Manatees are present in the coastal and estuarine waters of Puerto Rico, representing a distinct population of marine mammals in the Caribbean. The island is home to the Antillean subspecies of the West Indian Manatee, which utilizes the shallow, protected waters around the archipelago. They were declared the island’s official marine mammal in 2013. This population faces human-related pressures that necessitate focused conservation efforts for their long-term survival.
The Specific Manatee Species in Puerto Rican Waters
The manatees inhabiting the waters surrounding Puerto Rico are the Antillean manatee (Trichechus manatus manatus). This is one of two recognized subspecies of the West Indian Manatee, distinguished from its Florida counterpart by cranial characteristics and genetic markers. Antillean manatees are large, gray-brown aquatic mammals, reaching 10 to 12 feet in length and weighing between 800 and 1,200 pounds as adults.
These herbivores primarily forage on submerged aquatic vegetation, such as seagrasses and freshwater plants. They may consume up to 10% of their body weight daily, using their flexible, whiskered upper lip to grasp vegetation. Manatees are slow-moving, typically cruising at three to five miles per hour, making them dependent on shallow, protected waters for feeding and resting. They must surface regularly to breathe, usually every three to five minutes, though they can remain submerged for up to 20 minutes when resting.
Coastal Habitats and Distribution Hotspots
Manatees in Puerto Rico favor habitats that offer warm, shallow water, abundant submerged aquatic vegetation, and access to fresh water sources. They are often found in coastal lagoons, estuaries, and protected mangrove channels where wave action is minimal and food is plentiful. This preference for a mix of marine and freshwater environments dictates their distribution around the island.
Several specific locations are recognized as high-concentration areas, or “hotspots,” where manatee sightings are most frequent and consistent. These include the coastal areas near Ceiba on the eastern side of the island and the Jobos Bay area, spanning between the municipalities of Guayama and Salinas on the southeast coast. Manatees also concentrate along the southwestern coast, particularly around Guayanilla and Guánica Bay, as well as the mouth of the Guanajibo River near Cabo Rojo and Mayagüez.
Conservation Status and Major Local Threats
The Antillean manatee population in Puerto Rico is considered a distinct and vulnerable group, estimated at only 312 to 535 individuals. While the West Indian Manatee species is classified as “Threatened” under the U.S. Endangered Species Act, the local population is considered “Endangered” by the Puerto Rico Department of Natural and Environmental Resources. This small population size and naturally low reproductive rate make the manatees highly susceptible to external pressures.
The most significant human-related threat is collision with watercraft, including speeding boats and jet skis. Since manatees are slow-moving and must surface in shallow, busy coastal areas, they are frequently struck. Trauma from these strikes is the leading cause of direct human-related mortality. Habitat degradation is another major challenge, driven by coastal development, pollution runoff, and the loss of seagrass beds, their primary food source. Emerging diseases, such as toxoplasmosis, are also a growing concern, indicating the negative impact of declining environmental health.
Efforts to Protect the Manatee Population
Efforts to ensure the survival of the Antillean manatee population are spearheaded by the Caribbean Manatee Conservation Center (CMCC). This facility operates as a care center, providing rescue, rehabilitation, and veterinary care for injured or orphaned manatees. The center’s work includes extensive population research, such as aerial surveys and genetic studies, to understand distribution and health.
Conservation strategies emphasize public outreach and education regarding responsible marine behavior. Boaters are encouraged to use polarized sunglasses to spot manatees and observe posted slow-speed zones in known habitats. Citizens are encouraged to report sightings of sick or injured animals to the CMCC, aiding the monitoring and recovery process.