Bioko

Geography

Bioko lies in the Bight of Biafra on the Gulf of Guinea, about 32 kilometres (20 mi) off Cameroon and roughly 160 kilometres (99 mi) northwest of mainland Equatorial Guinea (Río Muni). The island's area is 2,017 square kilometres (779 sq mi); it is volcanic and mountainous, rising to Pico Basilé (3,011 metres (9,879 ft)).

Bioko has a total area of 2,017 km² (779 sq mi). It is 70 km (43 mi) long from NNE to SSW and about 32 km (20 mi) across. The island is mostly covered by tropical rainforest. It is volcanic and very mountainous, with the highest peak, Pico Basilé, at an elevation of 3,012 m (9,882 ft). It thus resembles neighbouring islands São Tomé and Príncipe. Like them, it lies on the Cameroon line. Its southernmost point is called Punta Santiago.

Bioko lies on the African continental shelf, separated from the African mainland by 32 km (20 mi) of water with a depth of only 60 metres. During the Pleistocene epoch, Bioko was connected to the African mainland. Bioko separated from Africa around 10,000 years ago, at the end of the Last Glacial Period.

The fire skink, a species of lizard found on the island, carries the scientific name of Mochlus fernandi, derived from Fernando Pó, the former name of the island.

Geology

The island is composed mostly of basalt, mostly alkali basalt and hawaiites, and to a lesser extent mugearites.

Climate

The island shows a strong north-south rainfall gradient driven by relief and the West African monsoon. Mean annual rainfall is ~1,930 millimetres (76 in) at Malabo (north) and ~10,920 millimetres (430 in) at Ureka in the south, among the highest recorded values in Africa. The principal wet season is April-October, with a drier season roughly November-March.

Protected areas and ecology

Two protected areas cover ~40% of the island: Pico Basilé National Park (est. 2000; ~32,256 ha) in the north, and the Luba Crater Scientific Reserve (~51,000 ha) in the south, a Key Biodiversity Area and AZE site centred on Mount Luba and the Gran Caldera.

Bioko forms part of the Cameroon line and hosts lowland Cross–Sanaga–Bioko coastal forests and Mount Cameroon and Bioko montane forests at elevation.

The endemic Pennant's red colobus Piliocolobus pennantii (CR) now persists primarily in southwest Bioko, and the drill Mandrillus leucophaeus (incl. the Bioko drill M. l. poensis) is globally Endangered. Long-term monitoring indicates that illegal bushmeat hunting is the principal threat to Bioko's primates, with tens of thousands of carcasses recorded in Malabo's market over multi-year surveys despite environmental legislation.

Demographics

The island has a population of 335,048 (2015 Census), divided into 2 provinces and 4 districts – Malabo (271,008), Baney (29,366), Luba (26,331), and Riaba (8,343). Its historic indigenous people are the Bubi people, who currently constitute 58% of the population. Other ethnicities include the Fang at 16%, Fernandinos at 12%, and the Igbo at 7%, as well as African and European immigrants.

Languages

Spanish has been an official language since 1844, when Spain took control of the island. It is still the language of education and administration, reflecting more than 100 years of Spanish colonial rule. 67% of Equatoguineans can speak Spanish, especially those living in the capital, Malabo, on Bioko.

The Bube language, with about 50,000 speakers and various dialects, is the original language of the inhabitants of Bioko. However, given the numerous ethnic groups and peoples who operated on Bioko, a creole language developed, known as Pichi. It is based on English grammar from the period when the British operated bases for their forces. It also incorporates West African languages from Nigeria and Liberia, as well as Portuguese vocabulary, which forms a considerable part of the Krio language, which had developed in Sierra Leone. Workers came to Bioko from all of these areas in the 19th through much of the 20th century.

History

Unlike other islands in the area, Bioko had an indigenous African population. The island was inhabited in the middle of the first millennium BC by Bantu tribes from the mainland, who formed the Bubi ethnic group. The Bubi speak a Bantu language. The island has probably been inhabited by this or other Bantu-speaking groups since before the 7th century BC.

In 1472, the Portuguese navigator Fernão do Pó was the first European to sight the island. He named it Formosa Flora ("beautiful flower"). In 1494, it was renamed Fernando Pó in his honour after the Portuguese claimed it as a colony. The Portuguese developed the island for sugarcane cultivation. Although the sugar was considered of poor quality, the refineries' output was sufficient for Fernando Pó sugar to dominate the trade centers in Europe briefly.

In 1642, the Dutch East India Company established trade bases on the island without Portuguese consent. It temporarily centralized from there its slave trade in the Gulf of Guinea. The Portuguese appeared again on the island in 1648, replacing the Dutch Company with one of their own, also dedicated to slave trading and established in its neighbour island Corisco.

In parallel with this establishment, the Bubi clans began the slow process of building the core of a new kingdom on the island, especially through the activities of some local chiefs, such as Molambo (approx. 1700–1760). During a period when enslavement was increasing in the region, local clans abandoned their coastal settlements and settled in the safer hinterland.

Under the 1778 Treaty of El Pardo, Portugal ceded Fernando Po, Annobón, and the Guinea coast, Río Muni, to Spain, which together form modern Equatorial Guinea. The treaty was signed by Queen Mary I of Portugal and King Charles III of Spain, in exchange for territory on the American continent. Spain mounted an expedition to Fernando Po, led by the Conde de Argelejos, who stayed for four months. In October 1778, Spain appointed a governor for the island, who remained until 1780, when the Spanish mission left.

Chief Molambo was succeeded by another local leader, Lorite (1760–1810), who was succeeded by Lopoa (1810–1842). After abolishing the British Atlantic slave trade, the British leased bases at Port Clarence (modern Malabo) and San Carlos for the Preventive Squadron from 1827 to 1843. The settlement at Port Clarence (named after the Duke of Clarence) was constructed under the supervision of William Fitzwilliam Owen. He had previously mapped most of Africa's coasts and was a zealous anti-slaver. During his three-year command, his forces detained 20 ships and liberated 2,500 enslaved people. The Mixed Commission Court was moved from Freetown, Sierra Leone, to Clarence to hasten the legal process of emancipating enslaved people liberated from slave ships.

In March 1843, Juan José Lerena planted the Spanish flag in Port Clarence (renamed Santa Isabel), starting the decline of British influence on the island. Spain revoked the British lease in 1855. Madabita (1842–1860) and Sepoko (1860–1875) were principal local chiefs during the period when Spain re-established its control of the island. A notable resident from 1861 to 1865 was the British explorer Richard Burton, who served as the British consul, during which time he wrote several books about Africa. This period was also marked by Spain's deportation of several hundred Afro-Cubans, as well as dozens of Spanish scholars and politicians considered politically undesirable. In addition Spain exiled 218 revolutionaries here from the Philippine Revolution, of whom only 94 survived for long.

In 1923–1930, the League of Nations investigated the transportation of contract migrant labour between Liberia and the Spanish colony of Fernando Po. Although the League concentrated its attention on arrangements in Liberia, a closer examination revealed that labour abuse arose from conditions on Fernando Po. In the last quarter of the 19th century, Krio planters on the island had shifted from palm oil trading to cocoa cultivation. Their dependence on migrant labour and increasing competition with Europeans led to an economic crisis in the early years of the twentieth century. Planters retained labour but failed to pay their contracts, resulting in a situation of de facto slavery. Liberia prohibited labour traders from contracting with its citizens.

In 1942, Fernando Pó was the scene of a small-scale, secret British raid code-named Operation Postmaster, which sought to disrupt German U-boat resupply activities on the island.

During the Nigerian Civil War in the 20th century, relief agencies used the island as one of the bases for Biafran airlift flights into the secessionist Republic of Biafra.

In 2025, the island was designated as a biosphere reserve by UNESCO.

Economy

Located on Punta Europa, west of Malabo, the Alba Gas Plant processes natural gas delivered from offshore production wells. The plant is operated by Marathon Oil Company through its subsidiary, Marathon Equatorial Guinea Production Limited. The plant produces natural gas liquids including propane, butane, and condensate products. The majority of the residue gas from the Alba plant is delivered to a natural gas liquefaction plant operated by EG LNG. A portion of the Alba plant residue is also delivered to the Atlantic Methanol Production Company and is used to produce methanol. The products from all three plants are loaded onto ocean-going tanker ships for export.

Transport

A rectangular transport route links the four main cities: Malabo, Luba, Baney, and Riaba. The island's airport is Malabo International Airport.

Tourism

Tourist attractions include the colonial quarter in Malabo, and the southern part of the island, where visitors can hike to the Iladyi Cascades (Moka Falls) and to remote beaches of Ureka to watch nesting turtles.