Red Tide is Extremely Harmful to Manatees
Yes, manatees are severely affected by red tide, which can be fatal. The red tide organism common in the Gulf of Mexico, Karenia brevis, produces potent neurotoxins called brevetoxins that damage the manatees’ central nervous systems and can lead to seizures and drowning.
How Manatees are Exposed
Manatees can be exposed to brevetoxins in two primary ways:
- Ingestion: Manatees consume the toxins when they eat contaminated seagrass, which accumulates the brevetoxins during a bloom. The toxins can remain in the seagrass for weeks after a red tide has dissipated.
- Inhalation: When waves break, they can rupture the K. brevis cells and release the toxins into the air as an aerosol. Manatees inhale these airborne toxins when they surface to breathe.
Symptoms of Brevetoxicosis
Signs that a manatee is suffering from red tide poisoning (brevetoxicosis) include:
- Lethargy or weakness
- Facial twitching or tremors
- Abnormal swimming (e.g., swimming sideways or in circles)
- Inability to surface to breathe, which can lead to drowning
- Beaching in shallow water
- Seizures or paralysis
Impact and Mitigation
Red tide has caused extensive die-offs, with mass mortality events recorded in Florida in numerous years, including 1996, 2013, 2018, and 2021. In 2018, red tide was responsible for 288 manatee deaths.
If a manatee is found alive but in distress due to red tide exposure, trained biologists can move it to a critical care facility for stabilization and rehabilitation. Many manatees have recovered and been released back into the wild thanks to these rescue efforts.
How You Can Help
If you see a sick, injured, or dead manatee, you should immediately report it to the Florida Fish and Wildlife Conservation Commission (FWC) Wildlife Alert Hotline at 1-888-404-3922.
