Oxygen-depleted water along the Betty’s Branch tributary of the Savannah River was the likely cause of death for as many as 5,000 fish, officials said.
Dead fish of varied sizes and species were seen over the weekend both upstream and downstream of the boat launch area at Columbia County’s Riverview Park.
Georgia Department of Natural Resources officials found extremely low levels of oxygen in Betty’s Branch.
“They were seeing dissolved oxygen levels below 1 milliogram per liter,” regional fisheries supervisor Steve Schleiger said.
Although no specific cause of the low oxygen was identified, a possible cause could be decaying organic matter flushed into the stream during recent heavy rains.
Authorities estimated that 5,000 fish were killed, Schleiger said.
By Monday afternoon, oxygen levels were recovering and had risen to 3 milligrams per liter in Betty’s Branch, while water quality in the main river channel remained normal, with oxygen levels of 5 to 6 milligrams per liter.
“We believe the actual fish kill is over and that all the fish that are going to die appear to have died,” Schleiger said, adding that live fish caught in the area are safe to eat.