Striped bass began washing up on Canyon Lake’s shoreline and floating lifelessly near the dam and Boat Ramp #1 several weeks ago.
Texas Parks and Wildlife Department (TPWD) said there’s no cause for the alarm spreading on social media.
In an email to a Canyon Lake boat ‘Captain Steve,’ Patrick Ireland, a district biologist at TPWD’s Inland Fisheries office in San Marcos, described the rotting fish as a “natural, localized event, but definitely worth keeping an eye on.”
The dead fish are victims of an oxygen/temperature “squeeze” event similar to one that occurred in September 2024 — not debris fields or contaminants from July 4 flooding along the Guadalupe River, which enters Canyon Lake near Spring Branch.
Dissolved oxygen levels fell too low in August while water temperatures were too high, “squeezing” out available habitat for striped bass.
Ireland visited Canyon Lake Friday, Aug. 22 to document the fish kill and noted a “pretty good-sized” striped bass kill near the dam.
He counted 71 fish, all in the 18-22-inch range. Most looked fresh, with a few still struggling at the surface.
“From our measurements on Friday, dissolved oxygen dropped below 4 mg/L (milligram per liter) around 20 feet and went close to 1 below 30 feet,” he said in his email, widely shared on Facebook.
“Most freshwater fish, including striped bass, need dissolved oxygen to be at or above 5 mg/L. Water temperatures from the surface to at least 20 feet are very warm, likely getting too warm for striped bass.”
In its Aug. 20 fishing report, TPWD said bass fishing is showing signs of improvement in Canyon Lake, with some good catches reported.