Southwest Florida scientists tracking changes in red tide algae counts

Siesta and Turtle beaches among those with highest concentrations mid-week

Mote Marine Laboratory offers beach reports online. Image from the website on the morning of Sept. 29, 2016
Mote Marine Laboratory offers beach reports online. Image from the website on the morning of Sept. 29, 2016

Water samples collected by the Florida Department of Health on Sept. 26 along Sarasota County’s coastline and analyzed by Mote Marine Laboratory showed medium to high cell counts of the naturally occurring Florida red tide algae, Karenia brevis, in all 16 locations the department checks, Mote spokeswoman Kaitlyn Fusco reported in a Sept. 28 news release.

Five locations had high concentrations of the algae, she pointed out: Siesta Beach, Turtle Beach, Nokomis Beach, Venice North Jetty and Manasota Beach.

As of the evening of Sept. 27, Mote’s Beach Conditions Reporting System had noted respiratory irritation and dead fish at all beaches in Sarasota and Manatee counties except for Manatee Beach, Fusco wrote. Venice North Jetty, Lido Beach, Venice Beach and Nokomis Beach reported slight respiratory irritation, while Siesta Key and Coquina Beach reported moderate respiratory irritation, and Manasota reported intense respiratory irritation, she added.

At Siesta Key Beach on Sept. 29, Mote’s beach conditions report showed moderate respiratory irritation early in the morning, declining to “Slight” by mid-morning, The Sarasota News Leader found. The notation for the count of dead fish was “Some.”

The more southerly beaches in the county also were reporting respiratory irritation at the “Slight” level. However, on Lido Key by mid-morning, the level was “Moderate,” with a heavy concentration of dead fish. Reports for the Venice and Nokomis beaches also showed the “Heavy” notation for dead fish.

Karenia braves is a single-cell organism. Image from FWC via Flickr
Karenia brevis is a single-cell organism. Image from FWC via Flickr

Mote Marine Laboratory scientists and others are continuing to monitor the elevated levels of Karenia brevis along the Southwest Florida coastline, Fusco wrote. Mote encourages the public to follow online updates.

K. brevis, the single-celled, harmful algae that causes Florida red tide, occurs naturally in the Gulf of Mexico at concentrations considered to be ‘background,’” Fusco explained. “During bloom conditions, concentrations can increase to ‘very low,’ ‘low,’ ‘medium’ and ‘high’ levels, she added. “When Florida red tide algae cells are present in concentrations elevated above normal ‘background’ levels, people can experience varying degrees of eye, nose, and throat irritation while at the shore or on the water,” Fusco pointed out in the release. When a person leaves an area experiencing red tide conditions, the person’s symptoms usually go away, she added. People with asthma, chronic obstructive pulmonary disorder (COPD) or other chronic respiratory conditions are cautioned to avoid areas with active red tide events, Fusco advised. “Red tide concentrations elevated to levels ‘low’ or above can cause respiratory irritation and may also kill fish,” she wrote. “Many factors, including algae distribution, currents and winds, can determine whether effects are noticeable.”

Blooms of Florida red tide can be very patchy, with background to high concentrations occurring in close proximity to one another. Therefore, effects may be noticeable on one beach but not on a nearby beach, she pointed out.

Red tide monitoring in Florida is accomplished through a unique collaboration among the Florida Fish and Wildlife Conservation Commission’s Fish and Wildlife Research Institute, the Florida Department of Agriculture and Consumer Services (FDACS), the Florida Department of Health, Mote Marine Laboratory, the University of South Florida, county agencies, other private nonprofit agencies and citizen volunteers, Fusco added.

The Florida Fish and Wildlife Conservation Commission (FWC) posts red tide status reports on Fridays, along with mid-week reports on Wednesdays when information is available, Fusco noted. To view these statewide reports and track red tide blooms, visit

Additional red tide resources

The Florida Fish and Wildlife Conservation Commission provided this data about the red tide event on Sept. 28. Image courtesy FWC
The Florida Fish and Wildlife Conservation Commission provided this data about red tide on the west coast of Florida on Sept. 28. Image courtesy FWC

Fusco offered other resources for the public to check:

To report fish kills, contact the FWC Fish Kill Hotline at 800-636-0511 or submit a report online.

Based on statewide results, the National Oceanic and Atmospheric Administration provides forecasts of potential respiratory irritation:

Mote’s Beach Conditions Reporting System provides shoreline observations as often as twice daily:

Red tide and human health: information and rack cards from the Florida Department of Health:

FWC’s red tide offshore monitoring program — a way for volunteers to help:

FWC-Mote Facebook page, Florida Red Tide and Other Harmful Algal Blooms: