down we can make sure nothing is drastically changing,” Enders said.
Five permittees work together under the EAHCP, according to the city’s website; the City of New Braunfels, the San Antonio Water System, the City of San Marcos, Edwards Aquifer Authority and Texas State University.
Efforts to protect the fountain darter include both watershed protection and environmental programs, Enders said.
“Spring flow protection measures ensure the pumping of the Edwards Aquifer is limited to where it will provide the minimum spring flow needed to protect those species,” Enders said. “So that figure is 30 cubic feet per second — to achieve that there are several measures.”
One such measure makes it SAWS responsibility to keep an aquifer storage and recovery system that can help pump water into the area during times of drought, Enders said.
“There’s also the VISPO Program — an irrigation suspension program that pays enrolled permit holders, such as farmers, for not pumping during times of drought,” Enders said.
Efforts in the Comal River and Landa Lake include an aquatic vegetation restoration project, which came to be after initial research in 2013 showed invasive plant species were growing in Landa Lake.
“So we removed a lot of those from Landa Lake and the Comal River and went back and planted native plants that also work as habitat for the fountain darter,” Enders said.
Such plants include the ludwigia, sagittaria and more, Enders said.
“Long term monitoring is showing when you go out and sample how many fountain darters are in those plants, those plants that are native vegetation have higher numbers of fountain darters,” Enders said.
Every year, the EACHP has a projected amount of growth it wants met of each native plant in the rivers, Enders said.
Fountain darter populations are counted twice a year, in the spring and fall, Enders said.
“They do it more frequently if we got into low flow period,” Enders said. “In 2014, we got down to 65 cubic feet per second, so that was a time we monitored it more.”
Other methods that are helping the fountain darter population succeed are non-native fish monitoring — such as the underwater spear fishing of tilapia, nutria and sucker mouth catfish the city hires a contractor to perform — and maintenance of the rivers banks.
“Overall, we’ve been successful,” Enders said.
For more information about the fountain darter and efforts to protect it, visit https://www.nbtexas.org/1867/Habitat-Conservation-Plan.