Fish kills reported near Lake Corpus Christi as water from recent floods continues flowing downstream

Texas Parks and Wildlife says low oxygen levels caused by flood runoff is behind fish kills reported near Lake Corpus Christi. Officials are looking to investigate.

CORPUS CHRISTI, Texas — The return of water to Lake Corpus Christi has been a welcome sight after years of drought, but residents are now witnessing an unfortunate side effect.

Dozens of dead fish have been reported along portions of the Nueces River and near Lake Corpus Christi, including the Lagarto Lagoon, as wildlife officials investigate what is causing the fish kills.

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Longtime Lagarto resident Conrad Conrad said he first noticed the dead fish after stepping onto his dock.

“This is terrible, absolutely terrible,” Conrad said.

He said it was the first time he had seen dead fish in the lagoon.

“We’ve never had dead fish. Wow, wow,” Conrad said.

Conrad said the change happened quickly as rising water from Lake Corpus Christi reached the lagoon.

“Even though we’ve had the water come in the last couple of days, an awful lot of fish followed it in, really surprising. By Sunday there were fish jumping all over out there. By Monday afternoon they were all dead,” Conrad said.

Trying to understand what happened, Conrad began looking for answers.

“It just boiled down to lack of oxygen for the fish because they. I was out there Sunday night and the water was relatively clear, everything looked good. Monday morning, the water was brownish red, visibility was about one foot,” Conrad said.

Texas Parks and Wildlife Department officials say recent flooding is contributing to conditions that can lead to fish kills.

Alex Nuñez, regional response coordinator for the department’s Kills and Spills Team, said floodwaters from the Texas Hill Country have carried large amounts of organic material downstream.

“During this flooding we’re seeing a lot of runoff and a lot of organic material going into these rivers. As the rivers flow into these lakes, they’re discharging a lot of that organic material along with the increased water flow,” Nuñez said.

As that organic material decomposes, it consumes oxygen in the water.

“This low dissolved oxygen event is what’s causing the fish kills. Basically, there’s no oxygen for the fish to breathe, and over time they start, we start having this die off,” Nuñez said.

Although the flooding in the Hill Country has ended, water continues moving downstream through the river system.

Nuñez said it needs to run its natural course, and water quality should begin improving once flows return to more typical conditions.

“Once that pulse is done, and returns back to just base flows, then I think that’s when we’ll start to see the recovery of the water quality in the lake itself,” Nuñez said.

Nuñez said Texas Parks and Wildlife recently responded to a similar event at Choke Canyon Reservoir. He said the agency is now coordinating with a team in Mathis to investigate the fish kills near Lake Corpus Christi and collect water samples to better understand the conditions that caused them.