SAN MARCOS, Texas (KXAN) — One of Central Texas’ most popular recreation destinations is in danger. An invasive fish, the Suckermouth Armored Catfish (or Plecostomus), entered the San Marcos River in the 1970s and has spent the last five decades destroying popular spots along the river.

This month, the city has been hard at work repairing erosion at the Rio Vista Falls. Part of this erosion has been caused by this invasive fish burrowing into the ground beneath the manmade structures surrounding the falls.

A research team removes Suckermouth Armored Catfish from beneath the Rio Vista Falls (Courtesy: Texas State)

“They can basically spawn year-round and get out of control pretty quick,” said Christopher Riggins, an aquatic biologist with the Meadow Center for Water and the Environment at Texas State University. He’s part of a team working to study the fish in hope of eliminating them from the river.

“Species like Plecostomus can actually cause extra erosion and damage to those manmade structured areas that are there for recreation,” Riggins said. “We’re learning how much damage (they) can cause and the need to remove them.”

Last week, Riggins’ team, which includes researchers from Texas A&M and Texas Parks and Wildlife, who fund the project, took advantage of the repairs to Rio Vista Falls. With the water drained, they were able to remove more than 400 fish from the river.

The researchers will study the genders of the fish they removed. They hope to learn which are male and which are female so they could perhaps introduce sterile male Plecostomus into the river. It’s a population-curbing technique that has worked in the past for other invasive species.

Riggins’ team will also tag the fish later this year. This will help them track their movement patterns and figure out where they’re hiding.

Hunting Suckermouth Armored Catfish

More than 400 Suckermouth Armored Catfish were removed from beneath Rio Vista Falls (Courtesy: Texas State)

The Plecostomus was introduced into the river in the 1970s by aquarium owners. The fish was purchased by people looking for freshwater fish, and they can grow over a foot long. Riggins says he has seen people dumping aquariums into the river recently, introducing other invasive fish into the river.

About a decade ago, the City of San Marcos started taking steps to remove the fish from the river. They began hiring environmental contractors to hunt down the fish.

Riggins works with one of the contractors, Atlas Environmental. Since 2013, Atlas Environmental has removed more than eleven thousand Plecostomus from the river.

They remove the fish a few different ways: spear-fishing tournaments, community events like cook-offs and an ongoing bounty on the fish’s head. Spear-fishing the Plecostomus is challenging because the fish can burrow beneath man-made structures where rapids are intense.