Red Tide at Siesta Key Today

What red tide is

Red tide on Florida’s Gulf coast is a bloom of Karenia brevis, a single-celled alga that lives offshore year-round and occasionally multiplies into concentrations dense enough to discolour the water. It produces brevetoxins, which kill fish and — when wind and surf break the cells open — drift ashore as an aerosol that makes people cough. Blooms usually start 10 to 40 miles offshore and are carried inshore by currents and wind, which is why one beach can be miserable while the next one up the coast is fine.

Around Siesta Key, a bloom matters for more than the beach: it can shut down the snook and spotted seatrout bite for weeks, and dead fish along Big Sarasota Pass & the Gulf are usually the first sign that one has moved in.

What the levels mean

Florida Fish & Wildlife counts cells per litre in each water sample and sorts the result into five bands. These are the state’s own categories, not ours.

Checking the beach before you drive

Samples are collected every few days, not continuously, so the honest way to read this page is “here is what the water tested at recently.” Conditions can change in a day. Two things fill the gap: wind direction — an onshore breeze carries irritation to the beach while an offshore one holds it out — and other people. If a bloom is inshore, the local fishing groups know before any official map does.

Rule of thumb: if you get to the beach and start coughing within a few minutes, or the water looks the colour of weak tea with dead bait along the wrack line, that is red tide regardless of what the last sample said.

Red tide at Siesta Key: common questions

Is there red tide at Siesta Key right now?

As of the most recent Florida Fish & Wildlife samples (Jul 28), red tide near Siesta Key is not detected. No Karenia brevis above background levels in the latest samples. No red tide effects expected.

How often is red tide data for Siesta Key updated?

Florida Fish & Wildlife publishes the last eight days of water samples and refreshes the feed daily. This page reads that feed hourly, so it reflects the newest sample as soon as the state posts it. Sampling itself happens every few days, not continuously.

Can you swim or fish at Siesta Key during red tide?

At low concentrations most people are fine, though anyone with asthma or a respiratory condition should be careful near the surf. At medium and high levels expect coughing on the beach and dead fish in the water. Fish caught alive in a bloom are generally considered safe to eat if filleted, but never eat dead or distressed fish, and do not harvest shellfish from closed areas.

Why does one beach have red tide and the next one doesn't?

Blooms are patchy and move with wind and current. A concentration sitting a few miles offshore can be pushed onto one stretch of Big Sarasota Pass & the Gulf by an onshore breeze while the beach around the corner stays clear, then reverse the next day when the wind turns.