The first attempt to wipe out hydrilla on Lake Wylie isn't working. The invasive plant is spreading and can now be found on four sites along the northern tip of Lake Wylie.
Dale's Landing in Mecklenburg County is now almost filled in with the weed, said Charles “Bo” Ibach, chairman of the Lake Wylie Marine Commission.
Other infestation sites are at South Point Access, the Belmont water intake and just above the Interstate 85 bridge, all on the North Carolina side of Lake Wylie.
“It's there and growing,” Ibach said.
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In May, 500 sterile Asian grass carp were introduced near the initial site in hopes that the fish would eat away at the plant, which grows up to a foot each day. Ibach wanted 1,600 fish, but the S.C. Department of Natural Resources asked for only 500 to be used.
“We've pretty much come to the conclusion that next spring, we're going to try and put in at least 2,000 carp and maybe even more than that,” Ibach said. “That little 500 carp we put in, they haven't got a prayer.”
Chris Page, program coordinator with the DNR's Aquatic Nuisance Species Program, said before the May stocking that 500 fish likely would be enough to control the hydrilla and that adding too many fish could endanger natural plant growth in the lake.
Given the additional growth, Page said he still doesn't believe the number of fish stocked was too low.
“Carp don't normally work immediately, and it may take two to three years to show good results for control of hydrilla. In the meantime, herbicide control methods should be utilized,” he said. “I think that the best thing to do is to wait until Duke Energy crews have done a thorough survey of the lake and we really know the extent of the hydrilla infestation.”
Late last month, Duke crews sprayed the aquatic herbicide Komeen on the known beds of hydrilla on Lake Wylie.
The environmentally friendly herbicide is copper based and is used in water treatment plants to kill algae, Ibach said.
Duke will return in about six weeks to spray, said Duke Energy spokesman Rick Rhodes, who confirmed that his crews are seeing more of the weed, presumably from boat propellers or other factors breaking the plant up.
Ibach hopes the spraying will stabilize hydrilla beds until more fish can be stocked next spring.
Still, Duke is not committing to adding 2,000 fish next spring, Rhodes said.