Scott D. Wright, PhD
Florida Marine Research Institute, St. Petersburg, FL
Over the past 16 years there has been a careful documentation of the mortality of the West Indian Manatee (Trichechus manatus) throughout much of its range. The largest population of manatees exists along the coastal waters of Florida. There has been a continued spiraling increase in mortality initially the result of increased efficiency in carcass recovery but currently an accurate representation. At least a third of all mortality results from collisions with watercraft. Another significant category of mortality is the perinatal or dependent calf category and finally a large number of carcasses are too decomposed to make an accurate determination of cause. Undoubtedly there is an overlap of categories and the documentation effort is not absolute, so there is an unknown number of mortalities as well. The current manatee population estimate (December 1989) for Florida is 1250. Total mortality for 1988 was 133, for 1989 166, and 1990 over 200.