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Florida Blue-green algae update

Weekly Update from the Florida Department of Environmental Protection (DEP)

The U.S. Army Corp of Engineers began discharging large amounts of water from Lake Okeechobee into the Caloosahatchee and St. Lucie estuaries the weekend of Feb. 17-18, 2024, and there are already sitings of algae clusters.

Related stories:

Latest blue-green algae sampling

Feb. 16 – Feb. 22, 2024 – There were eight reported site visits in the past seven days with eight samples collected. Algal bloom conditions were observed by samplers at five of these sites. 

The most recent usable satellite imagery for Lake Okeechobee is from 2/21 and shows low to moderate bloom potential on 15% of the lake, predominantly along the northern, western and southern shorelines of the lake.

Satellite imagery for the Caloosahatchee Estuary from 2/22 shows highly scattered low to moderate bloom potential, predominantly in the upper estuary. 

The most recent usable satellite imagery for the St. Lucie Estuary is from 2/21 and shows scattered low to moderate bloom potential, predominantly in the upper estuary but also at the confluence of the estuary and the Atlantic Ocean. 

Satellite imagery for the St. Johns River from 2/22 is partially obscured by cloud cover, but shows scattered low to moderate bloom potential throughout Lake George and the mainstem of the river down to the city of Jacksonville. 

Please keep in mind that bloom potential is subject to change due to rapidly changing environmental conditions or satellite inconsistencies (i.e., wind, rain, temperature or stage). 

On 2/19, Highlands County staff collected two Harmful Algal Bloom (HAB) response samples. Dominant algal taxa and cyanotoxin results follow each waterbody name. 

Lake Placid – Boat Ramp: Microcystis aeruginosa and Microcystis wesenbergii co-dominant; trace level [0.20 parts per billion (ppb)] microcystins detected.

Lake Glenada – Boat Ramp: Microcystis aeruginosa and Microcystis wesenbergii co-dominant; trace level (0.88 ppb) microcystins detected.

On 2/20 – 2/22, Florida Department of Environmental Protection (DEP) staff collected four HAB response samples. Dominant algal taxa and cyanotoxin results follow each waterbody name. 

Lake Pearl – Park Dock: Microcystis aeruginosa and Pseudanabaena mucicola co-dominant; estimated 1.4 ppb microcystins detected.

Choctawhatchee Bay – Legion Park pipe: No algal taxonomy sample collected; no cyanotoxins detected.

Lake Minnehaha – East Dock: Microcystis aeruginosa; estimated (1.2 ppb) microcystins detected.

Lake Harris – East Central Shore: Results pending.

On 2/21, St. Johns River Water Management District staff collected two routine HAB monitoring samples at two locations. Dominant algal taxa and cyanotoxin results follow each waterbody name. 

Lake Washington – Center: No dominant algal taxon; no cyanotoxins detected.

Lake Jesup – Center: Cylindrospermopsis raciborskii; no cyanotoxins detected.

Last Week

On 2/15, DEP staff collected a HAB response sample from Lake Harris – East Central Shore: Microcystis aeruginosa and Cylindrospermopsis raciborskii co-dominant; no cyanotoxins detected.

Errata from Last Week

There is one date correction for last week’s HAB Summary. South Florida Water Management District’s Lake Okeechobee routine HAB monitoring samples were collected on 2/13 – 2/14 rather than on 2/5.

On 2/13, DEP collected a HAB response sample from Lake Breckenridge – South Lobe. The sample results for Lake Breckenridge – South Lobe were misidentified as results for Chrise Lake. The Lake Breckenridge – South Lobe sample was co-dominated by Woronichinia naegeliana and Dolichospermum sp. and had a trace level (0.30 ppb) microcystins detected.

Results for completed analyses are available at FloridaDEP.gov/AlgalBloom

Caloosahatchee Estuary
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Florida Blue-green algae update 8
Lake Okeechobee & St. Lucie Estuary
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Florida Blue-green algae update 9
St. Johns River
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The blue dots represent positive samples within the past 30 days. The green dots represent tests over the past 90 days. For an interactive version of this map, which allows you to zoom in and read test results for specific test sites for the past 90 days, go to floridadep.gov/AlgalBloom

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Blue-green algae bloom. (Photo courtesy St. Johns River Water Management District.)

Blue-Green Algae statewide dashboard — LIVE map prepared by the Florida Dept of Environmental Protection

More from Florida Rambler: The Florida Red Tide Report


Contributing factors to both red tide and blue-green algae.

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Contributing factors to both red tide and blue-green algae. (Florida Audubon)

Blue-green algae

In water bodies with blue-green algae, if people or animals splash or if boats create wakes, the cyanotoxins in the algae can release into the air. The toxins mix with water droplets and spray—that’s how people and animals can inhale the toxin. These toxins can’t pass through your skin easily so swallowing large amounts of contaminated water is what causes illness. This algae is blue, bright green, brown or red, and can have a strong odor like rotting plants. Pets can become sick from blue-green algae so keep them out of those areas and away from contaminated marine animals and fish.

SYMPTOMS? Stay away from blue-green algae.  For some people, blue-green algae can cause rashes, stomach cramps, nausea, diarrhea and vomiting. People who are very sensitive to smells can have respiratory irritation. Sometimes, high exposures of toxin can affect the liver and nervous system.
If you come into contact with blue-green algae, get out of the area and wash off with soap and water. See your doctor if you think blue-green algae has made you sick.

CONTAMINATED WATER. Water from areas with blue-green algae can make animals and people sick—stay away from these areas.

SWIMMING. Don’t swim in or around blue-green algae.

BLUE-GREEN ALGAE AND FISH.  Fish tested from water with blue-green algae show that cyanotoxins don’t accumulate much in the edible parts — muscle or fillet — of fish, but can in other organs. Rinse fish fillets with tap or bottled water. Throw out guts. Cook fish well.

blue-green algae
Florida Blue-green algae update 10


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