Town Considers Algae-Eating Fish


A scaly creature that can eat four times its body weight in green slime every day sounds like the subject of a bad horror film. But for town employees responsible for keeping the Green Valley lakes healthy, it would be a welcome guest.

Every summer, a large ring of algae and lake weed begins to form around the popular park lakes.

"It's just the annual nightmare that comes with lake management," said Bill Schwind, Payson Parks and Recreation director. "When you have a lot of sunlight, warm weather, shallow water and fertilizer, you're going to grow plant life."

Some algae growth is just fine, according to Karen Probert, town water quality specialist.

"Algae is not really a problem unless it's excessive," Probert said. "If it gets excessive, algal bloom can use so much oxygen, it takes away from everything that lives in the lakes. When that happens fish and other organisms can die."

Probert said that less algae also makes a better looking lake.

"Sometimes people drive by here and think, ‘Oh, something is wrong with the lakes,' when actually this is high-quality recharge water," Probert said.

The recharge water from the three Green Valley lakes filters through the bottom of the lakes and into the drinking water aquifer. The water is cleaned naturally as it seeps down through many layers of soil and decomposed granite.

"We do extensive testing on all of our drinking water wells and we meet or exceed all drinking water standards," Probert said.

So using chemicals to fight the algae menace is not an option.

"I could have this water looking as clean as the water at Taylor Pool if I wanted to use chemicals," Schwind said.

"We're using biological treatment because we don't want to take a chance that any chemicals could possibly end up in our drinking water," Probert said. "Our primary objective is to protect public health."

That's why the town is seeking a permit to introduce a new biologically safe weapon with fins.

"We're working with Game and Fish to get permission to use an algae-eating carp," Schwind said. "Game and Fish has to approve us because these are artificial lakes.

The reason Game and Fish officials are concerned about stocking the grass carp, or White Amur, is the possibility that the fish could escape the man-made lakes into a natural environment where they would then compete against native fish for food. The White Amur can eat up to four times its body weight every day in weeds and algae.

"The Amur that are introduced into artificial lakes are sterile and can't reproduce, but they may still be a threat because if there was a major storm event and water from the lakes overflow, then the fish could be transported into the natural environment like the East Verde River," Probert said.

The construction of a fish fence might be the deciding factor.

"We've talked to the Game and Fish Department. We need to construct fish barriers along the west end of the largest lake to be able to obtain the permit to stock the Amur in the lake," Probert said. "Those barriers may be constructed by the end of the year."

Probert also answered the big question on every fisherman's mind:

"Yes, they are very good to eat, but if people eat too many of them they won't be able to do their job."

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