Weekly Update from the Florida Department of Environmental Protection (DEP)
May 19 – May 25, 2023 – There were 32 reported site visits in the past seven days with 32 samples collected. Algal bloom conditions were observed by samplers at 17 of the sites.
Satellite imagery from 5/25 for Lake Okeechobee shows moderate to high bloom potential on approximately 60% of the lake with the most intense bloom potential on the southern half. Satellite imagery from 5/25 for the Caloosahatchee and St. Lucie estuaries shows no bloom potential on visible portions of either estuary.
The most recent usable satellite imagery from 5/21 for the St. Johns River shows moderate bloom potential on Lake George extending down the mainstem of the river to Green Cove Spring, and no bloom potential from Green Cove Spring to downtown 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.)
Recent blue-green algae headlines
- Is the Caloosahatchee heading for an algae bloom? Fort Myers News-Press, May 26, 2023
- Understanding blue-green algae, Stuart Magazine, May 26, 2023
- Large algae bloom spotted on Florida’s Lake Okeechobee, Fox Weather, May 24, 2023
- Health advisory issued on blue-green algae in Lake Okeechobee, WGCU Public Radio, May 23, 2023
On 5/22-5/25, Florida Department of Environmental Protection (DEP) staff collected harmful algal bloom (HAB) response samples from 14 sites. Dominant algal taxa and cyanotoxin results follow each waterbody name.
• Lake Lotela – Boat Ramp: Microcystis aeruginosa and Botryococcus braunii co-dominant; no cyanotoxins detected.
• Lake Okeechobee – S308C (lakeside): Microcystis aeruginosa; no cyanotoxins detected.
• C44 canal – S308C (canal side): Microcystis aeruginosa; no cyanotoxins detected.
• Lake Okeechobee – Pahokee Marina Boat Ramp: Microcystis aeruginosa; trace level (0.61 parts per billion [ppb]) microcystins detected.
• Rodman Reservoir Dam – East: No dominant algal taxon; no cyanotoxins detected.
• Caloosahatchee River – Fort Myers Shores: Microcystis aeruginosa; trace level (0.11 ppb) microcystins detected.
• Bonita Lake – S Shore: Oedogonium sp.; trace level (0.23 ppb) cylindrospermopsin detected.
• Pioneer Lake – NE Shore: No dominant algal taxon; no cyanotoxins detected.
• Louise Lake – NW Lobe: No dominant algal taxon; trace level (0.36 ppb) microcystins detected.
• Lake Monroe – N Ramp: No dominant algal taxon; no cyanotoxins detected.
• St Johns River – at Lake Monroe Park: No dominant algal taxon; no cyanotoxins detected.
Results are pending for Lake Maitland – Kraft Azalea Garden; Lake Baldwin – Park Boat Ramp; and Lake Rowena – near NE corner.
On 5/22-5/24, South Florida Water Management District (SFWMD) staff collected five HAB response samples.
• C43 canal – S77 (upstream): Microcystis aeruginosa; trace level (0.40 ppb) microcystins detected.
• C43 Canal – S78 (upstream): Microcystis aeruginosa; 1.8 ppb microcystins detected.
• C23 Canal – S48 (upstream): No dominant algal taxon; no cyanotoxins detected.
• Lake Okeechobee – S354 (lakeside): Microcystis aeruginosa; estimated 1.1 ppb microcystins detected.
• Lake Okeechobee – S352 (lakeside): Microcystis aeruginosa; no cyanotoxins detected.
On 5/23-5/25, St. Johns River Water Management District staff collected nine HAB routine and two HAB response samples.
• Stick Marsh – North: No dominant algal taxon; no cyanotoxins detected.
• Blue Cypress Lake – Center: No dominant algal taxon; no cyanotoxins detected.
• Lake George – Center: Microcystis aeruginosa; no cyanotoxins detected.
• Ocklawaha River – 0.75 miles upstream of St. Johns River: No dominant algal taxon; no cyanotoxins detected.
• Lake Jesup – Center: Microcystis aeruginosa; no cyanotoxins detected.
• St. Johns River – Shands Bridge: No dominant algal taxon; no cyanotoxins detected.
• St. Johns River – Mandarin Point: No dominant algal taxon; no cyanotoxins detected.
• Doctors Lake – Center: No dominant algal taxon; trace level (0.29 ppb) microcystins detected.
Results are pending for Lake Monroe – Center; St. Johns River – downstream from Lemon Bluff boat ramp; and Crescent Lake – mouth of Dunns Creek.
On 5/25, Highlands County staff collected two HAB response samples at Lake Istokpoga – near C410 and Lake Bonnet – Boat Ramp. Sample results are pending.
Last Week
On 5/18, DEP staff collected HAB response samples from 14 sites.
• Lake Apthorpe – Boat Ramp: Microcystis aeruginosa; trace level (0.10 ppb) microcystins detected.
• Platt Lake – East: No dominant algal taxon; no cyanotoxins detected.
• Lake Virginia – Dinky Dock: Microcystis aeruginosa; trace level (0.18 ppb) cylindrospermopsin detected.
• Lake George – North: Microcystis aeruginosa; estimated 1.8 ppb microcystins detected.
• Park Lake – W Shore: No dominant algal taxon; trace level (0.23 ppb) microcystins detected.
• Lake Osceola – Canton Ave: Microcystis aeruginosa; no cyanotoxins detected.
• Peace River – Crews Park Boat Ramp: Microcystis aeruginosa; estimated 1.1 ppb microcystins detected.
• Lake Seminole – Boat Ramp: No dominant algal taxon; no cyanotoxins detected.
• Peace River – Brownville Park Boat Ramp: Microcystis aeruginosa; trace level (0.81 ppb) microcystins detected.
• Sunset Lake – W Shore: No dominant algal taxon; no cyanotoxins detected.
• Lake Rowena – near NE Corner: Microcystis aeruginosa; estimated 3.3 ppb microcystins detected.
• Lake Kinsale – East End: Oedogonium sp. and Calothrix sp. co-dominant; no cyanotoxins detected.
• Blue Lake – Western Shore: No dominant algal taxon; no cyanotoxins detected.
• Lake Minnehaha – E Dock: Microcystis aeruginosa; no cyanotoxins detected.
On 5/17, SFWMD staff collected a HAB response sample at the S352 Structure (lakeside). No dominant algal taxon and no cyanotoxins were detected.
Results for completed analyses are available at FloridaDEP.gov/AlgalBloom.
This is a high-level summary of the sampling events for the reported week. For all field visit and analytical result details, please refer to the complete algal bloom map with data table by clicking the “Field and Lab Details” Quick Link from the Algal Bloom Dashboard. Different types of blue-green algal bloom species can look different and have different impacts. However, regardless of species, many types of blue-green algae can produce toxins that can make you or your pets sick if swallowed or possibly cause skin and/or eye irritation due to contact. We advise staying out of water where algae is visibly present as specks or mats or where water is discolored pea-green, blue-green or brownish-red. Additionally, pets or livestock should not come into contact with algal bloom-impacted water or with algal bloom material or fish on the shoreline.

An interactive version of the above map with detailed sampling is available at FloridaDEP.gov/AlgalBloom. Or you can click on the map.
Blue-Green Algae Sampling Maps
Results for completed analysis are available at FloridaDEP.gov/AlgalBloom.
For detailed breakdowns of blue-green algae sampling across the state, visit the state Department of Environmental Protection.

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.



Bob Rountree is a beach bum, angler and camper who has explored Florida for decades. No adventure is complete without a scenic paddle trail or unpaved road to nowhere. Bob co-founded FloridaRambler.com with fellow journalist Bonnie Gross 12 years ago.