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Mona Island, Puerto Rico

From the archives

By Harry Angus

Dazzling coral reefs, breathtaking cliffs and a multitude of caves make Mona Island the perfect habitat and the best kept Caribbean refuge to more than a hundred endangered species. Giant iguanas and sea turtles, red-footed boobies and many other migrating birds will be your welcoming hosts during a visit to this small island sandwiched between Puerto Rico and the Dominican Republic. Viewed from the air, this bean-shaped island looks like a giant piece of green puzzle placed over the dark blue ocean. Vertical cliffs rise from the ocean as giant walls surrounding its coasts. Mona’s uniqueness among other Caribbean islands lies in its use as a natural reserve for the conservation of sea turtles and the strict protection program implemented to preserve its ecosystem. The island is not inhabited except by the Puerto Rico Department of Natural Resources (DNR) personnel — resident biologist and rangers. Ecotravelers, nature lovers, biologists and ecologists are most welcomed.

Fauna and Flora

Because of its hot, dry climate and its limestone soil, Mona Island is a heaven for ecological conservation. The Mona Iguana, certified as threatened by the Endangered Species Act of 1973, is a four feet long reptile found only in the Mona Island. They dig their nests in the dry soil between the dense vegetation. Another family of the long Mona Iguana is the Geco Oriundo. Unlike its native cousin, this tiny iguana only reaches about an inch long. It is easily recognized by a dark spot over its neck and can be found in the flatter southern areas. Another interesting native is the Coqui de Mona, a close cousin of the famous tiny frog encountered only in Puerto Rico. They might be difficult to spot because of their size but the high pitch concert they hold at night is unmistakable.

The North side is the refuge to dozens of different species of migrating birds, the most common is the red-footed booby. The cliffs and the rocky soil are ideal for nests making Mona their favorite winter home. The waters surrounding the island are the most hospitable habitat in the Caribbean for over 270 species of fish and endangered sea turtles who have found the peace and tranquillity needed for their reproduction. The most famous ones are the Hawksbill and the Leatherback sea turtle.


Mona Island is 42 miles from the western coasts of Puerto Rico. The island is about seven miles long and four wide with an approximate area of 13,000 acres. Mona has more than twenty miles of coast, 90% consist of abrupt cliffs of over 200 feet high rising vertically from the ocean. The island reminds of Saba with the difference that Mona is practically flat top. The highest peak is about 300 feet above sea level. Because of its size and topography, Mona is dry as opposed to Puerto Rico. The island is classified as having a semi-arid, subtropical climate. Temperature is between 80 to 90 all year long. About 2% of Mona’s surface is formed by caverns, penetrating horizontally from 150 up to 800 feet inside the limestone soil.

The island is located close to the deepest ocean trench of the Atlantic Ocean: the Puerto Rico Trench. Between Mona and Puerto Rico, ocean depths reach over 3,000 feet. Ocean depths close to Mona’s cliffs are more than a hundred feet. Coral reefs surround the South coast where a myriad of keys protect more than five miles of white-sand beaches.

What to do

Mona offers over 13,000 acres of unspoiled ecological treasures. Camping is allowed only in the three beaches located on the South and South West of the island. Trails join the three beaches up to the eastern point of the island where the lighthouse is located. During the day, you can go hiking, bird watching, snorkeling or scuba. Activities can be coordinated with the resident biologist if you want to learn about the ecosystem of the island. It is required to visit the caverns with a guide.

Star gazing at night may be the most unforgettable experience of a trip to Mona. Because of the darkness, the sky offers at night myriad of bright stars, a spectacular experience for the amateur astronomer equipped with a telescope. A sunset viewed from Mona can also be a remarkable experience.

Mona is without any doubt the best snorkeling site of the Caribbean because of its crystal clear waters, allowing visibility as far as 150 feet under the sea. Playa Carmelita is the best snorkeling site. Coral reefs surround the South coast offering a palette of the brightest colors and the most complete reef styles such as the brain-type, the common sea fan, the finger coral, the fleshy and the stony corals. Colors vary from intense dark violet to yellowish mustard. Dolphins and humpback whales are also visible during the winter along the Mona shores.

The hunting season starts from the beginning of December to the end of April. During this period, hunters can visit the island Monday through Thursday while other visitors are accepted only on weekends. The Puerto Rico’s Department of Natural Resources — known by its Spanish acronym DNR — has implemented strict rules to allow hunting while continuing to protect the environment and the security of all visitors. For the complete regulations, visitors should contact the DNR.

Hunting is allowed to control the growing number of pigs and goats, two unwelcome species that are the worst enemies of the endangered iguanas and the sea turtles. Goats destroy Iguana’s nests and the pigs reach the sandy beaches to eat the turtle eggs. Controlling their population is a major concern for the protection of Mona’s ecosystem.


Mona island is under the protection of Puerto Rico’s Department of Natural Resources since 1975. It is recognized by Puerto Rico as a Natural Reserve and the DNR is doing a terrific job in protecting this fragile source of ecological treasures. A group of three to four rangers is always on the island along with a resident biologist. They are rotated on a weekly basis.

Rules are very strict to maintain Mona as the best ecological site of the Caribbean. No more than a hundred visitors can be on the island at any time. The nesting areas of the sea turtles are closed to the public at night. Visitors have to bring their own food, drinking water and all camping equipment. Open fires are not allowed. It is also the visitor’s responsibility to carry all solid waste back to Puerto Rico. Showers and bathrooms are available at Playa Sardinera, one of the three camping sites. Brochures provided by the DNR list the rules to follow during a trip to the Mona Island. Upon arrival, rangers offer an additional lecture to all visitors.

Travel Tips

The island can only be accessed from Puerto Rico. From the west coast towns of Mayaguez and Cabo Rojo, chartered boats are available for the six hour trip. Because of the distance and the wide range of activities available, it is recommended to make plans for at least a few days. The waters are rough in the Mona Passage, especially during the months of November to March. Fishermen offering the sea transportation schedule their trip at night when the ocean is calm. Small planes used to land on a small grass field in the South coast of Mona.

Ecotravel is still a very ambiguous term due to the diversity of sites and the wide range of activities classified as having an ecological value. In addition, this booming sector of tourism has a peculiar niche market sharing so many different needs that it has become almost impossible to clearly define ecotravel. However, there is no better place in the Caribbean where ecotravel finds its most basic and indisputable meaning than the Mona Island. It is one of the best ecological site of the Caribbean, a must-see for ecotravelers and scientists alike. Myrna Aponte, the supervisor in charge of the Conservation Division of the Department of Natural Resources could not find better words to describe Mona Island when she said ” Mona is the best kept natural reserve of the region; its ecological, cultural and historical values are unsurpassed and it is not an overstatement to name it the Galapagos of the Caribbean.”

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