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Red Tide Current Status

Daily Sample Map
This map contains the last eight days of sampling and is updated daily at 5 p.m.
Please be sure to click on individual dots for sampling details.

Red Tide Status Update for September 17, 2021

Current Conditions

A patchy bloom of the red tide organism, Karenia brevis, persists along Florida’s Gulf Coast. Over the past week, K. brevis was detected in 44 samples. Bloom concentrations (>100,000 cells/liter) were observed in 12 samples: three in and offshore of Pasco County and nine in and offshore of Pinellas County. Additional details are provided below.

  • In Southwest Florida over the past week, K. brevis was observed at low to high concentrations in and offshore of Pinellas County, background to low concentrations in Manatee County, background to low concentrations in Sarasota County, background concentrations in Charlotte County, and background and low concentrations in and offshore of Lee County. For additional information, view the Southwest Coast report and map.
  • In Northwest Florida over the past week, K. brevis was observed at background concentrations in Bay County, background concentrations offshore of Hernando County, and very low to medium concentrations in and offshore of Pasco County. For additional information, view the Northwest Coast report and map.
  • Along the Florida East Coast over the past week, K. brevis was not observed. For additional information, view the East Coast report and map.

Charlotte Harbor

Over the past several days, red discolored water has been documented from upper (i.e., northeast) Charlotte Harbor. Sampling by FWRI has confirmed high cell concentrations (>1 million cells per liter) of the dinoflagellate Tripos hircus (previously known as Ceratium hircus). This species is not known to produce toxins. We continue to monitor this bloom directly and with support from our partners.

Fish Kills

Fish kills suspected to be related to red tide were reported on the Florida Gulf Coast offshore of Citrus and Pasco counties and in Pinellas, Sarasota, and Lee counties over the past week. For more details, please visit:

Respiratory Irritation

Respiratory irritation suspected to be related to red tide was reported over the past week in Southwest Florida in Pinellas, Sarasota, and Lee counties. For recent and current information at individual beaches, please visit and for forecasts that use FWC and partner data, please visit


Forecasts by the USF-FWC Collaboration for Prediction of Red Tides for Pinellas to northern Monroe counties predict net southern movement of surface waters and variable movement of subsurface waters over the next 3.5 days.

Piney Point Updates

FWC-FWRI is working closely with the Florida Department of Environmental Protection (FDEP) and other partners on the Piney Point response effort. Status updates and results are posted on the Protecting Florida Together website ( and on the Tampa Bay Estuary Program website (

Red Tide Status Map (September 17, 2021)

View a larger map (September 17, 2021).

To see detailed information on this week's samples, view the current Statewide Google Earth map for September 17, 2021.

By using Google Earth, you can zoom in to specific locations and click on stations to see detailed information, including sample date and cell concentration. You must have Google Earth installed on your computer to view this map; the software can be downloaded from the Google Earth website.

The next complete status report will be issued on Friday, September 24th. Please check our daily sampling map which can be accessed from the top of this page.

Archived status maps can be found in our Flickr gallery. Previous regional status reports and maps can be found on our red tide resources page.

Latest Red Tide Status Report Available by Phone

Call 866-300-9399 at any time from anywhere in Florida to hear a recording about red tide conditions throughout the state. Callers outside of Florida can dial 727-502-4952. Standard calling charges apply.

Reports are updated on Friday afternoon except during holidays, in which case the report will be released on the closest day. Additional information, if available, is provided on Wednesday afternoon. To receive an e-mail when the current status has been updated, visit our subscription area.

Additional Information

For additional information about red tide and the current red tide bloom, including information on how to report a fish kill or other wildlife effects, consult health authorities about human exposure, or locate other resources, visit our Red Tide-Related Hotlines and Information Sources article.

Blue-Green Algae Bloom Information

Additional information regarding the current status of algal blooms in South Florida is being consolidated and posted on the Florida Department of Environmental Protection’s website:

Key for Results

Description K. brevis abundance Possible effects (K. brevis only)
NOT PRESENT- BACKGROUND background levels of 1,000 cells or less no effects anticipated
VERY LOW > 1,000 - 10,000 cells/L possible respiratory irritation; shellfish harvesting closures when cell abundance equals or exceeds 5,000 cells/L
LOW > 10,000 - 100,000 cells/L respiratory irritation; shellfish harvesting closures; possible fish kills; probable detection of chlorophyll by satellites at upper range of cell abundance
MEDIUM > 100,000 - 1,000,000 cells/L respiratory irritation; shellfish harvesting closures; probable fish kills; detection of surface chlorophyll by satellites
HIGH > 1,000,000 cells/L as above, plus water discoloration