The way manatees eat give some clues to the reasons why they are often referred to as “sea cows”. The large herbivores (aka plant-eaters) graze the sea for a large portion of their lives, usually consuming well over 100 pounds of food every day. Their diet consists of a wide variety of saltwater and freshwater aquatic grasses and plants, largely dependent on what’s available to them wherever they are at any given time. They will even resort to eating small fish if nothing else is available.
In fact, research has shown that manatee snouts are slightly adapted for their particular natural environment. They have highly complex mouths that, along with their front slippers, allow them to dig for and process the large amounts of food they require from a wide variety of sources. Their “marching molars” are consistently discarded and regenerated throughout their lives, a useful adaptation to the rough vegetarian diet they consume.
Because they are such un-picky eaters, local authorities and organizations need to keep a close eye on Crystal River and King’s Bay to keep manatees out of danger. For instance, plants that could be deadly to manatees in the area need to be monitored, and removed if necessary, to protect “sea cows” from their own insatiable hunger.
Unfortunately, this is not where the trouble ends with manatee vegetation. While some natural factors come into play, like changes in water salinity, many of the problems facing the health of vegetation in bodies of water like Crystal River are caused or exacerbated by humans.
One major threat to Crystal River vegetation is eutrophication and higher nitrate levels in the water due to sediment, nutrients, and chemicals introduced by storm-water runoff. These substances change the balance of the ecosystem, leading to an uncontrollable spurt of algae production. More algae may not sound so bad at first, but it can suck up a great deal of oxygen and block light to other plants that need it, killing off many sources of manatee food.
Boats can also be a damaging factor when irresponsible drivers steer boat propellers through seagrass beds, leaving a scar that could take years to heal—sometimes too long for the local manatee population.
There is a great deal of work being done, including extensive vegetation studies by biologists like Bob Bonde, to monitor and protect the sensitive habit of the Florida manatee. We here at Sunshine River Tours love giving our guests the opportunity to swim with manatees, but it’s even more important to us that they stick around for many years to come.