Use of carp to control Thurmond Lake hydrilla to be debated

Biologist Ken Boyd holds a sample of hydrilla plants from Lake Thurmond.

Surveys about using sterile grass carp to control hydrilla at Thurmond Lake will be shared with state wildlife agencies this fall, but tight federal budgets may have no room for new programs next year.


The survey, launched in February by the University of Georgia, was designed to poll about 8,000 stakeholders about hydrilla, which was first discovered in the reservoir in 1995.

Despite periodic herbicide treatments, it has since expanded to almost 5,000 acres, including about 640 miles of shoreline.

Although the invasive weed provides cover for fish, it also harbors a microscopic algae bloom that forms a neurotoxin that has killed at least 60 bald eagles along the lake.

The main solution under study involves introducing sterile grass carp into the lake, in hopes that the fish will eat enough hydrilla to stop its spread and prevent or reduce the eagle-killing condition, known as avian vacuolar myelinopathy, or AVM.

Scott Hyatt, the Army Corps of Engineers operations project manager at the lake, said UGA is still working on the final analysis of the survey.

“We actually got the latest draft results Monday,” he said. “We may ask some additional questions of UGA, and then the results will be distributed to the states for comments and questions.”

Officials in South Carolina seem to favor the idea, while Georgia authorities have voiced concerns that the carp would also consume native vegetation in the lake, further altering its environment.

The Army Corps of Engineers, meanwhile, wants to get as much data as possible before deciding on how to proceed.

“The next step will be to formally propose actions we can take, probably through an Environmental Assessment or an Environmental Impact Study,” Hyatt said, noting also that such steps would include the public – most likely in the form of stakeholder meetings.

The grass carp, which are sterile and cannot reproduce, have been used successfully in other areas for weed control, but stocking the 70,000 acre lake with enough of the fish to control hydrilla would be costly.

Even if the neighboring states signed off on a carp program, it may not be financially feasible next year.

“Given the funding projections we’re seeing for the Thurmond project’s 2014 fiscal year, I doubt we’ll be able to move ahead with any hydrilla treatment plans,” Hyatt said.

Weed control plan studied to reduce eagle mortality at lake
Hydrilla's future being debated at Thurmond Lake
Survey to explore grass carp option for Thurmond hydrilla
Thurmond Lake hydrilla infestation expanding
Herbicide plan will target river weeds


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