News

By Dr. Beth Brady, Director of Science and Conservation

Manatees face a variety of threats each year that can lead to death, including red tide, collisions with watercraft, cold stress, and natural causes. In addition to documenting the number of carcasses observed each year, the Florida Fish and Wildlife Conservation Commission (FWC) conducts necropsies—autopsies for animals—on selected manatees to determine the cause of death. While not every manatee is necropsied, these data are still essential for understanding the primary threats to manatees and guiding conservation and management efforts.

In 2025, FWC documented 632 manatee deaths, below the five-year average of 731 but higher than totals recorded in 2023 (555) and 2024 (565). These losses were attributed to a colder winter, a red tide bloom, elevated calf mortality, and ongoing watercraft-related mortality.

Cold stress claimed 33 manatees. Despite their large size, manatees have only a thin layer of blubber, providing limited insulation. When water temperatures fall below 68°F, manatees must seek warm-water refuges. Prolonged exposure to cold can be fatal, reducing blood flow to the skin and causing sores. Their metabolism slows to conserve energy, making it difficult to eat, stay hydrated, and fight off disease.

Red tide was responsible for 50 deaths in Lee County (classified under Natural: Other by FWC). Red tide is caused by a naturally occurring marine plankton, or microscopic algae, called Karenia brevis, which is most common in the Gulf. This plankton produces neurotoxins called brevetoxins, which may be inhaled or ingested, causing seizures that often result in the manatee drowning.

Calf mortality included 136 perinatal deaths in 2025. Calves under 5 feet in length fall into the perinatal category, which includes deaths from cold stress, stillbirth, orphaning, or other causes. Many perinatal deaths occurred in the Indian River Lagoon, where manatee reproduction has rebounded since improved nutritional conditions in 2023. Some increase in calf deaths is expected with more births, inexperienced first-time mothers, or females still recovering from past malnutrition. Encouragingly, numerous live calf sightings suggest there is reproductive recovery in this region.

Collisions with watercraft remain a significant threat, accounting for 25% of necropsied deaths in 2025 (98 animals). Manatees are slow-moving, graze on grass in shallow water, and must surface to breathe, making them highly vulnerable to boats, and nearly every living manatee bears propeller scars. Boaters can help protect manatees by obeying posted speed zones, reviewing local boater guides, staying alert for signs of manatees, such as a snout, back, tail, flipper, or water swirls, operating in marked channels, avoiding shallow areas and seagrass beds, and maintaining a distance of at least 50 feet when observing manatees.

If you encounter a manatee in distress or find a deceased animal, call FWC at 1-888-404-3922. Additional information regarding the 2025 mortality records is available on FWC’s website at myfwc.com.