In Springtime, Manatee's Thoughts Turn to Grassbeds
As the weather warms in Spring, scientists tend to see more manatee movement. Cape Romano (~ 25.857N, 81.669W) and other TTI "outer island" areas of their habitat are used by the manatees much more often in spring. And the manatees remain there for longer than they do in winter.
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| Three Manatees Feeding on Seagrass Credit: USGS-Sirenia |
The
Mother of All Grassbeds
Why
do you think the manatees go out to these "offshore" areas in
the first place? The answer is that seagrass beds are abundant here, and
they are an essential part of the manatee's diet and their habitat. Sirenia
Project biologist Susan Butler explains that:
"Off of Cape Romano the grassbeds are extensive and are well documented as sites for manatee feeding. Jim Reid has often referred to these beds as 'the mother of all grassbeds'. There are many grassbeds around the outer islands of the Ten Thousand Islands area too, and these are also frequently used, however they are not nearly as extensive as the Cape Romano grassbeds."
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Why do the manatees move to the outer areas in Spring but not much in winter? Susan Butler reports that during the colder winter months, it is believed that more of the manatees are staying close to their warm water sites (i.e. POI) and choosing not to expend the energy needed to go further out to Cape Romano to feed. "We notice that during the coldest fronts when the animals do go out to feed, they seem to go to the nearest grassbeds and then come back in. Perhaps this is a choice so as not to get 'stuck' out in the cold."
After the warm spring weather comes, Susan notes that "the manatee's emphasis on finding and staying in one of the known warm water areas will fade." By springtime, almost all of the water is warm, so the manatees can migrate more freely away from warm water areas.
Try This! Journaling Question
The seagrass beds are important parts of the manatees' habitat because they are a feeding area. How do you think the manatee would be affected if the seagrass beds were destroyed or damaged?
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| Aerial Photo of Seagrass Beds Notice the scaring damage to these beds, caused by boats. Credit: USGS-Sirenia |
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