Lake Austin -- Early Thursday morning, the City of Austin will dump another 9,000 carp into Lake Austin. That's on top of tens of thousands already added to try to control a growing problem with Hydrilla.

The invasive weed can choke out native plants, trap swimmers and has already caused half a million dollars worth of damage to Tom Miller Dam, but some say the city's solution is really just another problem.

“What it's going to do, no one knows, and that's part of the issue,” said local bass fishing guide Robert Brown.

Brown, like many people, has a lot of questions about the growing number of Asian Grass Carp dumped into Lake Austin.

“You're changing an ecosystem, and I don't like that you're invading the ecosystem,” he said.

Mary Gilroy with Austin's Watershed Protection Department tells KVUE they also worry about the ecosystem.

“There are some concerns when you stock grass carp in the lake as to how they will impact the fish that are already there," Gilroy said.

However, Texas Parks and Wildlife has studied the lake since they introduced grass carp, and Gilroy says "we wouldn't be doing this if they weren't on board, because they're the ones that permit those fish for us."

Some fishermen say they don’t want Hydrilla wiped out from the lake, because it actually helps the bass.

“All the bass fisherman, we love the Hydrilla. It produces oxygen in the water and provides a habitat for the bait fish to grow and thrive," a fisherman said.

“For us, it's like a fish hotel, and the fish just go in and out of it,” said Lake Austin fisherman Loy White.

The City of Austin says the carp are the most effective way to cut down on the growing Hydrilla problem.

Thursday’s delivery will make for a total of approximately 33,000 grass carp in Lake Austin, for an estimated 55 carp per acre of Hydrilla.