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DNR: PTC fish kill germ no threat to humans

By JOHN MUNFORD
jmunford@TheCitizenNews.com

Two naturally-occurring parasites killed the thousands of dead fish that washed ashore on Lake Peachtree in early December, an effect that later extended to adjacent Lake Kedron, state officials said.

The parasites are common to freshwater systems and not known to pose a human health risk, said Wildlife Resources Division Biologist Brent Hess.

Local residents were initially concerned because both lakes serve as reservoirs for the Fayette County Water System, but the fish weren’t killed by any toxic chemicals, said Water System Director Tony Parrott.

What made the Dec. 6 incident unique was that the dead fish were all gizzard shad, and the other bass and bream fish in the lake were not affected, Hess said. And there were a lot of them, Hess noted.

The shads’ immune system may have been compromised by a severe fluctuation in water temperature, or it could have been a case of overpopulation, Hess said. In the latter instance, the fish don’t have predators keeping the population at a reasonable level and they can grow so large in size and number that “there’s nothing to prey on them,” Hess said.

“We believe something happened to stress them ... allowing the parasites to take hold,” Hess said.

The state Environmental Protection Division, which regulates drinking water standards, is not worried about the incident being due to poor water quality, Hess said.

“We feel like there are no long-term effects,” Hess said, adding that biologists were going to take a few sample fish from the lake yesterday for further testing.

Some shad may have survived and the population could build up in the lakes over the next few years, Hess added.

Lake Peachtree is unique because the bass and bream hang out on the edges of the lake and the shad tended to congregate in the middle of the lake where the water is a little deeper, Hess noted.

“They don’t go to the same buffet,” Hess said.

The Costia and Trichodiniasis parasites were identified after some of the dead fish were studied at the Auburn University Fish Disease Laboratory, officials said.

“They found an unnaturally high number of those parasites,” Hess said, noting that while fish kills occur naturally, it was uncommon to see it affect one particular species and in this quantity.

The local situation is also unique because access to the lake through Peachtree City’s cart path system allows observers to keep a keen eye on the lake’s health, Hess said, noting that many residents called to report the dead shad.

“We’re still looking at it, and if anything new comes up we’ll put it out because the public has been so interested,” Hess said.

Since the Dec. 6 incident, the water system hasn’t been pumping water from Lake Peachtree, which is fed by Lake Kedron, Parrott said. The reason is strictly cosmetic: Officials want to get the dead shad, which are still cropping up, as recently as Saturday, Parrott noted.

That wouldn’t be possible in the summer months, when demand for water runs high, but December and January are the two months of the year when demand is at its lowest, Parrott said.