Osa Conservation Area
The Osa Conservation Area (ACOSA) in Costa Rica?s South Pacific, contains important marine and coastal ecosystems in a very good state of conservation. Of note are the Ballena Marine National Park, the Térraba-Sierpe National Wetland, the Biological Reserve Isla del Caño, Corcovado National Park and the tropical fjord of Golfo Dulce. The region has a 245 km. long coastal strip that stretches from the mouth of the river Barú to Punta Burica.
In the coastline estuaries and deltas are large mangrove swamps with a high level of structural development and biodiversity. One are worth highlighting is the Térraba-Sierpe National Wetland for its size, structural complexity and biodiversity. Extending over 16,700 hectares, these wetlands represent 43% of the mangrove swamps of Costa Rica.
The largest coral reef area in Costa Rica is located in the ACOSA area particularly in the Ballena Marine National Park (BMNP), the Biological Reserve Isla del Caño (BRIC) and Golfo Dulce (GD). There are isolated corals in Corcovado National Park in locations like Salsipuedes, Punta Llorona and San Pedrillo. These coral reefs are important for their great diversity in fish, molluscs and crustaceans. The BMNP was the first marine park created in Central America. The Golfo Dulce fjord, with its anoxic seabed, is a unique ecosystem in the region. Together with the Gulf of Cariaco in Venezuela, Darwin Bay in Galapagos and Kaoe Bay in Indonesia, Golfo Dulce is one of the four tropical fjords in the world.
Seventeen species of zooxanthela corals and thirteen of smooth corals are reported to exist in the area. The highest diversity of corals is found in the BRIC with 15 species and in the BMNP with 134. 333 species of fishes have been reported to date, yet only eight species of sharks, which shows the low number of studies carried out in the area. This is also the case with the molluscs (318 species) and crustaceans (152 species). There are 33 species of equinoderms and 14 of marine mammals.
