Manatees, often called “sea cows,” are found in the waters surrounding Puerto Rico. They represent a distinct population of the West Indian manatee. While their federal classification has changed, these animals face challenges, making their conservation a priority.
Manatees in Puerto Rico
The Antillean manatee (Trichechus manatus manatus) is the specific subspecies found in Puerto Rico’s coastal areas. This subspecies is genetically distinct from the Florida manatee. Antillean manatees prefer warm, shallow coastal waters, estuaries, lagoons, and mangrove areas, which provide abundant food sources and shelter.
Manatees are herbivores, primarily eating seagrasses like turtle grass (Thalassia testudinum), shoal grass (Halodule wrightii), and manatee grass (Syringodium filiforme). They also consume algae and the leaves and roots of mangroves. Manatees graze for several hours daily, consuming a significant portion of their body weight in aquatic vegetation.
Manatees are typically solitary, but they may gather in groups in warm water refugia or during breeding periods. Their reproductive rate is low, with females typically giving birth to a single calf every one to three years. Aerial surveys between 2010 and 2014 estimated the population at 312 to 535 individuals, though some sources indicate fewer than 600-700 remain.
Higher concentrations of manatees are observed in specific areas across the island. These include Jobos Bay National Estuarine Research Reserve on the southeast coast, known for its significant Antillean manatee population. Other important habitats include La Parguera in the southwest, Ceiba on the east coast, and the areas around Guayanilla, Guánica Bay, Cabo Rojo, and Mayagüez.
Protecting Puerto Rico’s Manatees
The Antillean manatee in Puerto Rico is protected under U.S. federal and local laws. Though reclassified from “Endangered” to “Threatened” under the U.S. Endangered Species Act (ESA) in 2017, the West Indian manatee (including the Antillean subspecies) remains protected by the ESA and the Marine Mammal Protection Act. Locally, it was declared Puerto Rico’s official mammal in 2013.
Despite these protections, manatees in Puerto Rico face several threats. Collisions with watercraft (boats and jet skis) are a leading cause of human-related mortalities. Habitat loss and degradation from coastal development, pollution, and harmful algal blooms that reduce seagrass beds also pose risks to their survival. Entanglement in fishing gear and diseases like toxoplasmosis (linked to cat overpopulation) further contribute to mortality rates.
Ongoing conservation initiatives address these threats and support manatee recovery. The Manatee Conservation Center (Centro de Conservación de Manatíes de Puerto Rico) in Bayamón plays a central role. This center conducts rescue and rehabilitation for injured or orphaned manatees, provides veterinary care, and engages in population research and community outreach.
Public awareness campaigns are also important for conservation. Puerto Rico observes “Manatee Protection Awareness Day” on November 4th to educate citizens. Measures like speed limit buoys in manatee zones encourage responsible boating behavior. Protecting habitats, such as Jobos Bay National Estuarine Research Reserve, helps ensure suitable environments for manatees.
The public can contribute to manatee protection by reporting sick, injured, dead, or tagged manatees to authorities like the Department of Natural and Environmental Resources (DRNA) Law Enforcement or the Marine Mammal Rescue Program. Boaters should adhere to speed limits in designated manatee zones, use polarized sunglasses to spot manatees, and operate watercraft responsibly to avoid collisions. Supporting manatee conservation centers through visits or donations also aids their work.