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When red tide is present, a sign will be posted to inform the public and provide information. [DOC 13KB]

Example of Red Tide sign [DOC 13KB]

Red Tide

Main Administrative Office

Protect yourself and family against Florida Red Tide exposure. Please read signage when you go to area beaches. Not all beaches are affected. Conditions can change daily. Check the Mote Marine twice daily Beach Conditions Report at or call 1-941-BEACHES

Red Tide Observed Effects at Monitored Beaches
LocationDateCell Count /mL
Longboat Key10/11/20211,230
Bird Key Park10/11/2021240
North Lido Beach10/11/20211,240
Lido Beach (Casino)10/11/2021938
South Lido Park10/11/20211,312
Siesta Key10/11/20211,874
Turtle Beach10/11/20212,732
Nokomis Beach10/11/20213,980
North Jetty10/11/20216,670
Venice Beach10/11/2021952
Service Club Park10/11/2021376
Venice Fishing Pier10/11/202146
Brohard Beach10/11/202134
Caspersen Beach10/11/202181
Manasota Beach 10/11/202110,910
Blind Pass 10/11/20216,070

Table Data Last Modified: Wed Oct 13, 2021 16:46:05 EDT

DescriptionKarenia brevis cells/MLPossible Effects (Karenia brevis only)
Not present in background0 - 1None Anticipated.
Very Low> 1 - 10Possible respiratory irritation; shellfish harvesting closures > 6 cells/mL.
Low> 10 -< 100Respiratory irritation; possible fish kills and bloom chlorophyll probably detected by satellites at upper range.
Medium> 101 -< 1,000Respiratory irritation and probably fish kills.
High> 1,000As above plus discoloration

Table Data Last Modified: Tue Feb 12, 2019 14:52:12 EST

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Red tides have been documented along Florida's gulf coast since the 1840’s.

  • The Florida red tide organism, Karenia brevis, produces a toxin that may kill marine animals and affect humans.
  • A red tide bloom is a higher-than-normal concentration of a microscopic alga (plant-like organisms).
It is important to realize that many people still enjoy the beaches during red tides. Respiratory irritation and dead fish are not always present.People may experience respiratory irritation (coughing, sneezing, and tearing) when the red tide organism is present along a coast and winds blow its aerosol onshore.
  • People with severe or chronic respiratory conditions are advised to avoid red tide areas.
  • Generally, symptoms are temporary.
  • Swimming in waters with red tide is safe for most people.
  • However, red tide may cause some people to suffer from skin irritation and burning eyes.
  • If you experience irritation, get out of the water and thoroughly wash.
  • For more information regarding red tide, visit our Links to our Partners 
A Red Tide Rack Card [PDF 2.36MB] with useful facts and tips about red tide is available.