A red crescent moon hung over the horizon as I pulled up near Rio Vista Park, in San Marcos, just before six on a February morning. My car’s thermometer read 45 degrees. The park includes a short stretch of the San Marcos River, which is spring fed and thus stays at a constant 72 degrees. Though that would be pleasant as an air temperature, it means snorkeling in a wet suit with neoprene gloves, booties, and a hood. After I suited up, only my face was exposed.
A hulking SUV pulled into the spot next to me, and bounding out of it, already zipped into his wet suit, came Nick Menchaca, the 35-year-old founder and owner of Atlas Environmental, a San Marcos–based business that works with the city to remove invasive fish species from the Comal and San Marcos rivers. “Should be pretty rad, man!” he said as he greeted me. Menchaca looks more like someone you’d expect to find leading a circle discussion about chakras than wearing camo and clutching a couple of three-pronged spears, which we’d use to hunt one of the most significant threats to the river’s ecosystem: suckermouth armored catfish.
We were meeting at this unholy hour so he could give me a tutorial ahead of my participation in Atlas Environmental’s semiannual polespear tournament, held every February and November. Participants compete over a two-week period to skewer invasive fish (tilapia have also arrived in the river, but they’re not nearly as numerous as armored catfish) with a polespear—a five-foot-long rod with three pronged and barbed tips. Using it is simple: just loop the thick rubber band that’s attached to the handle between your thumb and index finger and grip the spear near the business end so that the band is taut, point at your target, and release your grip, which sends the pole shooting forward with surprising velocity.
The tournament, which began in 2014, draws about sixty spearers. Participants are credited with removing about 3,500 pounds of armored catfish and 450 pounds or so of tilapia in that ten-year period. Menchaca has been hunting these menaces since 2013, and he spears year-round, except during the tournaments. He estimates that Atlas Environmental has removed 30,000 pounds’ worth from the San Marcos and Comal rivers and springs.
That sounded unbelievable to me, but I would soon wonder if he was being modest.
After a few rounds of grip and release in the parking lot, I followed Menchaca into the river. I had barely started swimming when he signaled to me with his flashlight.
“Here’s one,” he called out after popping his snorkel out of his mouth. “See if you can get it, man.”
I started kicking over to him and suddenly, out of the darkness, a catfish darted straight at my flashlight’s beam before ducking down and coming to rest on the river floor below me. Its gills were pulsing, and its spiny dorsal fin flared up. I kept my light fixed on it as I carefully aimed my spear. I released my grip and felt the handle slide violently through my hand. The prongs struck the fish with enough force that they went through its body and hit the rocks beneath it with a clink. The suckermouth was still squirming as I held it up over the water. Menchaca let out a whoop and took the weapon from me. “Next time, push the spear down into the bottom. Really get it in there,” he advised as he dipped it back into the water and pinned the struggling catch against the riverbed. “This is a big one,” he said, pulling the now motionless creature off the tips and shoving it into the bag. “That was your first time spearing? Man, I’m gonna play the lotto today!”
We hunted for about half an hour, and at regular intervals I would hear Menchaca’s spear tips hitting stone. I caught one more that was hiding under a boulder. “Dude, two for two!” Menchaca said after he added my catch to the bag, now bulging with other dead and dying catfish. In less than twenty minutes, he had caught twelve. I felt exhilarated by my modest contribution, but I remembered I wouldn’t have Menchaca to guide me at the tournament. That we’d found so many in such a small area made me confident—but also worried that the war against the invasives was already lost.
If you are what you eat, then the suckermouth armored catfish deserves its ugly looks. “They’re basically consuming algae and detritus that’s accumulating on the riverbed,” said Christopher Riggins, a wildlife and fisheries biologist at Texas State University’s Meadows Center for Water and the Environment. “Detritus” is the scientific term for decomposing organic matter, including plants, sea critters, and, well, fish poop. “That’s why you buy them for your fish tank—to keep it clean,” he told me.
And the first invaders almost certainly came from those home tanks decades ago. “People buy a catfish but don’t realize it can grow as long as fifteen inches. The fish outgrow the tank, and the owners don’t want to deal with it, so they just dump it in the local river,” Riggins said. Now the fish are so numerous that Riggins and researchers at Texas A&M University and Texas Parks and Wildlife are working to get a more accurate count.
While a horde of enthusiastic waste eaters vacuuming the river might seem like a good thing, it threatens native species such as the tiny endangered fountain darter, which lays its eggs on the same algae that the catfish gobble up. But Riggins, who participates in the Atlas Environmental tournament, said measuring the damage is secondary to the immediate task at hand. “There’s enough of an impact that we should skip that part and go right to how do we get rid of them as quickly as possible,” he said.
Spearfishing, a niche sport and one of the most ancient forms of hunting, is for now the most effective, environmentally friendly way of removing armored catfish. A study coauthored by Texas A&M researchers and Menchaca found that the practice increased catfish mortality by 50 to 75 percent. “That’s effective enough to cause significant suppression but not enough to completely eradicate them,” Riggins said. A single female catfish can lay more than three hundred eggs at one time, which can hatch in a matter of days.
Spearing can’t keep up with that fast a reproduction rate. Researchers are exploring the solution of breeding and releasing “supermales”—fish with two Y chromosomes, which guarantee that their offspring will also be male. Over time, too many males and not enough females should lead to a population collapse. The method is currently being used against the brook trout, which has invaded rivers in the western U.S. But scientists here are only in the early stages of studying its feasibility.
“That’s something we’re looking to do over the next three to five years,” Riggins said. Spearing, for now, remains the best way to wage battle.
My spearfishing success turned out to be beginner’s luck. The only thing I caught during the tournament was a case of the heebie-jeebies. At one point I found myself in a particularly deep part of the river late at night when a monstrous fish materialized out of the darkness, roughly four and a half feet long with big yellow eyes, a long snout, and a row of small, sharp teeth. It was an alligator gar, which feeds on smaller fish, including catfish. But despite it being the enemy of my enemy, I wasn’t quite ready to call it a friend.
A couple of weeks later I attended the end-of-tournament fish fry that Menchaca hosts on the lawn outside Ivar’s River Pub, just across from Rio Vista. He and several volunteers handed out tacos with meat from tilapia captured by the event’s participants. (Suckermouth meat can be eaten, but for the most part Atlas Environmental composts them.) Over the course of sixteen days, spearfishers had removed 443 armored catfish and 29 tilapia.
Menchaca reassured me that first-timers often come up empty. Despite my failure, I had discovered a new adventure sport, one that I’ll try again—for the sake of both my ego and the San Marcos River.
This article originally appeared in the October 2024 issue of Texas Monthly with the headline “Stalking the Suckermouth.” Subscribe today.
