Open-File Report 2015–1083
The endangered West Indian manatee (Trichechus manatus), especially the Florida subspecies (T. m. latirostris), has been the focus of conservation efforts and extensive research since its listing under the Endangered Species Act. On the basis of the best information available as of December 2012, the threats facing the Florida manatee were determined to be less severe than previously thought, either because the conservation efforts have been successful, or because our knowledge of the demographic effects of those threats is increased, or both. Using the manatee Core Biological Model, we estimated the probability of the Florida manatee population on either the Atlantic or Gulf coast falling below 500 adults in the next 150 years to be 0.92 percent. The primary threats remain watercraft-related mortality and long-term loss of warm-water habitat. Since 2009, however, there have been a number of unusual events that have not yet been incorporated into this analysis, including several severely cold winters, a severe red-tide die off, and substantial loss of seagrass habitat in Brevard County, Fla. Further, the version of the Core Biological Model used in 2012 makes a number of assumptions that are under investigation. A revision of the Core Biological Model and an update of this quantitative threats analysis are underway as of 2015.
First posted May 20, 2015
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Runge, M.C., Langtimm, C.A., Martin, Julien, and Fonnesbeck, C.J., 2015, Status and threats analysis for the Florida manatee (Trichechus manatus latirostris), 2012: U.S. Geological Survey Open-File Report 2015-1083, 23 p., at https://dx.doi.org/10.3133/ofr20151083.
ISSN 2331-1258 (online)