LAKE WYLIE -- Early next month, 500 sterile Asian grass carp will be dumped into Lake Wylie.

Why? Because, for more than a year, Lake Wylie officials have been working to identify and eliminate hydrilla, an invasive plant species spreading through the lake. The best way to do it, they say, is to stock the lake with sterile carp that feed on the predominately water-based weed. The original plan, which called for 1,600 fish, was recently reduced to 500.

"It's not enough," said Charles "Bo" Ibach, vice chairman of the Lake Wylie Marine Commission. "I really think we needed more. I wanted to be more proactive."

But Ken Manuel, head of the Duke Energy Aquatic Weed Program, called the amount "adequate" and said more could be added if needed.

Hydrilla is a non-native plant species that originated in tropical climates. It attaches to the bottoms of waterways and can grow up to a foot each day. Experts agree the plant was likely introduced to Lake Wylie from some sort of aquarium. If left to grow undeterred, Hydrilla can make water bodies unusable for swimming, boating or even drinking water.

So far, hydrilla has been spotted only on the North Carolina side of Lake Wylie, near the Interstate 85 bridge. Experts estimate about 20 acres are affected by the plant.

The grass carp will be released just south of the N.C. 74 bridge. At $6 per fish, the stocking will cost $3,000, to be divided by North Carolina ($1,500), the marine commission ($750) and Duke Energy ($750).

The plan to reduce the number of stocked carp from 1,600 to 500 was made when the S.C. Department of Natural Resources began negotiations with the marine commission, Duke and the N.C. Department of Environment and Natural Resources. The latter three favored the higher number, but South Carolina experts offered a different opinion.

Chris Page, program coordinator with the S.C. DNR Aquatic Nuisance Species Program, said some anglers like the idea of hydrilla because it provides fish cover and reduces the amount of water fish have to swim.

Page said 500 fish will be enough and wants to balance the needs of ridding the lake of hydrilla with native plants that could be eliminated by too many fish.

"We believe that, being a border lake, (South Carolina) should have some say in it," he said.

Though disappointed with the lower number of fish, Ibach said he understands Lake Wylie's position on two states creates issues of compromise.

Efforts now shift to making anglers aware of the carp before they're introduced to Lake Wylie.

"They need to know it's illegal to have one of these fish," Ibach said. "It's technically illegal to catch one, but definitely if you catch one, you've got to catch it and release it."

According to U.S. Fish and Wildlife Services, grass carp have an oblong body and broad head, and they're usually dark gray, although the sides are lighter with a gold sheen. Grass carp can grow to be about 4 feet long and weigh up to 50 pounds.