Golden alga causes fish kill at Altus City Lake

Fisheries biologists have corralled a golden alga bloom at Altus City Lake ­ at least for now. A toxic bloom of the alga killed thousands of fish recently in a 22-acre portion of the southwestern Oklahoma municipal lake.

“Fortunately, the area was small enough and we were able to treat it and keep the golden alga from spreading and killing even more fish,” said Larry Cofer, southwest region fisheries supervisor for the Wildlife Department.

Golden alga has caused massive fish kills on Texas lakes in recent years and a minor fish kill on Lake Texoma late last spring. Blooms from the aquatic plant produce a toxin that is deadly to fish. It is not a health threat to humans, other wildlife or livestock.

In cooperation with the Oklahoma Department of Environmental Quality and officials from the Wildlife Department, City of Altus personnel treated the Altus City Lake with ammonium sulfate to hinder the spread of the golden alga. Fisheries biologists spread the chemical at a specific dose in order to kill the alga while minimizing the harm to fish.

“It looks like it has worked. The most recent water tests showed no golden algae in Altus City Lake, and our sampling showed that we saved quite a few fish. Now we just have to hope it doesn’t come back,” Cofer said. “Most importantly we were able to stop or at least slow down the spread of this dangerous alga. This treatment will also help us further our knowledge for possible future treatments in case it turns up in other small lakes.”

Water samples were taken from waters located both above and below the lake, according to Cofer. All tests came back negative except for a sample taken from the western portion of Altus City Lake. Altus City Lake actually has two reservoirs (22 acres and 100 acres) divided by a road.

Cofer along with other aquatic resource biologists from around the state are continuing to monitor the golden alga status in Oklahoma. The Oklahoma Golden Alga Response Team (OGART) was formed to unify these efforts. Made up of a diverse group of state, federal and educational organizations, the
Team is working to devise efficient and effective plans to respond to potential golden alga fish kills. The Team is also looking for proactive solutions to potential future golden alga blooms.

To learn more about golden alga log on to http://www.wildlifedepartment.com/nuisancespecies.htm. The site includes a wide variety of information about harmful golden alga blooms, including scientific research updates, frequently asked questions and up-to-date news.

Anglers who observe fish dying in a particular area of an Oklahoma lake can report their observations to the Oklahoma Department of Wildlife Conservation’s Fisheries Division at (405) 521-3721.