Summertime Fish Kills Affecting Lakes

From Texas Parks & Wildlife Department

Fort Worth— As daytime temperatures remain above 100 degrees, Texas Parks and Wildlife Department (TPWD) Inland Fisheries biologist are getting more calls from concerned anglers and pond owners in the Dallas-Fort Worth Metroplex regarding fish kills.

“Unless the weather pattern changes in the near future, we expect to see more issues with fish kills as August rolls in,” said TPWD Inland Fisheries biologist Tom Hungerford.

A fish kill has been reported recently at Kimzey Park in Colleyville, which is likely attributable to a combination of low oxygen as well as a blue-green algae bloom. Blue-green algae produce toxins which can kill fish. Also, an ongoing fish kill is occurring at Lake Ray Hubbard involving blue and channel catfish and freshwater drum. “Monday, July 25, we estimated 2,071 dead fish based on three transect counts between the dam and IH-30,” said Melissa Dudley, a Kills and Spills biologist with TPWD. Low oxygen is suspected but the investigation is ongoing.

Water is a very interesting medium: As the temperature increases, the solubility of gases (specifically oxygen) decreases. With this in mind, fish are more likely to die of low oxygen stress when water temperatures are elevated because less dissolved oxygen is held in warm water and the fish’s metabolic requirements for oxygen are increased as temperature increases.

With record high low temperatures coming in recent weeks, surface water temperatures are reaching new heights. Small ponds are getting into the mid-90s while larger reservoirs are pushing 90 degrees. Also, the drought is lowering lake levels. Without sufficient rainfall, boating access may become impacted by low water.

Boaters and anglers are urged to use caution when on the water. Stay hydrated, wear a PFD at all times and carry a cell phone in case of an emergency.