Ballena National Marine Park was created in 1990, to protect the coral and rock reefs in Coronado Bay, south of Costa Rica. The park extends over 13 kilometres of sandy shores and rocky coasts, and includes the Uvita tombolo, several beaches (Bahía Pedegrosa, Ballena, de Arco and Piñuela) and 4,500 hectares of sea around Ballena Island (2,5 hectares) and Las Tres Hermanas rocks. The park has a great wealth of scenic beauty, such as the beaches of grey sand at Ballena and Bahía fringed with lush vegetation, mainly coconut trees, beach almonds, mahoes and poros. Rivers and streams flow down from the steep hills and mountains of the interior, carrying water even during the dry season from December to April.
Other atractive sites are the Uvita tombolo, which is a rocky platform that juts out into the sea and is exposed at low tide, and the rivulets that are formed in the cliffs. The mainland scenery is complemented by the underwater world of coral reefs and by the islands, which are important roosting sites for seabirds.
Sedimentation caused by wave refraction has joined Uvita Island to the mainland, forming a tombolo 5 meters wide where it is easy to walk at low tide. At the tip of the tombolo there are sponges, sea anemones, corals, mollusks, crabs and echinoderms.
The islets of Ballena and Las Tres Hermanas emerge from the waters of the bay as part of a submerged arch that extends from Uvita Point to Piñuela Point. Ballena Island a is rocky promontory with steep slopes and sparse vegetation, surroundet by platforms that are exposed at low tide. In this remote area there are numerous green iguanas and cherepos. These two reptiles live on algae that grows in the saltwater pools and have very different behaviour from mainland members of the same species, which rarely approach the shore except when they are laying their eggs. The island is a refuge and roosting site for maginficent frigatebirds, whose only currently known nesting sites are Bolaños Islands near the border with Nicaragua and Guayabo Island in the middle of Nicoya Gulf. The rocky platforms that surround the island are the habitat of algae, sponges, echinoderms and other creatures adapted to the pounding surf.
The coral reefs are very altered by the deposits of sediments from rivers, the fishing activities of the shrimp boats which ply the waters of the bay, and the removal of tons of earth to build the Costanera Sur Highway.
The rock reefs are ideal mating sites for lobsters, giant conch, and several species of fish of economic value to the inhabitants of the neighboring villages who practice non-commercial fishing.
The bays of Ballena National Marine Park teem with anchovies, marine catfish, catfish, flying fish snappers, Caribbean snook, jewfish, common dolphines and bottle-nosed dolphins. This sector of the Pacific might also be the southernmost mating site of the humpback whale, a mammal that measures 15-16-metres long. It mates near the peninsula of Baja California in North America, and migrates to tropical and subtropical waters during the winter season.The humpback whale is an edangered species ot which there are only 5'000 left in the whole world.
The coastline habitat of beaches, mangrove swamps, estuaries, rivers and ravines attracts resident and migratory birds, such as the Northern boat-billed heron, littel blue heron, white ibis, black-collared hawk, greater yellowlegs, spotted sandpiper, black-bellied plover, whimbrel, turkey vulture, and king vulture.
The sandy beaches are are visited by olive ridley and hawkbill turtles from May to November, but mainly in September and October, when they arrive in huge numbers to nest.