Golfo Dulce: Osa Peninsula and Coronado Bay (Costa Rica)

Golfo Dulce: Osa Peninsula and Coronado Bay (Costa Rica)

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Golfo Dulce lies between the Osa Peninsula and the southern Pacific Coast of Costa Rica. Coronado Bay lies to the northwest. The peninsula contains a complex of national parks and protects one of Central America's most significant stands of the virgin rainforest.

Golfo Dulce

Golfo Dulce ("Sweet Gulf") is a gulf in Costa Rica in southern Puntarenas province. It takes its name from the large amount of freshwater that flows into it from four rivers whose mouths harbor large areas of protected mangroves.

The gulf lies between the Osa Peninsula and the southern end of the Pacific Coast of Costa Rica and measures about 15 mi (24 km) in breadth. Costa Rica's other gulf, the Gulf of Nicoya, lies on the northern section of its Pacific coast.

It is a region of high biodiversity. In the northeast part of the gulf is the Piedras Blancas National Park, with its 14,000 ha (34,595 acres) of protected rainforest. In 2018, the Government of Costa Rica assigned the wetlands north of Golfo Dulce as a sanctuary for the scalloped hammerhead shark, creating 4,000 ha (10,000 acres) of 'no-take' zone: the first shark sanctuary in Costa Rica.

The Golfo Dulce is considered a tropical fjord with an average annual temperature of 30 °C (86 °F), an extremely rare biome. The area has seventeen protected reserves which amount to 3% of Costa Rica's land area.

The area contains 50% of the flora and fauna of Costa Rica and receives 5 - 6 mm (200 - 236 in) of rain per year. The ecosystem has two parts: a marine ecosystem and a terrestrial ecosystem.

The marine ecosystem of the Golfo Dulce teams with life and includes marine mammals, reptiles, sharks and invertebrates. The Golfo Dulce has several species of whales that visit the area and use it as a breeding ground and nursery for their respective calves.

The area is an ideal breeding ground due to the warm water temperature, which averages 29.27 °C (84.7 °F), paired with an abundance of small fish and plankton that these species feed on. The species of whales that frequent this area include Humpback Whales, Spotted Dolphins, Bottlenose Dolphins, and Orcas.

Sea turtles are the most prominent marine reptiles living within the gulf, with several species, such as the Pacific Green Sea Turtle, Olive Ridley, Hawksbill and Pacific Leatherback. The sea turtles in the area are drawn by the warm water temperature and the presence of jellyfish and marine plants on which the sea turtles feed. Along with sea turtles, yellow-bellied sea snakes, saltwater caimans, and saltwater crocodiles also inhabit the area.

Several sharks live within the gulf, including the Whale Shark, Scalloped Hammerhead, and Rays. Along with sharks, other large fish, such as Needlefish, Dorados, and Marlins, live in the Gulf. While Needlefish are protected, Marlins and Dorados are popular targets for sport fishing. Numerous invertebrates live in the Golfo Dulce, which include jellyfish, Portuguese Man-O-Wars, sea stars, coral reefs, crabs, and sea mollusks.

The ecosystem surrounding the actual Golfo Dulce is just as rich in life as in the water, with 2 - 3% of flora found nowhere else on Earth. The ecosystem has numerous reptiles, birds, amphibians, insects and even mammals. The terrestrial reptiles in the Golfo Dulce include Iguanas, Saltwater Caimans, Saltwater Crocodiles, and numerous species of snakes, both venomous and non-venomous. There are also several species of geckos.

The primary species of birds in the area are the Scarlet Macaw and the Toucan. The amphibious species can be found primarily close to bodies of freshwater such as rivers and lakes. These include newts, toads, skinks, and even poison dart frogs.

The terrestrial mammals in the ecosystem are monkeys and horses, though the horses are domesticated and not native to Costa Rica. The species of monkeys include the Central American squirrel monkey, Geoffrey's spider monkey, the Mantled howler monkey, and the White-headed capuchin monkey.

Map of Costa Rica

Map of Costa Rica

Osa Peninsula

The Osa Peninsula is situated to the west and north of Golfo Dulce; it contains the largest land area of protected ecosystems within Golfo Dulce. Because of this, the area attracts numerous eco-tourists.

It is located in southwestern Costa Rica, in the Puntarenas Province, with the Pacific Ocean to the west, Golfo Dulce to the east and Coronado Bay to the northwest. The peninsula was formed geologically by a faulting system that extends north into California.

Costa Rica's second largest peninsula, Osa, measures about 30 km (20 mi) northeast-southwest and about 55 km (35 mi) northwest-southeast. The generally low-lying terrain is used for livestock raising. Costa Rica's Nicoya Peninsula lies on the northern section of the coast.

The peninsula contains a complex of national parks and refuges. Corcovado National Park is located on the southern part of the peninsula and is part of the Osa Conservation Area, which protects one of the most significant stands of virgin rainforest in Central America.

The peninsula is home to at least half of all species living in Costa Rica. The main town on the peninsula is Puerto Jimenez, which has its own airport and provides access to Corcovado National Park and the coastal villages of Cabo Matapalo and Carate.

Coronado Bay

Coronado Bay is a bay of the Pacific Ocean located on the southwestern Pacific coast of Costa Rica, which lies to the north of the Osa Peninsula. The bay measures approximately 40 km (25 mi) from northeast to southwest and extends from the town of Quepos southeastward for about 100 km (60 mi) to San Pedro on the Osa Peninsula.

A vast delta (Delta del Diquís, Delta Sierpe, or Delta Térraba) is located on Coronado Bay. It is the mouth of the Térraba (Diquis) River, which is Costa Rica's largest. Offshore are numerous islands.

Osa Peninsula in Costa Rica via NASA

Osa Peninsula and Golfo Dulce in Costa Rica via NASA