They arrived drugged, ready to eat weeds

By Mike Anderson

At 8 a.m. June 8, a truck arrived at Duke Energy’s Riverbend Steam Station, parked about 25 yards from the shores of Mountain Island Lake and pumped 500 fish through a long, white tarp tunnel into the water.

The carp, which the crew drove from Arkansas, were mildly drugged for the ride around North Carolina. Upon entering the water, a couple stragglers remained close to the tarp and swimming in circles for a while before they eventually found their way to begin doing work on the lake.  

This stop at Riverbend Steam Station was the truck’s second of the day. The truck’s crew also released 500 carp into Lake Wiley and 1,200 into Lake Norman that day, Duke Energy representative Erin Culbert said.   

The job of the fish: Eat. They’re supposed to digest noxious weeds, or any plant that the N.C. Aquatic Weed Council designates as harmful to the environment. All the plants come from other parts of the world, and American ecosystems like Charlotte’s are not prepared to accommodate them. These weeds disrupt water routes, cause erosion and flooding, foster growth of mosquitoes and other pests, crowd out recreation space and compete with other, more beneficial vegetation.

Most importantly, the carp protect the quality of the Charlotte region’s drinking water, according to Karen Whichard, a spokeswoman for Charlotte-Mecklenburg Utilities. 

The fish have met expectations, too, as the weeds have remained under control in all three lakes.

The state, Charlotte-Mecklenburg Utilities, the City of Gastonia and Duke Energy collaborate on the carp project. Mountain Island Lake began to have a problem in 2000, but in the decade since then, the carp have proved a wise government-business investment. The four groups pay to restock Mountain Island Lake annually, and the N.C. Aquatic Weed Control Council keeps an eye out for any further growth and sometimes calls for supplemental carp re-stockings, including the June 8 delivery.

Thanks to the weed eaters, the shores of Mountain Island Lake are relatively clean, whereas they used to be covered in a weed called hydrilla, according to Whichard. 

Although herbicides and mechanical equipment do the trick, too, the fish are ideal eradicators, Whichard said. “It allows us to treat the weed infestation without using chemicals” that might reduce the quality of drinking water.  

While carp have become infamous in Lake Michigan because they are multiplying and crowding out native species, the fish delivered to Charlotte-area lakes do not pose the same threat. The carp were sterilized before they entered the lakes.

The fish survive about eight to 10 years, according to Bobby Bowen, one of the Duke Energy crew at Mountain Island Lake on June 8.

This method is relatively cheap, too. The 500 new fish in Mountain Island Lake cost about $2,500, Whichard estimated.  The state foots 50 percent of the bill while the other three groups split the rest.

Although originally foreign, these weeds have found a home in local aquarium shops and other venues. In tropical fish tanks, the plants are decorative and seemingly harmless.  They become a problem, though, when people dump their fish tank’s contents off their boats and into the lakes. Indeed, the weeds’ spread is mostly accidental. Trailers also pull up the plants and unknowingly deposit them in other lakes.  

A 1996 report by the N.C. Department of Environment and Natural Resources names another, decidedly more reckless and insidious way through which people introduce the weeds into state lakes. Some fishermen purposefully introduce the weeds to make fishing easier: If uninhibited, the plants grow rapidly and restrict fish’s movement, therefore leaving them more vulnerable to fishermen.

Whichard said she does not know how prevalent the activity is in local lakes.

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