Funny story...I lived in Cocoa Beach,FL and loved to go to the Indian River to take sunset pictures. I waded into the river waist deep to get away from the shorea edge. While composing my picture I didn't see a manatee swim up to me. I guess I wasn't giving him/her the attention they wanted and he grab my leg with his flipper. Let me tell you Jesus is not the only one who can walk on water, I did that evening.
The manatee just looked at me standing on shore with the where did you go look. The are awesome creatures. Very loving and gentle. Just remember they are endangered and really should not be bothered in the wild.
Enjoy your trip you'll love the springs and seeing the manatees.