Nevertheless, they were endangered by human activity, mainly habitat loss and injury by ships and boats that used to run over them. The U.S. species, technically known as the West Indian manatee, dropped to under 1,300 in 1972 and were listed as "Endangered." It took a long time, a great deal of professional and volunteer human help, and laws about everything from pollution to "go slow" boating zones, but the big lugs have improved significantly. There are well over 6,000 animals today, and the government has recommended that they can be downgraded to "Threatened." If the action is completed, it will still be illegal to kill them, but some regulations may be removed. There are some environmental organizations who think the downgrade is premature, and there's a comment period and many other activities and processes ahead before action is taken.
The sirenians in general have had a hard time with humans. Dugongs are threatened or endangered throughout their tropical ranges, and the most spectacular, Steller's sea cow, lasted only a few decades between discovery and extinction. All the more reason to praise a success story.