| By Natalie Mousa
The National Oceanic and Atmospheric Administration (NOAA) has declared the Atlantic Florida Manatee crisis as an “Unusual Mortality Event” (UME), due to the significant die-off of the manatee population, demanding an immediate response. The FWC records show that more than 5 manatee deaths have been recorded every day since January 1, 2021.
West Indian Manatee
The West Indian Manatee, known by its scientific name as the Trichechus manatus, is made up of two subspecies; the Antillean Manatee (Trichechus manatus manatus) and the Florida Manatee (Trichechus manatus latirostris).3
Map of the West Indian manatee’s range. Jane Cooke, USFWS.
The West Indian Manatees can be found throughout the Caribbean basin, including the southeastern United States, eastern Mexico, eastern Central America, northeastern South America, and the Greater Antilles. The U.S. Fish and Wildlife Services (FWS) has classified the West Indian Manatee as threatened.
The Florida Manatee spends its time around the warm Floridian waters. This is because they cannot tolerate temperatures below 68 degrees Fahrenheit for extended periods of time. When temperatures drop, the Florida Manatee are condensed around the Florida Peninsula.
There are about 6,300 manatees in Florida, according to the U.S. Fish and Wildlife Service. With 819 recorded deaths as of June 4, the number equates to over 10 percent of the estimated manatees population, with potential to grow as the year goes by. The map below highlights the critical areas for the manatees in Florida.
Critical Habitat for the Florida manatee, Jane Cooke, USFWS
Why are Manatees Dying?
Manatees are nicknamed “sea cows” due to their eating habits. They are herbivores that feed off seagrass and other aquatic plants. The manatees help keep the seagrass healthy. By grazing on the seagrass and giving it a trim, it stimulates growth.
Over the years, the seagrass quality has been declining throughout Florida. This is due to a decrease in overall water quality, which is attributed to runoff from fertilizers, sewage and septic leaks, and increasing algae blooms (which kill seagrass).
Runoff from fertilizers and sewage and septic leaks cause an increase in nitrogen and phosphorus in the water. Jaclyn Lopez, Florida director for the Center for Biological Diversity stated that this influx “serves as a steroid for algae,” increasing its growth.4 The algae soaks up all the oxygen in the water, creating an imbalance in the ecosystem, along with shading out sunlight from the seagrass.
Lopez emphasized that “it’s fair to call it a crisis. It’s not hyperbole when you see hundreds of manatees dying like this.”5 The COVID-19 pandemic only delayed scientists from seeing and noticing these deaths earlier.
The Indian River Lagoon, a 156-mile estuary along Florida’s Atlantic coast, has lost tens of thousands of acres of seagrass. The St. Johns River Water Management District has found that since 2009, close to 60 percent of the seagrass in the Indian River Lagoon has disappeared. Algae bloom is the cause of 90 percent of deaths of manatees in the Indian River Lagoon.6
Steve Murawski, a fisheries biologist and marine ecologist at the University of South Florida’s College of Marine Science, stated that “the increase in algal (algae) blooms are related to coastal degradation and the increase in nutrients.” 6 The water pollution has gotten so bad that it is choking off the seagrass from maintaining its nutrient levels, thus leading to manatee starvation.
Manatees Legal Protection
Manatees are protected under the Marine Mammal Protection Act in 1972 (MMPA), which Congress passed due to increasing concerns among scientists and the public that significant declines in some species of marine mammals were caused by human activities.7
One of the three federal entities responsible for implementing the MMPA is the U.S. Fish and Wildlife Service, which is responsible for the protection of walrus, manatees, sea otters, and polar bears.
The Endangered Species Act was enacted under the Nixon Administration in hopes of protecting the species most vulnerable. While the NOAA and the FWS share responsibility for implementing the ESA, the FWS is responsible for most terrestrial and freshwater species including manatees.8
Who Else is Affected?
Manatees are known as sentinel species. This means that they serve as health indicators for the rest of the ecosystem they are a part of. If the number of manatees decline, it is a health indicator of the other animals and plants they are surrounded by.9
How Can You help?