PBS and NPR for Southwest Florida
Play Live Radio
Next Up:
0:00 0:00
Available On Air Stations

Water Quality Report: Lee DOH issues blue-green algae alert

The Florida Department of Health in Lee County has issued a Health Alert for the presence of harmful blue-green algal toxins in Caloosahatchee River - Fort Myers Shores.
The Florida Department of Health in Lee County has issued a Health Alert for the presence of harmful blue-green algal toxins in Caloosahatchee River - Fort Myers Shores.


The Florida Department of Health in Lee County has issued a Health Alert for the presence of harmful blue-green algal toxins in Caloosahatchee River - Fort Myers Shores.

This area is in response to a water sample taken on May 23. The public should exercise caution in and around Caloosahatchee River -- Fort Myers Shores.

Residents and visitors are advised to take the following precautions:

  • Do not drink, swim, wade, use personal watercraft, water ski or boat in waters where there is a visible bloom.
  • Wash your skin and clothing with soap and water if you have contact with algae or discolored or smelly water.
  • Keep pets away from the area. Waters where there are algae blooms are not safe for animals. Pets and livestock should have a different source of water when algae blooms are present.
  • Do not cook or clean dishes with water contaminated by algae blooms. Boiling the water will not eliminate the toxins.
  • Eating fillets from healthy fish caught in freshwater lakes experiencing blooms is safe. Rinse fish fillets with tap or bottled water, throw out the guts and cook fish well.
  • Do not eat shellfish in waters with algae blooms.



Just a few weeks ago, the many media accounts of the thousands of tons of smelly, brown algae set to wash ashore on Southwest Florida’s beaches, any day, were very much the same: gloom and doom.

The Great Atlantic Sargassum Belt, as it came to be known, is a 5,000-mile-long mat of an ecosystem that was going to float its way to Southwest Florida’s beaches and coat the sand in feet-thick, stinky, brown, thick, algae.

It was to be a cruel, post-Ian, trick of nature.

Hurricane Ian’s legacy

Hurricane Ian in September destroyed billions of dollars worth of homes and businesses, cars and trucks, personal belongings, and cherished photos. Power was out for weeks in places. Hurricane debris was piled along the roads from Marco Island to Sarasota as trash removal firms from across America were hired to collect it all. Some businesses never reopened, and some people lost their jobs.

The after-shocks of Hurricane Ian went on for months. All the nutrients washed into the Gulf of Mexico fed red tides that were back-to-back-to-back-to-bac … well, you get my point. Related fish kills washed tons of bloating, smelly carcasses ashore and hard-working crews wiped the beaches clean. Soon after, a new red tide did the same thing. Rinse and repeat, for nearly seven months.

Finally, in late March, the red tides became less frequent and less. Without the strong red tides, fish kills declined quickly. The acrid odor of the red tide in the air mixed with the smell of rotting fish carcasses waned.

For beach-goers, the sandy shores started smelling like salt air once again. For beach-front business owners, people returning to the shore meant customers would be back for ice cream, souvenirs, food and drink, boat rentals, and parasail rides.

Life was going to be a beach once again.

Then, The Great Atlantic Sargassum Belt hit the news:


Huge seaweed bloom that can be seen from space threatens Florida beaches

“A giant seaweed blob so large it can be seen from space is threatening to transform beaches along Florida’s Gulf coast into a brown morass, scientists say. The 5,000-mile-wide sargassum bloom — believed to be the largest in history at twice the width of the continental US — is drifting ominously toward the Sunshine State”.


Massive seaweed blob heads to Florida, threatens to cover beaches

“A giant blob of seaweed, spanning 5,000 miles and weighing an estimated 6.1 million tons, threatens to blanket Florida beaches and Caribbean islands with smelly piles of decaying brown goop.”


A giant seaweed blob is washing up on Florida shores. What is sargassum?

“Last year, large amounts of sargassum washed ashore on Florida beaches, such as Miami, in July, according to CBS Miami. This year, images from Miami Beach show the brownish seaweed already creating a barrier between the sandy beach and the shoreline.”

Dodged a seaweed invasion?

Despite at least one story published on the web and broadcast on the radio that cast doubt on whether the doomsayers were correct, little else was out there for news consumers in Southwest Florida but those near-apocalyptic-sounding stories about the incoming sargassum invasion.

Sargassum did pile up on some islands in the Florida Keys and up the state's East Coast.

Turns out, however, except for the occasional pile almost small enough to be picked up by hand (don’t do that: remember those stingy creatures?), the sargassum “blob,” as it has also been called, is floating right on by Southwest Florida and currently headed toward Texas.

What’s that you say? A near miss? We finally got a break?

There is still a chance some of the sargassum could wind up here, but it’s looking as if The Great Atlantic Sargassum Belt will continue to float due west.

Sorry, Texas.


In the most recent water quality testing the red tide organism, Karenia brevis, was detected in 30 samples collected from Florida’s Gulf Coast, which is down from more than 100 positive samples just a few months ago.

Enough of the organism to create full-fledged blooms that often discolors the water was not found.

In Southwest Florida, K. brevis was observed at background-to-low concentrations in Sarasota, Charlotte, and Lee counties. Offshore of Collier County testing also found low amounts of the organism.

Reports of fish kills suspected to be related to red tide were received from Sarasota County, as were a spate of reports about respiratory irritation.

What is red tide?

Red tide is one type of harmful algal bloom caused by high concentrations of the toxic dinoflagellate K. brevis, which is a type of microscopic algae found in the Gulf of Mexico. Red tide typically forms naturally offshore, commonly in late summer or early fall, and is carried into coastal waters by winds and currents. Once inshore, these opportunistic organisms can use nearshore nutrient sources to fuel their growth. Blooms typically last into winter or spring, but in some cases, can endure for more than one year.

Is red tide harmful?

K. brevis produces potent neurotoxins that can be harmful to the health of both wildlife and people. Wind and wave action can break open K. brevis cells and release toxins into the air.

This is why you should monitor conditions and stay away from beaches where red tide is in bloom. People in coastal areas can experience varying degrees of eye, nose, and throat irritation during a red tide bloom.

Some individuals with chronic respiratory conditions like asthma or chronic lung disease will experience more severe symptoms. Red tide toxins can also affect the central nervous system of fish and other marine life, which can lead to fish kills.

What causes red tide?

A red tide bloom develops naturally, but recent studies have discovered mankind's infusion of other nutrients such as lawn fertilizer into the mix can make the red tide last longer or get stronger.

But no one factor causes the development of a red tide bloom, although marine scientists at several research institutes and universities have ongoing programs to figure out what the catalysts.


The most recent sampling by the Lee County Environmental Lab found elements related to blue-green algae at the Alva Boat Ramp as visible specks on the surface and in the water column, but no surface patches of algae.

Similar conditions were present upstream of the Franklin Locks and at the Davis Boat Ramp as streaks with wind-driven accumulation along the seawall.

Recent satellite imagery from Lake Okeechobee showed moderate-to-high bloom potential over 100 square miles in the southern portion as well as in Fisheating Bay.

What is blue-green algae?

Blue-green algae, also known as cyanobacteria, are a group of organisms that can live in freshwater, saltwater or brackish water. Large concentrations, called blooms, can change the water color to blue, green, brown, orange or red. Some cyanobacterial blooms can look like foam, scum, or mats on the surface of freshwater lakes and ponds. As algae in a cyanobacterial bloom die, the water may smell bad

Is blue-green algae harmful?

Different types of blue-green algal bloom species can look different and have different impacts. However, regardless of species, many types of blue-green algae can produce toxins that can make you or your pets sick if swallowed or possibly cause skin and eye irritation.

The Florida Department of Environmental Protection advises staying out of water where algae is visibly present as specks or mats or where water is discolored. Pets or livestock should not come into contact with algal bloom-impacted water or with algal bloom material or fish on the shoreline. If they do, wash the animals immediately.

What causes blue-green algae?

Blue-green algae blooms occur when the algae that are normally present grow in numbers more than normal. Within a few days, a bloom can cause clear water to become cloudy. Winds tend to push some floating blooms to the shore where they become more noticeable. Cyanobacterial blooms can form in warm, slow-moving waters that are rich in nutrients. Blooms can occur at any time, but most often occur in late summer or early fall.

If any major type of water quality alert is issued, you can find the details here in WGCU’s Water Quality Report.

Environmental reporting for WGCU is funded in part by VoLo Foundation, a non-profit with a mission to accelerate change and global impact by supporting science-based climate solutions, enhancing education, and improving health. 

Sign up for WGCU's monthly environmental newsletter, the Green Flash, today.

WGCU is your trusted source for news and information in Southwest Florida. We are a nonprofit public service, and your support is more critical than ever. Keep public media strong and donate now. Thank you.