top of page

How do you solve a problem like hydrilla?

Florida Fish and Wildlife Conservation Commission invited constituencies using Lake Apopka to provide feedback on the invasive plant taking over the lake.

"Hydrilla doesn't play well with others," said Dr. Erich Marzolf of St. Johns River Water Management District. The fast-growing plant can grow 300 acres a week. Photo: Center for Aquatic and Invasive Plants, University of Florida, IFAS

Anglers, duck hunters, boaters, wildlife conservationists and advocates for Lake Apopka came from as far as Brooksville and Eustis last week for a meeting hosted by the Florida Fish and Wildlife Conservation Commission (FWC) at Tanner Hall in Winter Garden.

The question on everyone’s minds in the packed hall: What would be done about the hydrilla, a fast-growing invasive plant, currently covering about 10,000 acres of Lake Apopka, or about a third.

Modeling suggests that hydrilla can grow 300 acres a week, according to Erich Marzolf, PhD, director of water and land resources for St. Johns River Water Management District, who gave a presentation about Lake Apopka’s rehabilitation during the meeting. (See VoxPopuli's YouTube for the full presentation.)

Friends of Lake Apopka (FOLA), a nonprofit advocacy group, has joined with the West Orange Chamber of Commerce to petition state legislators “to ensure that FWC has adequate budget to treat 8,000 acres this spring,” Joe Dunn, FOLA past president and board member, said in an email to VoxPopuli. Dunn said FOLA also wants a monitor and control management plan for hydrilla implemented next year.

It wasn’t that long ago that the 30,000-plus-acre lake — the fourth largest in the state — had been so polluted by decades of agricultural run-off from neighboring farms, the fish, birds, even the aquatic plant life had vanished. Marzolf, in his presentation, estimated that decades of drainage from farms added “seven times more phosphorus to the lake than we had historically.”

The St. Johns River Water Management District established a goal to reduce the phosphorus in Lake Apopka to 55 parts per billion, starting in 1996. Last year, the lake’s phosphorus concentration dipped below their target of 55 parts per billion for the first time, said Marzolf.

“That gives plants the opportunity to come back and grow,” he told the crowd. “Plant growth in the lake has exploded.”

That explosion included hydrilla.

Hydrilla is so aggressive, it crowds out native plants. Boaters despise it because hydrilla can get tangled up in their propellers. But perhaps, most compellingly, hydrilla in Lake Apopka is a flood risk. Marzolf explained that because hydrilla, which does not root on the lake bottom, can ball up during storms, it could potentially block the Apopka-Beauclaire Canal, which can lead to flooding.

“That’s our only way to get water out of the lake,” Marzolf said.

Not everyone, however, wants to see the hydrilla reduced or eradicated. Steve Whittun, 40, a duck hunter who came from Brooksville for the meeting, told VoxPopuli that more hydrilla means more ducks. “They’ll land on it. They’ll roost on it, but mostly they use hydrilla as a food source.” Whittun said he’s been duck hunting for three years and noticed a difference last year that he attributes to the FWC’s treatment of the hydrilla. “I feel like it was better two years ago than it was this last season. They treated a good portion of the lake last year.”

Nathalie Visscher, FWC’s invasive plant management biologist, told attendees during her presentation that 6,000 acres of hydrilla were treated with herbicides last spring.

To capture essential feedback like Whittun’s from the various constituencies that use the lake, FWC came up with an effective method to allow everyone to be heard: they placed four identical maps of Lake Apopka in the corners of the room. Stakeholders, who were given comment cards with green and red stickers as they arrived, were invited to place the green stickers on the maps where they wanted hydrilla to remain untouched and red stickers where they wanted the hydrilla eradicated.

Lake Apopka feedback
Four maps, many opinions. Attendees placed stickers where they wanted hydrilla treated with herbicides (red) and where they wanted it left alone (green). Yellow stickers direct FWC staff to feedback on comment cards. Photo: FWC

FOLA’s Dunn thought that worked well with the different groups in the room. “Folks were able to express their opinions without drama,” he said in his email.

Standing among a group of anglers and hunters in front of one such map, Matt Garson, 22, an angler, told VoxPopuli, “I think the fishing’s so good because the hydrilla’s so good.” He came to the meeting in his boat from Magnolia Park. He said his outboard motor gets tangled with hydrilla “every now and then, but if you know what you’re doing, you can get it off.”

Wesley Porak is a Eustis biologist who worked for FWC for 35 years and is now a semi-retired consultant on lake, pond and wetland management. But he’s Team Hydrilla. From a fishing and duck hunting standpoint, he told VoxPopuli, “leave as much hydrilla as you can.”

Let the hydrilla go
Biologist Wesley Porak on leaving hydrilla in Lake Apopka: "I wouldn't say this about any other lake in the state ...It just doesn't have anything going for it... This is the one lake that's the perfect scenario to let the wildlife and the fisheries develop."

“Hydrilla is as good or better habitat than any other plant for bass populations,” Porak said. “The reason that the bass fishing has gotten really, really good is because of the hydrilla.”

He explained that hydrilla provides an area for bass to spawn and gives young bass a place to hide from predators. The plant also attracts the small fish that feed larger bass and other sport fish and invertebrates that cling to the plant and provide food for the very young bass.

“Think about what this could do for the local economy when it’s the biggest mecca for duck hunting in the state and a tremendous area to come bass fish,” Porak said.

FWC recreational use data shows that 77 percent of lake is used for fishing, 18 percent for hunting and 5 percent for boating

“It could provide hundreds of thousands, if not millions, of dollars for the local economy over time if they would let more hydrilla survive in the lake, and it becomes a mecca for the fishermen and the hunters to come,” Porak said.

He said that even within FWC, there’s disagreement about how to handle the hydrilla.

“The fishery scientists, the habitat scientists, and the wildlife scientists and managers told them, do not treat as much hydrilla as you're treating. The invasive plant management section completely ignored them. They didn't take any of their feedback whatsoever. Even though they said it's better for fishing, it's better for hunting, it's better for the habitat management we're doing elsewhere. The invasive plant management people have their own focus. They are very biased that they've gotta get rid of hydrilla.”

FWC spokesperson Carli Segelson emailed this statement Monday to VoxPopuli:

The FWC manages hydrilla on a lake-by-lake basis using a collaborative approach. The FWC makes management decisions after comparing the benefits that low- to -moderate levels of hydrilla can provide for fish and wildlife, and as well as the desires of various stakeholder groups against the impact this invasive plant can have on native plant communities, access and navigation, flood control and management costs.

We have a diverse group of stakeholders with divergent opinions on how much hydrilla they would like on a system based on how they use it. Biologists in our Invasive Plant Management section work diligently to balance these differing opinions. The internal team is made up of scientists from fisheries, waterfowl, restoration, non-game, as well as other subject areas.

Staff are working this week to go over the comments from the meeting as well as those received via email. A plan will be developed and the feedback will be used to inform the plan. The plan must also adhere to the budget, and this will be a large factor in how much hydrilla is able to be targeted as well as how large of an untreated area can be maintained into the future. Overall, we are pleased to be able to present management information to such a large and diverse group and receive direct feedback as to the areas that are important to each individual.

Marzolf acknowledged in a brief interview that hydrilla is beneficial for sport fishing and duck hunting. “Hydrilla provides important habitat,” he said. “It takes up nutrients [from the water] as it grows. The challenge is it doesn't have to grow rooted and so during storms it can get balled up. Hydrilla doesn’t play well with others. Our target of 55 [parts phosphorus per billion] was to get vegetation back in the lake. We just want it to be the native species because it provides the same water quality habitat benefits, but because they’re rooted, they don’t get balled up in storms as easily as hydrilla does.”

Marzolf says that St. John’s water district has earmarked $500,000 in their budget for planting native aquatic plants in lakes.

Across the room where representatives from the town of Oakland, Orange County, FOLA and the Orange Audubon Society are looking at the same maps, the consensus is for eradication.

“The fishermen are the only ones who want [hydrilla] around just for habitat for fish, but the native species [of plants] are better,” Audubon president Deborah Green and a FOLA board member told VoxPopuli. “It’s really the speed of reproduction. We’ve got to keep at it aggressively.”

Deborah Green Orange Audubon
Deborah Green, president of Orange Audubon Society, advocates for "aggressive" treatment of hydrilla. Photo: Norine Dworkin/VoxPopuli

Austin Arthur, 37, of Winter Garden, who’s running for Orange County commissioner in District 1, described hydrilla in a text message to VoxPopuli as “the biggest problem the lake has right now.” An active FOLA member, Austin wrote that he supports FOLA’s push for eliminating 8,000 acres of hydrilla, but added that he could “see a path where we can work together to settle on a plan that removes the great threats of hydrilla without fully removing the asset it is for some of the stakeholders in this conversation."

District 1 Orange County Commissioner, Nicole Wilson, a regular champion of environmental causes, said she was taking her lead from FWC and the St. John’s water district. “I said, What is your take on this? And they said, We support the ecosystem. What that tells me is that research will show where they need to address some of the things that are more pressing, and they have to follow the science.

“As long as the residents are being heard and the different groups that are nervous about their particular interests are being heard, hopefully they can strike a balance.”


bottom of page