Sensing danger, the manatee will attempt to get away, but often there is not time to get out of the path of a speeding boat. And frequently there isn't sufficient depth to dive deeper. In the case of large power vessels and barges moving through shallow waters, the manatee may be caught between the vessel and the water bottom and crushed. Oil exploration and possible oil spills are threats to all marine and estuarine habitats. Crab trap lines and hoop nets used by commercial fishermen can also cause problems for manatees.
Harassment can also lead to separation of mother and calf.
Accounts of vandalism and even poaching have been reported in Florida and resulted in several manatee deaths. Flood Control Structures Manatees can be crushed in the closing of flood gates and canal locks that are used to control water levels throughout Florida. This problem is particularly acute in South Florida. Deaths due to drowning have also occurred when the tremendous suction created by the water rushing through the opening gates pins the animals under the water. In recent years, the South Florida Water Management District and the US Army Corps of Engineers have been working to monitor the opening and closing of these structures to help prevent this type of death from occurring.