A total of 841 manatee deaths were recorded by Florida’s Fish and Wildlife Commission between January 1 and July 2.
This means that in the first half of 2021, the mortality figure has surpassed the previous highest statewide number of 830 for the whole of 2013.
Most of the deaths are thought to have occurred during migration due to a loss of seagrass—a crucial food source for the animals.
Manatees, also known as sea cows, are large aquatic mammals often found in coastal waters.
In a note attached to the most recent manatee mortality data table, Florida’s Fish and Wildlife Research Institute (FWRI) said: “Unprecedented manatee mortality due to starvation was documented on the Atlantic coast this past winter and spring.
“Most deaths occurred during the colder months when manatees migrated to and through the Indian River Lagoon where the majority of seagrass has died off.”
The institute said the long-term health effects of “prolonged starvation” on surviving manatees are not yet known.
It also underscored the need to recognize boat strikes, or “watercraft-related mortality,” as an ongoing threat to manatee populations.
Of the 841 reported manatee deaths, 63 were reported to have involved a boat of some kind—slightly higher than the five-year average of 60.
The vast majority of deaths, 518, were not necropsied—a term referring to an autopsy performed on an animal. This marks a significant increase from the five-year average of 49 deaths not necropsied.
The reported death total of 841 is more than double the five-year average of 352. The rate of deaths have made headlines for months.
The U.S. Fish and Wildlife Service has confirmed that the manatee deaths are classed as an unusual mortality event (UME), meaning the deaths are unexpected, significant, and warrant an immediate response.
Experts have pointed to conditions in the Indian River Lagoon as a primary factor, namely the reduction in seagrass.
The seagrass reduction has been linked to human-caused pollution of waterways. This pollution, such as fertilizer runoff and sewage leaks, causes algal blooms to proliferate in the water.
These algal blooms prevent seagrass from growing because they take up oxygen and sunlight in the water.
Patrick Rose, an aquatic biologist and executive director of the Save the Manatee Club, told Newsweek in May: “The Indian River Lagoon (IRL) has experienced devastating losses of seagrasses wherein more than 90 percent of the seagrass biomass has been killed off by severe and repeated harmful algal blooms as the result of decades of nutrient pollution from human waste entering the IRL through the groundwater from leaching septic drain fields, poorly treated wastewater from municipal treatment facilities, and stormwater runoff containing fertilizers and other pollutants.”
Rose said Floridians can help by contacting their local, state and federal leaders to demand action, both to prevent pollution from happening in the first place and to call for a clean-up of existing pollution.
