As I am sure you know Mike, you will never catch any fish with manatee chum.
It seems like every time a manatee would approach the boat*, the fishing goes to hell........might as well toss your rod in the water and head home.
Even fish hate manatees.
* YES.....can you believe it???? I have actually SEEN these rare and elusive creatures. According to one study, I saw the entire Florida population of manatees in one day of fishing.