A state fisheries biologist says Wednesday and Thursday's major fish kill at Silver Lake was a natural occurrence due to oxygen depletion and not from a recent herbicide spraying.

Kerry Prather, district fisheries biologist for the Kentucky Department for Fish and Wildlife Resources, says he's also received calls of fish kills in Bullitt, Oldham and Boone counties. And he expects more calls in the next few days.

"These things are so common we do not investigate them," Prather said Thursday afternoon. "Fish and Wildlife does not investigate private pond and lake fish kills because there are so many of them. It's a natural phenomenon, summer through fall."

Prather, who has a "fledgling business" not associated with his state government job, was hired by the Silver Lake Homeowners Association to spray a herbicide on vegetation around the lake. The spraying occurred on Saturday.

"I treated creeping water primrose, which was on dry land," Prather said. "Nothing was sprayed in the water. It was a product called Reward. The active ingredient is Diquat, an approved aquatic herbicide.
"This is a terrible concidence and I can see where people would think (the spraying and the fish kill are related)." But they're not related, he said. "I've tried to calm everybody's fears."

Thursday morning, residents of Silver Lake Farm subdivision " across U.S. 460 from Lakeview Park " said more than 200 fish had died including several large fish.

Howard Dawson, Phillip Ellis and Wallace Boggess " neighbors on Silverlake Boulevard for the past 12 years " said the lake level is at an all-time low, and this is the first major fish kill in the four-acre lake.
Boggess, a board member of the Silver Lake Homeowners Association, said the lake is probably no more than three feet deep.

Prather said in the summer months, "in warm water, there is a lower oxygen level anyway." Also, there is a leak in Silver Lake, several feet down, he said. So the fish population is compressed into a much smaller area, and "their waste products tax the oxygen levels," he said.

"The microscopic plants in ponds and lakes are the main producers of oxygen for fish," Prather said. "On cloudy days, with less sunlight, you have less photosynthesis, which produces the oxygen. More oxygen is used up than is produced."

He said fish kills usually occur right before dawn, "and these kills seldom kill everything. I think residents will be surprised at the fish that are still present in the lake."

"You also have to look at what is going on in the watershed," Prather said. "A lot of people in Silver Lake (subdivision) fertilize their lawns, maybe two or three times a year. A lot of that washes into the lake with rainfall from year to year."