|One of the most endangered marine mammals in the coastal areas of the United States is the Florida manatee (Trichechus manatus latirostris). The Florida manatee population has been increasing and decreasing since 1991 along the east and west coast of Florida, respectively, and has a present population of about 6,250. However, the populations have been dramatically fluctuating due to various anthropogenic factors. The major causes of manatee deaths can be broken down into five categories: watercrafts, crushed/drowning by flood gate or canal lock, entanglement, perinatal, and other natural factors (such as disease and natural catastrophe). Unfortunately, three among these five categories are associated with human. Hence, I aim to estimate and compare anthropogenic and natural catastrophic effects on the manatee population dynamics. I will conduct a literature review to obtain the basic demographic data and develop a stage-structure population dynamics model of the Florida manatee. I will use the data from the Florida Fish and Wildlife Conservation Commission synoptic surveys to calculate average mortality rates and a 95% confidence interval of those four scenarios including baseline, anthropogenic threats, cold stress, and perinatal effects. I will simulate each scenario with the worst, average, and better cases from each of their average mortality rates for the next decade.