According to the Save the Manatee Club, West Indian manatees face a variety of threats, including algal blooms and seagrass loss, strikes from boats and watercraft, harassment and climate change.

“Over the years, researchers have attempted to identify and quantify West Indian manatee distribution, population size and causes of mortality in order to understand manatees and the threats to their survival,” the website said. “They have isolated several causes of manatee deaths, most of which are directly related to human contact or encroachment. If these sources of mortality are not controlled, manatees may become extinct.”

Artist Nancy Stahl of New York City created the graphic illustration of a manatee lolling close to the surface of the water that Postal Service art director Derry Noyes used to design the Save Manatees stamp.