'Killer algae' spotted in Punta Rassa, threatening marine life and ecosystem

LEE COUNTY, Fla. —

In Punta Rassa, a thick algae known as Caulerpa, or "killer algae," is spreading along the shore, posing a threat to marine life and the local ecosystem.

"It's blooming. It's getting fast. It's taking over everything," said Brandon Brown, a dock builder who has witnessed general algae in the water. Brown noted that while deep-sea fishing, he has caught fish with algae growing on them, something he had never seen before.

The macroalgae, first observed by Sanibel-Captiva Conservation Foundation research scientist Richard Bartleson in 2006, began to thrive in 2018. It now covers the seafloor around Punta Rassa and Matlacha.

"It's getting the perfect conditions to grow here," Bartleson said. The algae thrives on nutrients from septic systems and fertilizers entering the Caloosahatchee River from Lake Okeechobee.

The algae is called "killer algae" because it smothers native plants like seagrass and can irritate human lungs. However, its main impact is on marine life.

"So the other effects people will see is lack of fish, they go out fishing, there's no fish. That's because this killed all the fish food, all the things the fish ate. It takes all the oxygen out of the water, kills all the clams, oysters, worms, shrimp, kills everything," Bartleson said.

The Caulerpa algae will eventually die off in the summertime due to higher water temperatures.

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