How Red Tide Advisories Work on Collier County Beaches

Red tide is a bloom of Karenia brevis, a naturally occurring alga that has affected the southwest Florida coast for as long as there are records of it. It is most commonly a late summer and autumn problem here, though blooms have persisted into winter in some years and been absent in others.

Two things happen when a bloom moves inshore. Fish die and wash up along the tide line, and the toxin becomes airborne in sea spray, causing coughing, throat irritation and watering eyes in people on the beach. For most visitors that is unpleasant rather than dangerous. For anyone with asthma or a chronic respiratory condition it is a reason to stay away from the affected sand entirely.

The part worth knowing

Advisories are issued and lifted beach by beach, not for the whole coast. Florida's health department in Collier County posts alerts for specific beaches when sampling and observed conditions warrant, and lifts them the same way. Marco's beaches have been placed under advisory and cleared again within the space of a few weeks.

That granularity matters because blooms are patchy and wind-driven. An onshore breeze concentrates the effects; an offshore breeze clears the air within hours. One access point can be miserable while another a couple of miles along the same crescent is fine.

What to actually do

• Check current conditions on the morning you plan to go, not a week ahead. Any forecast beyond a few days is not worth much.
• Trust your eyes and throat. Dead fish along the wrack line and people coughing on the sand are the fastest indicators there are.
• Move rather than cancel. If the Gulf beach is affected, the estuary side, the Tigertail lagoon or an inland trip is usually unaffected.
• If you have a respiratory condition, take the advisories seriously and stay off the affected beach.
• Do not collect or eat dead fish or shellfish from an affected beach.

Blooms come and go. Most trips here are never touched by one, and the ones that are can usually be replanned by driving ten minutes.