Aquatic spraying programs explained in detail

Posted 3/13/19

MOORE HAVEN — Glades County Board members had plenty of questions for them during and after game commission officials’ presentation about state programs for controlling exotic and invasive …

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Aquatic spraying programs explained in detail

MOORE HAVEN — Glades County Board members had plenty of questions for them during and after game commission officials’ presentation about state programs for controlling exotic and invasive aquatic plants in Lake Okeechobee and other Florida waterbodies.

Matt Phillips, a biologist in the Florida Fish and Wildlife Conservation Commission’s invasive plant management section, spoke for around an hour during the commissioners’ morning meeting Feb. 12, giving them an overview of how FWC uses the tools at its own disposal and many hired contractors to manage the pesky vegetation. He brought with him an entourage of some of the experts and scientists involved in the efforts that the FWC recently suspended for a few weeks but announced Feb. 21 would resume soon.

Mr. Phillips introduced some of the commission’s “valuable partners” in the never-ending struggle to contain invasives: Jon Lane of the U.S. Army Corps of Engineers; Danielle Kirkland, head of field operations for FWC; Francois Laroche of the South Florida Water Management District; Jessica “Skippy” Fair of USACE; Tyler Green, a biologist with the USACE based in Okeechobee; Andrea Dominguez, fishery biologist for Lake Okeechobee; and Stacy Wilson, deputy director of the Division of Florida Fisheries Management. The USACE in concert with the FWC and its partners actually run twin programs — terrestrial, or “upland,” and aquatic. In the land category, work is done on about 11 million acres statewide, with 160 projects financed each year, including removal of, for example, the Burmese pythons that have been spreading in the Everglades. The aquatic program is far more extensive, with 350 active management programs on 463 Florida lakes and rivers, covering 1.26 million acres of water. They include private property, public boat ramps and fish/wildlife management areas.

Science behind spraying
Mr. Phillips stated that an appreciable amount of scientific work goes into planning of aquatic plant control decisions. He said more than 270 projects have been financed since 1971 with institutional partners from around the Southeast, including the University of Florida, Louisiana State University and North Carolina State.

County Board Chairman Tim Stanley said many people had been asking the commissioners to join petitions for stopping spraying on Lake O. “I think that we need to be informed on what’s really happening and what the goal is here,” he said, adding that if spraying were ceased, then the public outcry would be not from coastal environmentalists so much as people who use local waters, such as boaters, commercial and sportfishing interests.

Mr. Stanley noted that anglers have complained the fishing hasn’t been very good this year, and that hydrilla seems to have disappeared, but said he knew that without management the waterways could return to being choked with vegetation like they were in the 1800s. He asked Mr. Phillips to explain what they are targeting.

Mr. Phillips said water hyacinths and water lettuce were the two main floating plants needing to be controlled on Lake O, and that if they were left to grow without interference, they would put quadruple the muck material at the lake bottom than if they’re eliminated before the growing season.

Vice Chairman Weston Pryor asked Mr. Phillips whether hydrilla was being sprayed. He answered that it hasn’t been on a large scale since the early 1990s, with only spot treatments done recently at access points. Mr. Pryor said the water in Lake Okeechobee was “crystal clear” when there was hydrilla.

Submerged plants as filters
Mr. Phillips explained Lake O has a lot of submerged vegetation, including also eelgrass, pondweed and coontail — natural filtration systems, all — but that they come and go in different weather conditions. Storms such as Hurricane Irma cause turbidity that reduces sunlight to the plants, and they die. He agreed that the lake needs more submerged plant life and said the FWC favors lake levels to be maintained at between 12 and 15.5 feet because higher lake levels kill marsh vegetation, and occasional lower lake levels let more light reach the bottom and encourage natural plant growth. He also supports clearing of dead matter through fire.

Commissioner Donna Storter Long questioned how controlled the spraying was, and the toxicity of herbicides that are used. Mr. Phillips said the federal Environmental Protection Agency and Florida’s Department of Agriculture and Consumer Services are the regulatory authorities and that there have been complaints about spraying in the past, which EPA or the DACS will investigate. Private contractors hired by the FWC also are subject to EPA and DACS regulation, inspection and investigation. He also said all products used in the water would break down eventually.

Mr. Stanley asked whether there were any plans to plant submerged vegetation on the lake while water levels are lower, and he replied that although it had been done in the past, some questioned how much effect that could have on an ecosystem as large as Lake Okeechobee.

Burning effective but tough
Mr. Pryor wanted to know why more burning wasn’t done of dead vegetation on the lake and its banks when the water is lower. Mr. Phillips explained that it’s hard to get burn authorizations from the Florida Forest Service for large-acreage areas because while it’s a great tool, all the conditions must be right.

Commissioner Donald Strenth asked about videos he’d seen from local fishermen of apparently indiscriminate spraying by Applied Aquatics workers in open waters on Lake O. Mr. Phillips said he’d love to see those and that if anyone had any issues, they should take any evidence, like photos or videos, to the FWC for investigation. Mr. Strenth replied that he’d send him one.

In reply to a query from Mr. Stanley, he also said there is a real-time schedule online at for spraying programs in progress or scheduled, but that sometimes more than one agency is conducting operations on Lake Okeechobee at the same time. He added that the University of Florida’s Institute of Food and Agricultural Sciences has a web page with voluminous information about invasive and exotic plant management at

Mr. Phillips reminded everyone that public comments still could be made to the email

Chris Felker can be reached at