Funded by: U.S. Fish & Wildlife Service

Current manatee population modeling indicates that the sub-population of manatees in Southwest Florida may be in decline. More data is needed for a better understanding of this sub-population and for the Everglades region in particular. It is known through aerial surveys that substantial numbers of manatees winter at three main sites in the Everglades during the coldest periods of the year: the Port of the Islands canals, a pond across from Wooten's Wildlife Park (Wooten's), and in canals at Big Cypress National Park staff headquarters. All of these aggregations are known as secondary warm water sites, which are thermal basins that temporarily retain water that is warmer than ambient temperatures, but that are subject to cooling in especially cold winters. Baseline data are needed to document the survival of individuals using these sites from year to year, so that managers can understand the long-term survival of these animals, to learn what percentage of them use warm water sources other than the Everglades, and for those that do not migrate elsewhere, to potentially see the effects of using only secondary warm water sources during cold periods.

Staff use digital photography to document individually scarred/marked manatees for comparison to previous images in the existing statewide photo ID database. During winter surveys staff also create scar drawings of sighted manatees and collect environmental data (water and air temperature, wind speed and direction, etc.). This study will provide managers with a larger dataset of individuals wintering in secondary warm water sources in the southernmost part of the state, as well as an understanding of site fidelity of these animals. The data and expertise obtained through this study can be compared with data for manatees currently dependent upon artificial warm water sources which will be critical in the future as existing power plants shut down.