Beachgoers Beware:
Red Tide Outbreaks in Florida

manatee surfacing to breathe
Manatees are mammals and must surface to breathe. They can get sick or die from breathing a concentrated aerosol form of the red tide toxin found in the supersaturated layer of air just above the water's surface. (Photo © David R. Schrichte)

By Kelly Novic
Staff Biologist,
Save the
Manatee Club

Fall in Florida often brings with it red tide, and this year is proving to be no exception. There are currently several blooms across the state and it is important for beachgoers to recognize the signs of red tide outbreaks and the symptoms of red tide toxicity for both humans and manatees. If you see a manatee you suspect of being sick or injured, please report it right away

Report Sick or Injured Manatees
A manatee suffering from the effects of red tide may exhibit muscle twitches, lack of coordination, labored breathing, and an inability to maintain body orientation. If rescued in time, most manatees can recover from the effects of red tide toxicity, so please report a sick manatee immediately to the Florida Fish and Wildlife Conservation Commission (FWC) Wildlife Alert Hotline at 1-888-404-FWCC (3922), #FWC or *FWC on your cellular phone, or use VHF Channel 16 on your marine radio. To report a stranded manatee, dolphin, whale, or sea turtle, please call the MOTE Marine Lab Stranding Investigations Program pager at 941-988-0212.

About Red Tide
Red tide is actually a bloom of a small microorganism known as Karenia brevis, which produces toxins that affect vertebrate nervous systems. Although always present at low concentrations offshore, Karenia brevis can occasionally generate large dense blooms along the coastline known as “Florida red tide”.

Red tide outbreaks are characterized by a red discoloration of water (though waters can also be brown, green, or yellow). Red tide causes human respiratory distress, shellfish poisoning, and can result in the deaths of fish, turtles, marine mammals such as manatees, and other animals.

red tide in Florida
Florida red tide bloom of Karenia brevis. (Photo courtesy of Karen Steidinger, Florida Fish & Wildlife Conservation Commission.)

Red tide toxins can accumulate in waters, along beaches, and can be released into the air as wave action breaks apart cells of the microorganism. Red tide toxicity may occur by inhalation of toxins as well as by ingestion. Both humans and manatees are susceptible to toxic inhalation effects. Symptoms of inhalation toxicity in humans include respiratory irritation, stinging eyes and nose, and an accompanying dry, choking cough.

Toxicity induced by ingestion can occur in humans after eating contaminated shellfish. Individuals can then suffer from the debilitating, but usually not fatal, neurotoxic shellfish poisoning (NSP). Symptoms of NSP include mouth numbness, poor coordination, abdominal pain, and tingling of the mouth, arms, and legs. Ingestion-induced toxicity in manatees can occur after eating contaminated seagrasses, a major food source for manatees, or even tunicates, small filter-feeding animals that live among seagrass beds.

Check before traveling to a beach to make sure that there are no active blooms in the area. The Red Tide Status Line can give you this information: 866-300-9399 (toll-free inside Florida only); 727-552-2448 (outside Florida). Or you can visit the FWC website for current red tide status across the state.

If you experience any harmful effects or symptoms associated with exposure to aquatic toxins or harmful algae, contact the Marine and Freshwater Toxins Hotline: (888) 232-8635 (toll free).

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