Red tide: Check latest tests to see if it's safe to swim at your favorite Brevard County beach

Cheryl McCloud
Florida Today

Florida red tide occurs almost annually, especially along portions of the Gulf Coast, according to the National Ocean Service.

Brevard County is no stranger to the red tide algae, Karenia brevis. 

In October 2018, red tide rose to "high” levels in Brevard, Indian River and St. Lucie counties, according sampling by the Florida Fish and Wildlife Conservation Commission. The result? Fish kills and people avoiding the beaches.

At high enough concentrations, red tide can cause respiratory problems and skin irritations, among other symptoms.

The FWC regularly tests for red tide at several locations. The map updates every hour from data received from FWC. 

Can't see the map? 

What do the red tide concentration numbers mean?

  • Background: The level of Karenia brevis cells per liter of water is less than 1,000, which isn't expected to cause any ill effects. If levels exceed 1,000 cells per liter, people can experience respiratory irritation and shellfish harvesting may be closed. 
  • Medium: Levels range from 100,000 to 1 million cells per liter. At this concentration, fish start to die and satellites pick up the increase in chlorophyll at the water's surface. 
  • High: More than 1 million cells per liter. The water turns red and the marine death toll escalates.

So should you swim if red tide is present?

In cases involving severe or chronic respiratory conditions, like emphysema or asthma, the irritation can become serious. Most humans can safely swim in red tide, but it can cause skin irritation and burning eyes.

Respiratory irritation associated with blooms of Karenia brevis is usually temporary, but serious illness can occur in people with asthma, COPD or other respiratory diseases.

Some people who swim in red tide experience skin irritation and rashes, and some swimmers have reported eye irritation from the sea foam.

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