Image by Chokniti Khongchu
Remember this: A manatee can be two things at once. It can hold an ecosystem together and reflect environmental health through its sensitivity to change.
As we forge ahead with the intrepid manatee, we learn that it is a keystone species and an indicator species. Like everything else, it must live and it must eat.
For your education going into this, a keystone species is an organism that has an essential impact on its ecosystem relative to its small population size, while the indicator species is an organism whose health or presence reflects the overall condition and quality of an environment.
The manatee's aura is very interesting. For interest sake, because I was chewing the fat on the eelgrass, what other things does the manatee eat, or has its eating habits changed due to the changing world that some politicians are in denial of while calling scientists fake and liars.
Let us look at some research. Our topic has been eelgrass or seagrass and manatee habitat-diet. I was reading an article titled, "Nutritional composition of forage resources consumed by Florida manatees (Trichechus manatus latirostris) vulnerable to seagrass decline in the Indian River Lagoon" printed in Aquatic botany, May 2026.
The dominate food source for a manatee is seagrasses but they are known to consume sixty species of aquatic macrophytes. Macrophytes are large aquatic plants visible to the naked eye that grow in or near water. There are three kinds:
Emergent: Cattails
Submerged: Eelgrass
Floating: water lilies and duckweed
Harmful algal blooms have caused seagrasses to decline. These are some of the algal blooms that threaten Florida Eelgrass:
1. Brown Tide (Aureoumbra Iagunensis)-Indian River Lagoon
2. Picocyanobacteria (Synechococcus spp)-Florida Bay
3. Blue-green algae (Cyanobacteria)-Creates low-oxygen dead zones
4. Nuisance Macroalgae and Phytoplankton aka Super Blooms-Starve vegetation of photons
In this one specific location of the Indian River Lagoon (IRL), studies suggested the manatees populating this area had a dietary shift from seagrass to macroalgae over the past fifty years.
Would this cause an evolution to the manatee? Darwinism? Or was it there all along as the backup plan?
The concern at this intersection is the consequence of this shift in food selection. This will express itself in nutritional and energetic means that suggestibly will have a variation of data difference based on different time frames for food source availability.
This study compared macronutrients of Carbon, Nitrogen and phosphorus and proximate composition (acid detergent fiber [ADF], ash, crude fat, crude protein, total digestible nutrients [TDN], and total nonstructural CHO [TNC] ) to ten known forage items consumed by manatees in the IRL.
The aim was to quantify macronutrient and elemental stoichiometry (C:N:P) of items consumed by manatees, evaluate the proximate composition of forage resources, and investigate the seasonal (wet vs dry) variations in macronutrient and proximate compositions.
The results from the abstract stated, "a macroalgae-rich diet provides readily digestible energy but contains significantly less fiber, and exhibits altered nutritional balances compared to seagrass. Such a dietary transition may compromise hindgut fermentation efficiency, disrupt symbiotic microbiota, and exacerbate malnutrition risks to manatees in Florida." (Allen et al., May 2026,
Pretty much, manatees need the grasses in their diet. Its one thing to do a short-term run on the switching of food based on availability but ideally you want them on the grasses.
When you consider the diet of a manatee, you get informed on the anatomy of this creature. The manatee's large intestine and cecum form a fermentation vat measuring 20-30 meters long, making up to 70% of their total gut mass. Just wow.
Digestion takes up to 4 to 10 days to pass through their gut allowing microbes time to break down tough plant cellulose. Genetic sequencing has identified 2,000 operational taxonomic units of bacteria in manatee faeces that is responsible for cellulose breakdown from low-nutrient seagrasses and abrasive aquatic plants.
When devising a plan to improve the diet of a manatee, you have to keep in mind that it is like gardening. You have to have good soil and nutrients to gain a payout of a harvest that is high quality and boost availability.
Scientific studies point out overwintering in Florida indicate seasonal temperature drops and dietary shifts, or fasting alter their gut flora and elevate stress indicators like fecal cortisol metabolites. This is in the arena of Cold Stress Syndrome.
Just because I want you to learn this term, in vitro, it is Latin for "in glass". It describes biological or medical experiments, tests, and procedures conducted outside a living organism in a controlled artificial environment such as a test tube or a petri dish. You are welcome.
Image by Qbert Studio
Did you know manatees are called Sirenians?
Manatees can eat 4-9 % of their body weight of aquatic vegetation each day. Because of foraging and diet, manatees can influence plant biomass, productivity, and community composition, while indirectly influencing invertebrate community and nutrient dynamics, including carbon sequestration.
Manatees possess extensive digestive systems that efficiently digest plant material such as cellulose via hindgut fermentation and absorb water from the plants they consume. Manatees consume foods high in fiber but low in protein and caloric value. They maximize extraction of nutrient through a slow gut passage time and demonstrate high digestive efficiency compared to other mammalian herbivores.
This is where the science paper reiterates the increasing anthropogenic impact due to changing environmental conditions since 2013, manatees along the Atlantic coast of Florida have experienced two consecutive unusual mortality events.
Between December 2020 and April 2022, a total of 1392 cases were documented that included 1255 manatee mortalities and 137 field interventions to assist live individuals exhibiting signs of starvation. The necropsies showed signs of malnutrition. The prevalence of emaciated manatees were high in the IRL where a regime shift from seagrass to phytoplankton based primary production has occurred since 2011 following a major decline in seagrass areal cover in the estuary.
A study investigating the UME (unusual mortality events) that occurred between 2012-2019 linked mortalities to clostridiosis (toxic effects of bacteria clostridium spp) and hypothesized that a diet low in fiber may have cause GI lesions providing a route for clostridial infection.
Image by K Fuadi
This reenforces the reasoning that federal and state agencies along with help from the public to set up manatee report and rescue routes, restoration of aquatic habitat for long and short-term habitat, and ensuring these endeavors have a clear plan on monitoring the efforts to rehabilitate the manatee in its environments.
What we have left after humanity has decided to re-imagine a location that is on an ecosystem or habits is our responsibility to protect. We must do everything humanly possible to make sure that it does not go asunder. It depends on the good human and what exactly that re-imagining is for, and in what way it can benefit the stewardship of the creatures of the Earth.
~Courtesy of the AOFH~
Interesting things to read:
"The In vitro Effects of Simulated Cold Stress Syndrome on the Gut Microflora of the Florida Manatee, Trichechus manatus latirostris".
Sources citated:
Allen, A.C., Sattleberger, D.C., Campbell, J.E., Kiszka, J.J. (2026, May) "Nutritional composition of forage resources consumed by Florida manatees (Trichechus manatus latirostris)". Aquatic Botany, Article 103972, Vol 204. https://www.sciencedirect.com/science/article/abs/pii/S030437702500107X#section-snippets