Florida
Toxic algae in Duval County lakes
25 lakes and waterways in Duval County have harmful algal bloom reports in Florida's official data. The most recent entry is for St Johns River: Florida's most recent sample from St Johns River, on 16 December 2025 at St. Johns River - Shands Bridge (20030157), found no visible bloom and no microcystin toxin was detected. St Johns River and Ortega River have had blooms in three or more years.
Lakes with bloom history
Newest report first. Each lake has its own page with the full history and what the results mean.
Other waterbodies with a report
These have one or two reports in a single year, which isn't enough history for a page of their own yet.
- Arlington River 2019
- Brown Lake Whatley Memorial Park Stream 2021
- Canal To Mill Cove 2020
- Dunn Creek 2021
- Julington Creek 2019
- Little Pottsburg Creek 2025
- Marco Lake 2019
- Miramar Creek 2020
- New Rose Creek 2025
- Ribault River 2025
- San Marco Lake Canal 2020
- Spoonbill Pond 2020
- St John's River Shoreline/Goodby's Creek 2018
- St Johns River Downtown Jacksonville 2019
- Sweetwater Lake 2018
- West Of Julington Creek Mouth 2017
- Willow Branch 2021
Source: Florida Department of Environmental Protection (DEP), official data, checked 24 October 2026. For today's conditions see the DEP Algal Bloom Dashboard. No report doesn't mean a lake is safe: most water is only tested occasionally.