Red Tide and Algal Bloom Status 2026

The panels above show the highest category each agency is reporting right now, with the time attached. The Florida Fish and Wildlife Conservation Commission publishes categorical cell counts from its statewide sampling, and NOAA publishes a separate beach level respiratory irritation forecast; both are reproduced as issued. When neither agency is reporting anything, the panels say so.

In the United States the phrase usually means a bloom of Karenia brevis, a marine alga of the Gulf of Mexico that produces brevetoxins. FWC states that blooms occur in the Gulf almost every year, generally in late summer or early fall, and that most blooms last three to five months. The toxins get into sea spray, which is why the first thing most people notice is a cough and burning eyes rather than anything in the water. The same name gets applied loosely to other blooms, including freshwater cyanobacteria, which are a completely different organism with a different toxin.

No, and this is the most common misunderstanding about it. FWC associates visible water discoloration only with its highest category, more than a million cells per litre. Shellfish harvesting closures start at 5,000 cells per litre, two hundred times lower, and respiratory irritation is possible from its very low band upward. Water that looks completely normal can still carry enough cells to close beds and make people cough.

The Florida Fish and Wildlife Conservation Commission publishes this wording: "Red tide can cause skin irritation, rashes, and burning/sore eyes. Do not swim in or around red tide." That is FWC's sentence, quoted, and FWC is the authority. Whether a specific beach is open on a specific day is decided by the local health department and the people posting signs at the access point.

Shellfish harvest closures are legal orders issued by state health and agriculture departments, they change without warning, and getting one wrong is a hospital matter. Each state page here names the office that issues them and its phone number. FWC's own published answer on commercially sold product is that "store-bought and restaurant-served shellfish are generally safe to eat during a bloom because the shellfish are monitored by the government for safety", which is about monitored commercial product and not about anything harvested recreationally.

It depends which bloom and which coast, which is why each state has its own page. For Florida, FWC states that blooms occur almost every year, generally in late summer or early fall, and that most last three to five months, so a Florida red tide often runs through the winter rather than the summer. For the western basin of Lake Erie, NWS Cleveland gives the bloom season as typically July to October. Pacific and Gulf of Maine biotoxin closures follow their own calendars, set by each state.

Red tide means a marine bloom, in the Gulf of Mexico usually Karenia brevis, which produces brevetoxins and causes respiratory irritation carried in sea spray. Blue-green algae means freshwater cyanobacteria such as Microcystis, which bloom in lakes and slow rivers and produce a different family of toxins. Different organisms, different water, different monitoring programmes. A status for one says nothing about the other, and the two get confused constantly because both turn water a strange colour.

Two live sources, both read directly in your browser with no server in between. The Florida Fish and Wildlife Conservation Commission publishes the last eight days of statewide Karenia brevis sampling from its HAB Monitoring Database, which holds records from 1953 to the present. NOAA's National Centers for Coastal Ocean Science publishes a beach level respiratory irritation forecast, released under a Creative Commons Zero public domain dedication. Everything else on these pages is quoted from the agency that said it, with a link.

No. FWC, NOAA and the state health departments publish official categories for harmful algal blooms, those categories carry health meaning, and these pages reproduce them as issued rather than adding a competing number. The only thing computed on these pages is which colour to paint a chip.