Isla Caja de Muerto, island located off the southern coast of Puerto Rico

Isla Caja de Muerto, island located off the southern coast of Puerto Rico

The natural system, including Isla Caja de Muertos, Cayo Morrillito, Cayo Berbería and surrounding waters, make up the Isla Caja de Muertos Nature Reserve. It was designated as a reserve on January 2, 1980, by the Planning Board, following the recommendations of the Department of Natural and Environmental Resources, in order to protect this area of great natural value and ensure that the uses and activities do not affect their natural resources.

Location and Geographical Features
Isla Caja de Muertos is the main component of the nature reserve and is located in the Caribbean Sea, 4.8 nautical miles from the south coast of the municipality of Ponce, between latitudes 17°55” and 17°54″ north and longitude 66°33″ west. The island is approximately 2.75 km long and 1.85 km wide, with a total area of 400.36 acres. Cayo Morrillito is connected to Caja de Muertos by a bank of shallow waters about 5.49 meters deep. On the other hand, Cayo Berbería, which is a mangrove islet is located at a distance of 5.5 km from Caja de Muertos and is connected to it through a bank of shallow waters about 3 fathoms deep (18 feet).

Historical Background
The island has been called different names in time: Angulo, Abeirianas or Abeirianay, Abeianay, Bomba de Infierno, Antías, Isla del Tesoro and Caja de Muertos. Of these names, it was Caja de Muertos that prevailed. It was in the 18th century that French writer Jean Baptist Labat called it “Coffre A`morr” (meaning caja de muertos or coffin), because when you look at the island from certain points of southern Puerto Rico, it gives the impression that you are looking at a dead body on a plateau.

The island was a temporary hideout for patriots (Betánces and Ruiz Belvis) for meetings of the Masons. There is now a monument to Mason on the way to the lighthouse. It also served as an improvised hideout for pirates who kept their treasures there. On the other hand, the Indians left us petroglyphs in one of the caves and in the rock shelters. The place has served as a source of inspiration for some local writers such as Dr. Cayetano Coll y Toste who in 1928 wrote the legend El Tesoro del Pirata Almeida (Pirate Almeida`s Treasure), which mentions the island. In 1935, Vicent Starret mentioned in a British magazine the possibility that Caja de Muertos was the island that inspired Robert Louis Stevenson to write the famous novel Treasure Island. The island has a lighthouse, a historic monument built by the Spanish government in 1880, from where there is a panoramic view of the island and the southern coast of Puerto Rico.

Ecological Value
Bathed in the transparent waters of the Caribbean Sea and located in one of the driest and most arid areas of Puerto Rico, Isla Caja de Muertos Nature Reserve holds a variety of natural resources framed in a spectacular scene. On the island we can find mangroves, coral reefs, sandy beaches, rocky coasts, xerophytic forest (dry and thorny), caves and nesting areas for sea turtles (Hawksbill turtle) and seabirds.

Historic lighthouse at Caja de Muerto, built by the Spanish in 1880

Historic lighthouse at Caja de Muerto, built by the Spanish in 1880

Isla Caja de Muertos Nature Reserve serves as a place for nesting, feeding, and protection to a fauna that colonized and continues to colonize the island through natural migration and other species that were introduced on purpose by the previous owners of the island and other visitors. Because of the short distance between the island and southern Puerto Rico, the fauna is composed mostly of species originating on the big island. Among the species of resident and migratory sea birds, some of them endangered, we can mention the brown pelican, magnificient frigatebird, red-billed tropicbird, osprey, brown booby, several species of plovers, kingfishers, royal tern, sandwich tern, and least tern.

Other animals characteristic of Caja de Muertos are reptiles. There is a relative abundance of various species of lizards, iguanas (such as Ameiva exsul), the blue-tailed iguana (Ameiva wetmorei), and (Alsophis portoricensis) snakes. Hawksbill turtles (Eretmochelys imbricada) and green turtles (Chelonia mydas) —two species of endangered turtles— have been observed and nest on the beaches of the south of the island.

The area is visited by dolphins and manatees (aquatic mammals in danger of becoming extinct). This nature reserve has beautiful marine organisms such as sea urchins, starfish, sea cucumbers, conch, crab, chitons, and a variety of fish. There are also spiders, mites, and ants. The existence of the above-mentioned species requires protection of the area.

The flora found in the Caja de Muertos nature reserve is very similar to those in the Guánica Dry Forest. We see some thorny species such as cacti of great beauty and size that adorn the sidewalks through which visitors pass. The existing vegetation is deciduous and tends to densely cover the ground. In the nature reserve there is a wide variety of herbaceous plants, vines, climbing plants, trees, shrubs, and thorny groves. Among these, four rare and endangered species have been identified. These include the prickly pear (Harrisia portoricensis), which was introduced by the Natural Reserve Department.

In this nature reserve we can observe the presence of toxic plant species such as (Ehretia tinifolia) (which has an itching effect on people’s skin) and Hippomanel mancinella (manzanillo or little apple) whose fruit can cause poisoning or gastric ulcers in those who ingest it. The island has a mangrove basin in which the dominant species include white mangrove and button mangrove. These are short and very dense. On the other hand, the mangrove that forms the islet of Cayo Berbería, aside from providing habitat for various seabirds, also serves as a nursery for fish and protects many of the fish in the reef and other marine life. Marine vegetation consists mainly of algae and Thalassia meadows. They cover a vast submarine area and serve as habitat and food for manatees, hawksbill turtles, and other marine organisms that come to the place.

Coral Reefs
The nature reserve has a coral reef system of colorful and extraordinary beauty. Its largest development is located to the northeast of the island, forming a lagoon reef. Corals serve as a breeding ground for a variety of submarine animal species and protect the coasts by reducing the speed of water.

Public Responsabilities
Learning to understand and appreciate Isla Caja de Muertos Nature Reserve is everyone’s responsibility. The Reserve offers opportunities for studies, photography, bird watching (attractive for environmental tourists and for nature lovers who come from abroad), hiking, sea bathing, diving, among other activities. Isla Caja de Muertos Nature Reserve is handled by the Division of Reserves and Refuges of DNER and managed in conjunction with the Autonomous Municipality of Ponce. Visit, protect, and preserve it for the enjoyment of present and future generations.


Author: Grupo Editorial EPRL
Published: August 27, 2014.

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