SAN MARCOS—For decades, tourists flocked to the old Aquarena Springs amusement park to watch the swimming pigs and South Texas mermaids. To make sure they got a good look, the owners capped one of the springs and aimed its crystal-clear flow at a glass-walled "submarine."
The eyeless white salamanders that occasionally came shooting out of the pipe were a bonus. The "mermaids" would hold the salamanders up to the glass so those in the submarine theater could get a closer look.
"As I understand it, they put that diving bell and pipe over the spring to divert water into the show area to keep it clear," said Glenn Longley, director of the Edwards Aquifer Research and Data Center at Texas State University, which bought the amusement park in 1994 and turned into a preserve and learning center.
About a decade after the Texas blind salamander was placed on the federal endangered species list in 1967, Longley got a government permit to collect the salamanders. He put a net over the end of the 2-foot-diameter pipe to catch them.
He collected and handed over hundreds of the 5-inch-long salamanders to the U.S. Fish and Wildlife Service for a captive breeding program at the nearby San Marcos National Fish Hatchery.
But about three years ago, the number of salamanders snagged by the net began to decline. The old corrugated steel pipe, it turned out, was rusted through. Salamanders escaped into the San Marcos River, where they swam sightlessly into the jaws of bigger fish.
"One of my biologists mentioned the old rusty pipe in a meeting, and immediately several partners jumped in to make something happen," said Bob Pine, supervisor of the federal wildlife service's Austin office.
So over the next month, the old pipe will be replaced with a specially fabricated 11-foot-long high-density polyethylene pipe donated and delivered Friday by the San Antonio Water System at a cost of almost $15,000, said Patrick Shriver, a water resources planner for the utility.
The installation by a crew from American Underwater Services out of Fort Worth will take about five days.
Only about 40 percent of the water from what's called Diversion Spring goes through the pipe now because the spring has washed out around the concrete base below where the pipe connects, said Ron Coley, director of the renamed Aquarena Center.
When the new pipe is installed, the base will be fitted with a heavy polyethylene curtain that should capture most of the flow — and the salamanders.
Joe Fries, a federal fisheries biologist who has been working with rare Edwards Aquifer salamanders at the hatchery since 1996, said the captive wild population is down significantly since the pipe rusted out.
"We have about 20 wild stock now," he said. "We have around 50 offspring, and those basically are research animals. At one time we had over 200 wild stock, and then the pipe deteriorated so much that we weren't getting much. Hopefully, we'll get back up to several hundred, like we're supposed to have."
Fries said before the pipe started rusting out, Longley was delivering about 200 salamanders each year to the hatchery. About 100 more were dead by the time Longley retrieved them from the net, he said.
"The bad news is that about half of the ones we got didn't make it because it's a rough ride in there," Fries said. "You're basically shooting out of the ground and being plastered against a net by the pressure of the water, and you're talking about a little salamander."
The rare salamander — one of several known to live only in the Edwards Aquifer or its springs — spends its life in complete darkness underground in water-filled limestone caves near San Marcos — unless it gets too close to a natural spring.
Then the force of the water flow shoots the salamander out of the groundwater and into the river.
Fries said the goals of the captive breeding program are to keep the salamanders alive and have them reproduce.
"We have had reproduction in captivity, but it's been real sporadic, and we don't really have control at all," he said. "Ideally, what we want is to put a male and female together, have them reproduce and know who the parents are so we can control the genetics.
"Right now we have no control and the salamanders reproduce whenever they want to. The only thing we can really tell you is that you have to have a male and a female."
He said the oldest one in captivity is almost 9 years old.
"We still have a lot to learn from these little guys and we are all looking forward to seeing these critters come out of Diversion Springs again," said Carrie Thompson, a federal biologist.