Unlike many islands in the Caribbean, Puerto Rico’s underwater coral reef systems are still mostly healthy and intact. And where there’s a healthy reef system, there is an abundance of marine life.

Among Puerto Rico’s endangered marine creatures is the manatee, a 1,000-pound submarine-shaped mammal with a tail, two small flippers, and a wrinkled, whiskered face. The slow-moving herbivore lives in shallow, still waters, such as lagoons and bays. Their only natural predator is man, and because they often float near the water’s surface, they are particularly susceptible to collision with watercraft. The U.S. Fish and Wildlife Service operates a recovery program for the manatee, and if you spot one, you’re likely to see its tracking device, which looks like a walkie-talkie attached to its back.

Also endangered are the hawksbill and leatherback sea turtles, the latter of which is the world’s largest species of sea turtle, weighing between 500 and 1,600 pounds. There are several important turtle nesting sites in Puerto Rico, along the north shore and on the islands of Mona and Culebra. The turtles nest between April and June by climbing up on the beach at night and burying their eggs in the sand before returning to the sea. Unfortunately, turtle nests are vulnerable to animals and poachers, who prize the eggs. Several government agencies are involved in protected the nesting sites. If visitors want to help out, they should contact the Puerto Rico Department of Natural and Environmental Resources (787/556-6234 or 877/77-CORAL—877/772-6725, fax 530/618- 4605, info [at] coralations [dot] org, www.coralations.org/turtles), which accepts volunteers to catalog the turtles during nesting season.

Besides its endangered species, Puerto Rico has countless other varieties of thriving marine life from rays and nurse sharks to puffer fish and parrot fish. The reefs themselves are sights to behold, with their brain coral, sea fans, and yellow cup coral, which blooms at night.

And although typically associated with colder waters, migrating humpback whales can be spotted along the island’s west coast between January and March.