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The decision to stock sterile grass carp was made just a few years after the invasive aquatic vegetation hydrilla was discovered in the lake in 2007. At the time, there was concern the fast-growing aquatic weed would clog coves and make boating and other recreation difficult where it was thickest.

Hydrilla has spread to bodies of water throughout the United States since the 1950s when it is thought to have been dumped from an aquarium into waterways in Florida. The plant is believed to have originated in Asia.

According to records provided by the Tri-County Lakes Administrative Commission, hydrilla was found in 10 locations between channel markers B10 and B12 on the Blackwater River section of the lake. By 2012, hydrilla had spread to dozens of patches around the lake.

When it was first discovered, TLAC used a herbicide to kill the hydrilla where it was growing which proved to be expensive. In 2012, TLAC spent $150,000 to treat 189 acres of hydrilla with herbicide.

TLAC Executive Director Kristina Sage, who served as a board member during that time, said there were concerns that the cost to treat the hydrilla with herbicide was growing too large for the organization’s budget. TLAC is provided with funding from each of the counties that surround Smith Mountain Lake which includes Bedford, Franklin and Pittsylvania counties.

The other concern with hydrilla is that it currently seems to be impossible to completely kill. Herbicides would kill the plants for a time, but they would reappear the next year. Removing the plant has also been found to be unsuccessful since it can regrow from fragments, roots or even tubers that grow from the ends of underground stems.

With the growing cost to treat and the difficulty to eradicate, TLAC was given permission by Appalachian Power Co., which administers the lake, and the Virginia Department of Wildlife Resources to stock 6,000 sterile grass carp in Smith Mountain Lake in 2013. The cost for the stocking was $30,000.

The carp were introduced into Smith Mountain Lake in March 2013. According to reports at the time, surveys of the lake floor the following September saw “barely any stubbles of hydrilla” in any of the areas that had once been inundated with the plant.

There were some unintended consequences of the carp. TLAC board members were hopeful the carp would stick to feasting on hydrilla and leave other native vegetation alone, which was not found to be the case.

Dan Wilson, a fisheries biologist with the Virginia Department of Wildlife Resources, said that hydrilla is a preferred meal for the sterile grass carp. The fish will gladly look to other vegetation once the hydrilla is no longer available.

In the years after the grass carp was introduced, they removed all signs of hydrilla as well as nearly all other aquatic vegetation in the lake. That angered many fishing enthusiasts who live at and visit Smith Mountain Lake. Aquatic vegetation is a common hiding place for fish and is seen as a good place to cast a line.

“We had grass we could go to where we could catch fish, now it is all gone,” said Dewayne Lamb, avid fisherman and owner of Indian Point Marina.

Now 12 years later, those sterile grass carp are reaching the end of their lifespan and vegetation is slowly returning to Smith Mountain Lake. With that, hydrilla is also making a comeback.

Sage said some hydrilla has once again been found in certain areas of the lake. The amounts were not large enough for any remediation efforts this year, she added.

If the spread continues at a rate like it did in the years after it was first discovered in 2007, steps will likely have to be taken in the coming years to combat the hydrilla. Sage said additional grass carp is likely the best, and most cost-effective option, but a step they will wait to take.

Sage estimates it could be as many as three to five years before any additional sterile grass carp are needed.

“We don’t want to put any additional grass carp in until we need to,” Sage said.

There is also some consideration on how many sterile grass carp should be introduced. Sage said the 6,000 carp were seen as a low estimate at the time with discussions to possibly stock more, but they proved to remove the hydrilla as well as all other aquatic vegetation.

According to Sage, if sterile grass carp are once again introduced, they will be released in much smaller numbers. Plans are to also release the carp over time in stages to see how well they are working.

Wilson said finding the right balance of carp to combat invasive vegetation while keeping native vegetation has proven difficult. Other lakes that have introduced sterile grass carp so far end up stocking too many and having them eat all aquatic vegetation or too few where they are unable to remove the invasive vegetation.

“Nobody has been able to pin down an exact formula,” Wilson said of previous efforts to calculate the number of carp needed.

Wilson also admits that hydrilla has not been found to be harmful to Smith Mountain Lake. It is seen as a detriment to recreation when it grows to large, thick patches that choke off coves, but a valuable fishing location for anglers.

“Biologically, having hydrilla or some of the other plants coming back isn’t necessarily a bad thing,” Wilson said.

He sees the issue of hydrilla as a divide between those that use the lake for recreation and those that use it for fishing. The two sides have a very different opinion on whether the sterile grass carp should be restocked.

“From the angler standpoint, no,” Wilson said. “From other dock owners and other recreationalist who use the lake, the answer would probably be yes.”

Wilson said Smith Mountain Lake is different from other lakes in that it is much deeper. Hydrilla usually doesn’t grow much beyond 20 feet deep due to the lack of sunlight. Because of that, it is unlikely for hydrilla to grow in much of the main channel and deeper areas of the lake.

Lamb said he and other fishing enthusiast at the lake are adamantly opposed to any additional carp being introduced into the lake. He said TLAC failed to take fisherman into account when they decided to stock the carp in 2013.

“I’m not for it,” Lamb said of possibly restocking the lake with the carp. “I will fight it tooth and nail.”

Lamb said there are areas of the lake where there is no development where hydrilla growth would not be a problem and could be beneficial for fishing. The solution should not be removing all vegetation like what was done in 2013.

“It’s our lake, too” Lamb said. “It is not just their lake.”

Lamb said TLAC should go back to using herbicide in some areas of the lake to kill the hydrilla. If cost was a concern, he said developments or communities could apply to use the herbicide similar to how some developments apply for permits to dredge from the bottom of the lake to increase water depths.

Lamb was part of a program that stocked F1 tiger bass into the lake starting in 2015. The goal of the program was to grow the bass, a genetic mix of northern bass that grows faster and a Florida bass that grows larger, that would improve fishing at the lake. He said the lack of vegetation has probably had a negative impact on the bass since the bass had no place to hide from predators when they were first stocked as fingerlings.

While young fish do use vegetation as a hiding place from predators, Wilson said the loss of aquatic vegetation does not seem to have had a negative impact on the number of fish in the lake.

Even if the impact on fish is questionable, Lamb said there can be an impact on revenue for the three counties surrounding the lake. Fishing enthusiast spend money at Smith Mountain Lake just like other vacationers on meals, gas and other services. He said the only difference is that fisherman frequent the lake year round instead of just the summer season.

Fishing could improve with the addition of more vegetation in the lake, according to Lamb. Any additional grass carp would likely remove all of that once again.

“Grass carp is not the answer,” Lamb said.