Thousands of acres of seagrass in Florida have died because of nutrient pollution that has caused algae blooms and left manatees without an adequate food source. Learn more about this issue, projects that are being undertaken, and ways you can help.

January 24, 2023

This page will be updated as new information becomes available. 

Preliminary 2022 manatee mortality statistics have been released, and a total of 800 manatees were recorded to have died in the state of Florida in 2022. While this number is down from 1,100 deaths in 2021, the number of deaths remains above the five-year average. The Florida Fish and Wildlife Conservation Commission and U.S. Fish and Wildlife Service have has resumed its supplemental feeding trial in Brevard County. Click to learn more from FWC, and read on for more information on the root cause of the unusual mortality event (UME) caused by harmful algal blooms in the Indian River Lagoon, how Save the Manatee Club has taken action, and what you can do.

Manatee Carcass Recovery Locations 2021
Note: data is preliminary. As of February 17, 2022, there were 1100 confirmed carcasses recovered in 2021.

Trouble for Manatees in the Indian River Lagoon

The Indian River Lagoon (IRL) stretches for 156 miles along Florida’s east central coast. There are more than 4,400 species of plants and animals — including manatees — that are found in the lagoon watershed. Unfortunately, as the direct result of human derelictions over many decades, the Indian River Lagoon has suffered a series of harmful algal blooms, leading to massive losses in seagrass coverage and, in turn, the recent deaths of a heart-rending number of manatees.

Manatees gathering at warm water locations such as powerplants along the IRL faced an additional threat during the 2020-2021 and 2021 – 2022 winter seasons because there was very little seagrass or vegetation for them to eat in the immediate vicinity. Traveling further for forage would mean deadly exposure to cold water, so the manatees ultimately choose to forgo feeding over dying from the cold. Between December 2020 and May 2021, there were 677 dead manatees reported on Florida’s east coast. In 2021, the U.S. Fish and Wildlife Service (FWS) declared an Unusual Mortality Event (UME) for manatees. A UME involves a significant die-off of any marine mammal population and demands immediate response.

Excessive human-produced nutrient pollution is a growing threat to all seagrass communities. When combined with the warming effects of climate change and sea level rise, these excess nutrients present an even greater danger to the future of seagrasses wherever they are found.

Emaciated Manatee Rescue
An emaciated manatee is rescued by the Florida Fish & Wildlife Conservation Commission.

Before the IRL can be functionally restored, it will be necessary to prevent new sources of nutrient pollution from entering the lagoon as well as strategically removing or sequestering legacy nutrients to make them unavailable as a source of new Harmful Algal Blooms (HAB). Ideally, seagrasses will begin to reestablish on their own, but the process may be facilitated through the restoration of filter feeding organisms and selective pilot seagrass restoration projects. Ultimately, we must reverse those conditions that lead to the loss of seagrasses in the first place if we are going to restore seagrasses.

In a healthy ecosystem, free-ranging manatee grazing makes seagrass communities more productive. Manatees have evolved along with seagrass communities for millions of years and crop the grasses rather than uprooting entire plants, which can actually stimulate the grasses to grow. The loss of seagrass in the IRL is largely due to persistent and recurring environmental events that have changed the ecosystem over time — especially from human sources of pollution, such as improperly-treated sewage, leaking septic systems, and fertilizers, together with stormwater runoff. All these factors combined have led to eutrophication that has resulted in frequent harmful algal blooms that blocked the light necessary for photosynthesis and resulted in the tragic loss of more than 90% of the seagrass biomass within the Indian River Lagoon.


What is Being Done to Help Malnourished Manatees?

Save the Manatee Club is part of a network of partners in the Manatee Rescue and Rehabilitation Partnership (MRP) who help rescue and rehabilitate sick or injured manatees, which includes severely malnourished manatees. Together with partners in the MRP, we working hard to identify manatees in distress due to devastating seagrass losses in Indian River Lagoon.

This involves increased monitoring and a minimum of providing manatees with limited food and water when medically indicated while monitoring the manatees’ response and body condition. Experimental feeding efforts were undertaken this past winter by the Florida Fish and Wildlife Conservation Commission to supplement the diet of malnourished manatees seeking warm water refuge in the Indian River Lagoon. Ultimately, the decision of whether to feed manatees is physiologically and logistically complicated as it is currently illegal to feed or give water to manatees. Please leave it to the experts! Do not feed manatees on your own, and share this message with your friends, family, and neighbors. (Click here to watch a short video with more information about why you should not feed or give water to manatees.)

Save the Manatee Club and our partners are also working diligently on improving water quality to enable natural regrowth of seagrasses and to replant areas where replanting is feasible now.

  • See Save the Manatee Club’s Work in 2021-2022 below for more information on our activities to help manatees during the UME.

What You Can Do

Please get involved with local nonprofit groups and elected leaders in your area to help address these issues. Dirty water is a threat to health, to our economy, and to the quality of life for humans and other species like manatees.

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