June 8, 2014

More weed-eating carp added to Lake Murray

More weed-eating carp added to Lake Murray to keep hydrilla and other underwater weeds in check.

More carp are at work in Lake Murray, keeping hydrilla and other underwater weeds in check.

State natural resources officials put in 1,100 of the finned weed-eaters in mid-May — half on the north shore and half on the south waterfront — after officials saw unwanted greenery begin to proliferate.

It’s the start of what is likely to be an annual addition of fish that are the main strategy for weed control in the 47,500-acre lake.

The addition is the first since state officials put in 64,500 carp in 2003 to stop the spread of hydrilla, a weed that turned some areas into underwater jungles.

Slightly less than 4,000 of the original carp remain, officials estimate. The fish are sterile, so they don’t reproduce.

But their impact has been considerable.

Today, no more than 50 acres are troubled by weeds of any kind, according to a recent inspection.

Primrose has replaced hydrilla as the biggest nuisance and only in minor amounts, said Chris Page, who oversees state aquatic weed control.

Hydrilla, a non-native weed, was discovered in the lake in 1993. Anglers apparently brought it in as fish food without recognizing the problems it would cause, a study of the weed found.

Initial use of herbicide and drawdowns for hydrilla control ended amid concern about spraying chemicals in a lake that supplies drinking water. Also, boaters were unhappy about the frequent transformation of shallow coves into mud.

Carp keep the lake in good shape for recreation, according to leaders of the Lake Murray Association – despite complaints from some anglers that their sport suffers because the fish consume too much greenery that also feeds game fish

Preventing a revival of hydrilla is vital, association president Andy Hyman of Chapin said.

The amount of carp being put in will keep weeds at bay without affecting game fishing much, if at all, state officials say.

“That’s the key, keeping it all in balance,” Page said.

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