Fiji's geography: two volcanic islands split by their rainfall

How many islands make up Fiji

The answer depends on who is counting and where the line between an island and an islet is drawn. The Wikipedia geography of Fiji gives 332 islands, about 106 of them permanently inhabited, and 522 smaller islets. Australia's foreign ministry, in its country brief, gives 322 islands. The Commonwealth Secretariat rounds to about 300 islands, about 100 of them inhabited, and Britannica gives about 300 islands and 540 islets. None of the four is wrong on its own terms, and none of them says which reef or rock was counted.

The land is small and the sea around it is large. Less than 2% of the archipelago's extent is dry land, and the exclusive economic zone is 1.26 million square kilometres in the Australian brief and 1,282,978 square kilometres in the Wikipedia figure. The group lies about 2,000 kilometres north-north-east of New Zealand. Two outliers sit well away from the rest: Rotuma, a Polynesian island of about 44 to 47 square kilometres some 400 kilometres to the north, which has its own council as a dependency, and Ceva-i-Ra, or Conway Reef, an uninhabited coral cay about 450 kilometres to the south-west.

The outer groups each have their own character. The Lau islands lie east across the Koro Sea, close enough to Tonga that Britannica records a long history of intermarriage between Lau and Tongan families; the Lakeba Passage separates the two. The Mamanuca and Yasawa groups run north-west from Nadi. The Lomaiviti group sits off Suva, with Ovalau and Levuka. Many Banabans settled on Rabi, off the east coast of Vanua Levu, after leaving their own island, now part of Kiribati, after damage in the Second World War made it uninhabitable.

The 180th meridian runs through Taveuni. The international date line is bent around the group so that every island keeps the same time, twelve hours ahead of Greenwich, and the whole country sits in one zone.

What made the islands

Fiji stands on a submerged platform of old formation, and Britannica describes the islands as the product of three processes: volcanic action, sedimentary deposit and the growth of coral. Volcanic activity began about 150 million years ago. The group lies near the north-east corner of the Indo-Australian plate, on the North Fiji Basin between two fracture zones, close to where that plate goes under the Pacific plate.

Some heat is still coming up. Geothermal activity continues on Vanua Levu and Taveuni. The hot springs of Viti Levu are of a different kind, non-volcanic in origin, with surface water between about 35 and 60 °C. Many of the smaller islands, including the Lomaiviti, Lau and Yasawa groups, are volcanic too. Levuka, the first colonial capital, is built on the beach front of Ovalau below the forested slopes of the island's extinct volcano.

Coral reefs, offshore rocks and shoals ring almost every island. Britannica notes that they make the Koro Sea, the stretch of water in the middle of the group, hazardous to navigate. The reef also explains a feature visitors notice: much of the shoreline is reef and rock, white-sand beaches are few, and the encircling reef leaves little surf.

How Viti Levu's range divides the main island

Viti Levu, "Great Fiji", covers 10,429 square kilometres in Britannica's figure, more than half the country's land. A jagged range runs through it from north to south, with several peaks above 900 metres, among them Tomanivi, formerly called Mount Victoria, the country's highest point. The four main rivers, the Rewa, the Navua, the Sigatoka and the Ba, all rise in that central mountain block.

Where the range divides, and on its south-eastern and south-western flanks, the mountains step down to plateaus and then to lowland. The coastal plains in the west, north-west and south-east cover less than a fifth of Viti Levu, and they hold most of its farms and towns. The fertile valleys and deltas of the Navua, Rewa and Sigatoka grow sugar, pineapples, rice and tobacco. In the north-central interior a goldfield at Vatukoula was first worked in the 1930s. The island's coasts carry its connections: the main international airport at Nadi in the west, an oil-fuel installation at nearby Vunda Point, and a smaller international airport at Nausori, north-east of Suva, which mostly handles domestic flights. Roads link Suva and Nadi, about 210 kilometres apart.

The government divides the country into four divisions, Central, Eastern, Northern and Western, each run by a commissioner and split into a total of 14 provinces with their own councils. Rotuma stands outside that pattern as a dependency.

Vanua Levu, the second island, covers about 5,540 square kilometres and lies 64 kilometres north-east of Viti Levu. A mountain range runs along its length, and its northern coastal plains are narrow except near the mouth of the Dreketi River. Natewa Bay cuts deep into the north-east and shapes the Loa peninsula.

Why the western lowlands stay dry

Rain falls on the windward, south-eastern sides of the large islands, and the mountains shelter the west. Britannica gives the eastern sides of Viti Levu and Vanua Levu about 3,000 mm of rain a year and the western sides about 1,800 mm. Its entry on Viti Levu puts the dry north-west at 1,800 to 2,300 mm. In the east rain falls less from April to October; in the west it almost stops.

That difference is the main fact of Fijian farming. The lowlands in the west of each large island, sheltered by the mountains, have a marked dry season that suits sugarcane, and the Fiji Sugar Corporation's cane is grown on the western belt of Viti Levu and around Labasa on Vanua Levu. The wet south-eastern sides carry dense tropical forest instead. Dry grasslands appear in the west of the large islands, and mangrove swamps fringe the eastern coasts.

Temperatures change little. At Suva the average summer high is about 29 °C and the average winter low about 20 °C, according to Britannica, with cooler air in the inland hills. The warm season runs from November to April and the cooler one from May to October; the cool season averages about 22 °C in the Wikipedia climate summary. El Niño and La Niña years shift the rainfall noticeably.

How cyclones reach the islands

The wet season is also the cyclone season. Britannica says tropical cyclones arrive between November and March perhaps once every two years. The Wikipedia figure is higher, about one a year or 10 to 12 a decade. The two sources do not say what they count as reaching Fiji.

Severe Tropical Cyclone Winston, a Category 5 storm, crossed Fiji on 20 and 21 February 2016. The government estimated that almost 350,000 people lived in its path. By 29 February 2016 the United Nations Office for the Coordination of Humanitarian Affairs recorded at least 42 deaths and about 56,000 people in evacuation centres, and in March 2016 the government revised the count of damaged houses to 32,000. The post-disaster needs assessment prepared by the government and its partners put damage and losses at $1.42 billion, equal to 31% of gross domestic product, and the storm damaged at least 495 schools and 88 health facilities. Recovery was slow and uneven. The number of people in evacuation centres fell from 54,000 on 3 March 2016 to 337 on 31 March 2016, but 20 of the 26 centres still open were on Ovalau, and by the end of March only 500 of the 7,500 households targeted for repair materials had received them. The government estimated that 150,000 people needed help with shelter. In June 2016 the Asian Development Bank announced a $50 million emergency loan for rebuilding schools and housing. Cyclone Harold caused widespread damage again a few years later.

Rising seas are the slower risk. The Wikipedia climate section expects sea-level rise, coastal erosion and extreme weather to displace communities, and Fiji, a party to the Kyoto Protocol and the Paris Agreement, aims for net-zero emissions by 2050.

Where the forests and reefs remain

Almost half of Fiji's total area is still forested, in the figure both Britannica and the Commonwealth Secretariat give. Global Forest Watch, working from satellite imagery, records a tree cover extent of 1,556,562 hectares in 2000 and a cumulative loss of 54,074 hectares between 2001 and 2024, about 3.5% of that baseline; regrowth is not counted. Two forest ecoregions are recognised, Fiji tropical moist forests and Fiji tropical dry forests.

The wildlife is island wildlife. The Fiji banded iguana, the Fiji crested iguana and the many-coloured fruit dove live there. Several species are known only as fossils, including a crocodilian of the genus Volia, a giant iguana, Lapitiguana impensa, and a flightless giant pigeon on Viti Levu. Most larger animals now on the islands, pigs, dogs, cattle and a few horses, are domesticated, and the mongoose, brought in to hunt snakes and rats, is common.

Where people live on the land

The interior of Viti Levu is thinly settled because of its terrain. Most people live on the coast, and about half the population lives in towns, with Suva holding about a quarter of the total, according to Britannica. Suva was founded in 1849, became the capital in 1882 when the government moved from Levuka, and became a city in 1952. It sits on Suva Point between the mouth of the Rewa and Suva Harbour. Lautoka, on the north-west coast, is the sugar port, and Nadi, on the dry west side, has the main international airport. Labasa is the administrative and sugar town of Vanua Levu.

Levuka shows how a town was fitted to this kind of shore. A stone and concrete sea wall runs the length of Beach Street, and lanes branch inland in a radial pattern that follows the contours, between three creeks draining the slopes above a narrow coastal plain. UNESCO, which inscribed the town on the World Heritage List in 2013, notes that the cliff terrain behind it is vulnerable to storm damage. Suva grew on a harbour that became a regular stop for transpacific shipping, and its suburb Nasinu grew fast in the late 20th and early 21st centuries.

The population has grown slowly for half a century. The Fiji Bureau of Statistics counted 121,180 people at the census of April 1891 and slightly fewer, 120,124, in 1901. The total passed 259,638 in 1946 and 476,727 in 1966, then slowed: 775,077 in 1996, 837,271 in 2007 and 884,887 at the census of 17 September 2017, growth of 0.6% a year over the last decade measured. The same census found 10.4% of the population under five years old. On the smaller islands and in the remoter parts of the large ones, iTaukei families live in villages on land held by their clans, while the sugar districts of western Viti Levu and Vanua Levu are mostly Indo-Fijian.