Tara anchors at Huon Atoll

© Vincent Hilaire / Tara Expeditions Foundation

6 October 2017

With the Guilbert and Merit reefs, Huon is one of the 4 atolls that make up the Entrecasteaux nature reserve. This paradise of biodiversity, declared a World Heritage Site by UNESCO in July 2008, is a sanctuary for birds, green turtles, 2,300 species of fish and more than 350 different corals.

We are here on mission until October 13 with scientists from the Institute of Research and Development (IRD) in Noumea and the University of New Caledonia (UNC). They will investigate the guano of the thousands of birds present on these islets.


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A coastal crab on Huon Island, in the reefs of Entrecasteaux – © Vincent Hilaire / Tara Expeditions Foundation


The Entrecasteaux reefs are flush with the surface and are located northwest of New Caledonia about 180 kilometers from Grande Terre. Uninhabited, they constitute the northern limit of the New Caledonian archipelago.
They were discovered on July 1st, 1792 by Antoine Bruny d’Entrecasteaux with two armed frigates sent by Louis XVI in search of the expedition led by La Pérouse.

Entrecasteaux could not find traces of La Pérouse and the expedition ended chaotically in Surabaya. The ships passed close to Vanikoro where survivors of the Boussole and Astrolabe shipwrecks were certainly still alive, but off Java’s coast on July 20th, 1793, Entrecasteaux succumbed to scurvy.

This trip was nonetheless a success because many unknown lands, including these reefs were discovered for France.


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For the crew of Tara, the days ends with a magnificent sunset over the Pacific – ©  Vincent Hilaire / Tara Expeditions Foundation


An anecdote: the name ‘Surprise Atoll’ comes from the fact that Entrecasteaux was amazed to discover an uncharted reef so close to the Grande Terre, thinking he had completely circled New Caledonia.

The other 3 Entrecasteaux reefs are named for expedition members: Jean-Michel Huon of Kermadec, commander of L’Esperance; the lieutenant of the Malo de la Motte du Portail; and the lieutenant du Mérite. The Guilbert reef is named after the hydrographer of the Jules Dumont d’Urville expedition in 1827.

The area was regularly frequented by whalers in the early 19th century. But continuous occupation took place only on the 3 islets of the Surprise Atoll between 1883 and 1928, for the exploitation of guano.


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Entrecasteaux is a bird sanctuary, as we can see on Huon Atoll – © Vincent Hilaire / Tara Expeditions Foundation


This exploitation has ceased, but today scientists are interested. After the bleaching in February 2016 that seriously impacted Grande Terre and the Entrecasteaux reefs, they are trying to understand why these atolls are affected differently.

During this last bleaching episode, 90% of the Entrecasteaux lagoon reefs were impacted between the surface and 5 meters. But exterior to the lagoon only about half were affected.

This brought up the hypothesis that guano might be an influence. Thanks to the mission on these reefs with Tara and her crew, the teams of the IRD and the UNC are hoping to finally unlock the secrets of Entrecasteaux coral resilience.

Since Tuesday, the teams have been working together to take coral samples, hunt reef fish and collect valuable droppings ashore to try and confirm the key role played by guano on coral communities underwater. The results of this research will certainly make history.

Vincent Hilaire

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