A few years back a study was made about harvesting their flesh to feed the homeless; it did not seem to go anywhere. They thrive in warm weather but during a deep freeze will fall out of palm trees just like coconuts. They eat plants and flowers and defecate a pound of crap a day just like a medium size dog. Some consider them pests and others think of them as pets. You can legally trap and capture them in your property and you can kill them as long as long as you do it without inflicting suffering or cruelty. Some complaints have been made by neighbors against neighbors but no indictments have resulted to date. In order to curtail their expansion legislation was passed making it illegal to release or relocate them so legally speaking if you trap and capture one your choices are to kill it swiftly or feed it until it dies of natural causes. You ask how to keep them off your boat's deck? Some say using the same ineffective methods utilized for birds, Shiny CD's, owl dolls, and scratchy noises. Unless you are a sure shot firing at them with a pellet gun (no fire arms as the water does not belong to you) could inflict suffering or put a nice dent on your deck.