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Kermadec Islands

by Simon Nathan

The subtropical, volcanic Kermadec Islands are the northernmost part of New Zealand. Attempts were made to settle on Raoul Island from the 1830s, but the isolation, lack of fresh water and occasional volcanic eruptions made it a difficult place to live. In the 2000s the islands are a nature reserve, and eradication of pests was allowing bird and plant life to regenerate.


Geology and climate

The Kermadec Islands are a group of small volcanic islands, 800–1,000 kilometres north-east of the North Island. The largest, Raoul Island, is 29 square kilometres in area, but all the other islands are small and collectively cover less than 4 square kilometres. The islands are strategically important, however, as they define the northern extent of New Zealand’s Exclusive Economic Zone (EEZ) and Extended Continental Shelf (ECS).

Comparing islands

At 29 square kilometres Raoul Island is larger than Kapiti (19.6 sq km), about half as big as Manhattan (59 sq km) and three-eighths the size of Hong Kong island (80 sq km).

All the Kermadec Islands are part of a specially designated nature reserve, so a permit from the Department of Conservation is required to set foot on land. The surrounding seas are also protected by the Kermadec Islands Marine Reserve, which extends for 12 nautical miles from the coastline of each island. It covers an area of 7,450 sq km, the coastal parts of which are rich in marine life, despite a lack of nutrients in the surrounding ocean. The surprising amount of sea life may be due to tidal movements that disturb water to a great depth, bringing nutrients to the surface. Both onshore and offshore reserves are currently under consideration as a World Heritage Area.

The islands are uninhabited, except for Raoul, where a field station is maintained by the Department of Conservation. Staff and volunteers collect meteorological and seismic information, control weeds and supervise the marine and nature reserves.

Climate

With a mild, subtropical climate, the islands have average temperatures ranging from 16.0°C (August) to 22.4°C (February). Total annual rainfall is approximately 1,500 mm, spread through the year, with occasional cyclones.

Being subtropical rather than tropical, the Kermadec Islands are close to the southern limit for most coral species. There are no coral reefs, and only individual corals are found on the sea floor, mainly in shallow clear water.

Lucky escape

In 1954 the British government requested permission to test a hydrogen bomb in the Kermadec Islands. Although there had been eruptions in 1814 and 1870, no one recognised that Raoul was an active volcano. Indeed, the central flat area surrounded by steep cliffs (now recognised as the Raoul caldera) seemed an excellent testing spot. Fortunately the request was declined by the New Zealand government – for political rather than scientific reasons.

Volcanoes on the Kermadec ridge

The rocks of the Kermadecs are no more than 1 million years old, and some of the youngest have been erupted within the last few hundred years. The islands are the only part above sea level of a chain of huge submarine volcanoes. Mapping of the sea floor since 1998 has shown that a north-east-trending line of 40 volcanoes (Kermadec ridge) extends between New Zealand and Tonga. These volcanoes mark the collision zone between two tectonic plates, where the Pacific plate is being subducted (pushed down) beneath the Australian plate, causing melting deep in the crust. Large earthquakes occur on or close to the plate boundary.

Some of the volcanoes are still active, and submarine eruptions are a hazard because of the ejection of ash clouds. Both volcanic eruptions and earthquakes on the Kermadec ridge have the potential to generate tsunamis. At least three earthquakes of more than magnitude 7 took place along the Kermadec ridge in the second half of 2011 alone.


Plants and animals

The Kermadecs are true oceanic islands that have never been joined to nearby land masses. When volcanoes emerged from the sea they were bare, and all plants and animals that are now found there had to travel across the ocean or be transported. A distinctive fauna and flora has gradually developed over thousands of years.

Vegetation

Native vegetation is found on all the islands, but it is locally modified by weeds introduced by humans. On Raoul, the only forested island, the dominant canopy species are the Kermadec pōhutukawa (Metrosideros kermadecensis) and the Kermadec nīkau (Rhopalostylis baueri var. cheesemanii), with an understorey of small trees, shrubs and ferns. Māpou is widespread in coastal areas up to 250 metres above sea level, replaced at higher altitudes by hutu.

113 native species or subspecies of vascular plants, of which 23 are endemic, are found in the Kermadecs. The flora is largely derived from New Zealand, and many of the endemic forms have evolved from New Zealand species. The plants that have colonised the islands are well adapted to natural disturbances such as cyclones, landslides and volcanic eruptions.

Birds

The Kermadec Islands have no native land mammals, but are home to large colonies of seabirds which nest in the forests or on the coast. 35 bird species are known, at least three of which are unique to the Kermadecs. Important species include the red-tailed tropic bird, the Kermadec parakeet, the masked booby and distinctive species of noddies and terns.

Four seabird species migrate annually to the North Pacific after the breeding season, but the remainder are confined to the South Pacific or do not travel far from their nesting grounds.

Within the forest on Raoul Island the New Zealand tūī is the most common species.

Introduced plants and animals

The introduction of goats, cats and rats to Raoul and Macauley islands had a disastrous effect on both the vegetation and the bird population. A range of exotic plants was introduced to Raoul by settlers, and some of these have spread widely in the warm climate and become weeds. The tī pore (tropical cabbage tree) was probably introduced to the islands by Polynesian voyagers to New Zealand.

Army worms at work

An aroid lily (Alocasia brisbanensis) was introduced to Raoul Island in the 19th century, and has spread explosively to cover the forest floor. There seemed to be no way to remove this weed. But an unexpected consequence of rat eradication was the emergence of the tropical army worm – which is now defoliating the lily plants.

Goats, cats and rats have all been eradicated from both islands in recent years, and there has been an immediate increase in the number and diversity of birds. The Kermadec parakeet has reappeared on Raoul, and new seabird colonies have been established.

Volunteer groups have worked since the 1980s to eradicate weeds from Raoul Island, with considerable success. Work continues to control and eventually remove persistent species such as Mysore thorn, guava, passionfruit and buttercup plant.


Human impact

Polynesian voyagers

The first people to visit the Kermadec Islands, from the 1300s onwards, were of Polynesian origin. A number of cultural layers, including ovens and stone tools, have been found during archaeological investigations on Raoul Island. The tools were mainly made from local materials, but distinctive obsidian flakes from Tūhua (Mayor Island) in the Bay of Plenty have also been found, indicating that the islands were a stopping point for two-way travel between New Zealand and the Polynesian homeland. It is likely that the kiore (Polynesian rat) was introduced to the Kermadecs in this period.

According to Māori tradition, the Aotea and Kurahaupō canoes visited the Kermadecs as they travelled southwards to New Zealand. The Kurahaupō was badly damaged on a reef, so many of the crew transferred to the Aotea for the final stage of the journey. Eventually the Kurahaupō was repaired, and sailed southwards to land in Northland. The Māori name for the Kermadecs is Rangitāhua.

European discovery

The Kermadec group was first charted by the French explorer Antoine Raymond Joseph de Bruni d’Entrecasteaux, in command of the Recherche and Espérance in 1793. He named the island chain after the captain of the Espérance, Huon de Kermadec.

A better Brittany?

Kermadec is a common place name in the French province of Brittany, meaning the place or village of Madec. There are no other Kermadecs in the Pacific, but Huon (de Kermadec’s Christian name) is a place name in both Tasmania and Papua New Guinea.

The first Europeans to land on the Kermadecs were almost certainly whalers, from the 1790s onwards. Ship-based whalers, predominantly French or American, called at Raoul Island to get water and firewood for rendering whales at sea. Goats were liberated on Raoul and Macauley islands to establish populations as a source of fresh meat for visiting ships. In 1878 Thomas Bell and his family settled on Raoul Island; it was to be their home for 35 years.

Annexation

Through most of the 19th century the Kermadec Islands were not claimed by any country. After Germany attempted to annex Samoa in 1885, the New Zealand colonial government, concerned that the islands might fall into foreign hands, urged the British authorities to act. On 31 July 1886 Captain F. S. Clayton of HMS Diamond hoisted the British flag on Raoul Island; the islands were annexed by New Zealand a year later. Following the annexation a government expedition aboard the HMS Stella spent a week in the Kermadecs, raising the New Zealand flag on 17 August. Expedition members – naturalist Thomas Cheeseman and government surveyor S. Percy Smith – duly reported back to the government and the public on aspects of the islands. Sections of land on Raoul Island were offered for sale. Settlers came in 1889, but a year later all had left, with the Bells again the only inhabitants. The first major scientific expedition, led by W. R. B. Oliver, visited the island group in 1908.

A workers’ paradise?

Not everyone was persuaded of the merits of annexing the Kermadecs. ‘It is always fine,’ commented a spoof report on the island group in 1886, ‘except when it rains, and when there is no wind a delicious calm prevails … the Government have consented to give a Crown grant of the Islands on the sole condition that the Company takes all the unemployed from New Zealand, and pay them a pound a day (paper currency). The working day in the Kermadecs consists of two hours, out of which sixty minutes are allowed for smoke and an equal portion for repose.’1

Wartime haven

During the First World War the deserted Kermadec Islands were used as a haven by the German raider Wolf in 1917. Later that year the castaway depot on Curtis Island was used by the escaped prisoner of war Count Felix von Luckner before he was captured and returned to captivity in New Zealand.

The islands were kept under close observation by coastwatchers stationed on them during the Second World War. A radio and meteorological station was established on Raoul Island by the New Zealand government in 1939. Since 1988 the islands have been managed by New Zealand’s Department of Conservation.

Footnotes
  1. Daily Telegraph, 7 July 1886 (reprinted from the Evening Press), http://paperspast.natlib.govt.nz/cgi-bin/paperspast?a=d&cl=search&d=DTN18860707.2.13&srpos=1&e=-------10--1----2+working+day+in+the+Kermadecs+-- (last accessed 20 August 2012). Back

Raoul Island

The island was named after Joseph Raoul, quartermaster of the Recherche, when it was sighted on 16 March 1793. It was later seen on 6 March 1796 by Captain W. Raven of the whaler Britannia. He called it Sunday Island, a name which was subsequently in common usage. The island was charted by Captain H. M. Denham of HMS Herald in 1854.

When the New Zealand government established a weather and radio station on the island in 1939 it made Raoul the official name, probably to avoid confusion with a number of Sunday islands in Australia.

Although Raoul is the only island in the Kermadec group large enough to support settlement, it lacks a safe harbour, and landings from small boats can only be made in calm weather. The island consists of two mountainous areas, one with summits of 516m and 498m, and the other with a summit of 465m, the two separated by a depression which is the caldera of the Raoul volcano.

An active volcano

Raoul Island is the emergent part of a large submarine volcano, and its irregular, anvil-like shape is due to a combination of volcanic activity and erosion. Layers of pumice and ash mantling the island indicate that there have been sporadic explosive eruptions for at least the last 4,000 years, and similar large eruptions are likely in the future.

Two collapse calderas, Raoul and Denham, have been the site of volcanic eruptions since the early 1800s. Recent bathymetric investigations have revealed the presence of additional submarine calderas a few kilometres north-west and south-west of the island.

Explosive eruptions occurred in the Raoul caldera in 1814, 1870, 1964 and 2006. The first two eruptions were accompanied by the appearance in Denham Bay of volcanic islands which were later eroded away by the sea.

A sad end

In 1860 a ‘blackbirding’ captain offloaded at Raoul Island a number of Tokelauans destined for forced labour in Peru, because they were sick with an infectious illness. Not only did they die, so did some of the island’s inhabitants who cared for them.

European occupation

A small number of families settled on the island from the 1830s onwards, eking out an existence by selling provisions to visiting ships, but all left after the 1870 eruption.

Thomas Bell and his family moved to Raoul Island from Samoa in 1878, and their difficult life on the island for the next 35 years is recorded in Elsie K. Morton’s Crusoes of Sunday Island. Initially living at Denham Bay, they later moved to North Beach. There, with the assistance of a group of visiting Niuean workers (Niue was the closest Pacific island after Tonga), they were able to clear an area of bush and establish large gardens. The Niueans were paid in kind as the Bells did not have any cash. Helped by former New Zealand governor George Grey, the Bells introduced a variety of fruit trees and other plants, some of which spread and became regarded as pests.

After annexing the islands, the New Zealand government allocated Thomas Bell just 275 acres (111 hectares) of land. Bell claimed ownership of the whole island and lobbied unsuccessfully to that end until his death.

Groves of oranges and other fruit trees were planted in the 1930s, but the venture failed because of the lack of a safe landing place from which to export the produce. The meteorological station is on a flat terrace on the northern side of the island, and has been continuously occupied since 1939.

A prickly problem

Mysore thorn was introduced from India as a hedging plant to keep goats out of the vegetable gardens. It subsequently spread over a large area in Denham Bay, and has proved one of the most difficult and unpleasant plants to eradicate.

North-eastern islands

A small group of tiny islands immediately north-east of Raoul (Meyer, Herald, Napier and Nugent islands) have never been modified by introduced mammals, so have retained their original bird populations. With the removal of rats, cats and goats from Raoul Island, some of the species that had become extinct there are gradually being re-established from populations preserved on the north-eastern islands.


Southern Kermadec Islands

The southern Kermadec Islands were first sighted from the convict ship Lady Penrhyn on 31 May 1788. Macauley Island is situated about 110 km south-west of Raoul Island and Curtis Island a further 35 km south again. Captain Sever landed on the larger island, which he named (although with a different spelling) after Alderman George Mackenzie Macaulay of London. Curtis Island was named after Timothy and William Curtis, the ship’s owners.

The islands’ small size, difficult access and lack of water has deterred human settlement. The New Zealand government established castaway depots on Macauley and Curtis islands and L’Esperance Rock (80 km further south again) soon after the Kermadecs were annexed.

Macauley Island

Macauley Island is a tiny part of a large submerged volcanic complex which includes a 10-km-long caldera and an elongated dome dotted with tiny volcanic cones. The island covers only 3 square kilometres (including adjacent Haszard Island), and represents the gently sloping flank of a broad volcanic cone which has partly disappeared due to collapse and erosion.

Cliffs at the north end of the island expose a spectacular section across the volcano, including white Sandy Bay ignimbrite, probably erupted from the nearby caldera several thousand years ago.

The island was originally covered with native forest, but fires and browsing by introduced goats changed the land to a rolling grassy meadow. Now that goats have been eradicated the vegetation is slowly returning, and bird numbers have greatly increased.

Curtis Island

French fields

The slaughter of sperm whales near the Kermadecs boomed in the early 19th century. At its height in the 1830s, up to 30 vessels could be seen in a single day near L’Esperance Rock, and the area became known as the French Rock whaling grounds.

A line of large pink barnacles 18 metres above sea level is an indication that the islands are rapidly rising. Bathymetric surveys indicate 7 metres of uplift between 1929 and 1964, and the bay where small boats previously landed is now above sea level.

Cheeseman Island is named after Thomas Cheeseman, the naturalist on the 1887 expedition to the Kermadecs, and Stella Passage between Curtis and Cheeseman islands is named for the expedition ship.


External links and sources

More suggestions and sources


How to cite this page: Simon Nathan, 'Kermadec Islands', Te Ara - the Encyclopedia of New Zealand, http://www.TeAra.govt.nz/en/kermadec-islands/print (accessed 15 October 2019)

Story by Simon Nathan, published 12 Sep 2012