With the exception of two or three months in summer, this flat island is swept day and night by heavy winds that are sustained in winter.

Veloutaries (Heliotropium foertherianum) and purslane (Portulaca oleracea), with growth shaped by dominant east winds, are present everywhere on the island.

The fauna consist mainly of hermit crabs (Paguroidea), seabirds, and sea turtles for which the island is an important nesting place.

The island has been identified as an Important Bird Area (IBA) by BirdLife International because of its significance as a seabird breeding site.

The island's masked boobies are of the western Indian Ocean subspecies (Sula dactylatra melanops), of which Tromelin is a stronghold.

A navigation error, due to the use of two conflicting charts, caused the vessel to wreck on the reefs of Tromelin Island (then called the Isle of Sand).

Castellan built two camps, one for the crew and one for the slaves, a forge and an oven, and with the materials recovered from the wreckage, began construction of a boat.

However, they met with a categorical refusal from the governor, with the justification that France was fighting the Seven Years' War and thus no ship could be spared, the island of Mauritius being itself under threat of attack from British India.

The news of the castaway slaves got published and stirred the Parisian intellectual milieu; later, the episode was all but forgotten with the end of the Seven Years' War and the bankruptcy of the East India Company.

[17] In 1773, a ship passing close to Tromelin Island located the slaves and reported them to the authorities of Isle de France.

This sailor remained on Tromelin Island and, some time later, probably around 1775, built a raft on which he embarked with three men and three women, but which disappeared at sea.

[17] It was not until 29 November 1776, 15 years after the sinking, that Ensign Tromelin-Lanuguy, captain of the corvette Dauphine,[2] reached Tromelin Island and rescued the survivors – seven women and an eight-month-old child.

[5][18] Upon arriving there, Tromelin-Lanuguy discovered that the survivors were dressed in plaited feather clothes and that they had managed, during all these years, to keep a fire lit (the island did not have a single tree).

The Malagasy people, who had been left on the bleak little island, built a shed with coral stones, for most of the wood had been used in the construction of the raft for the crew.

[15] The survivors remained with Jacques Maillart, governor of Mauritius (Isle de France), who declared them free and offered to bring them back to Madagascar, which they refused.

[17] An archeological expedition entitled "Forgotten Slaves", led by Max Guérout, a former French naval officer and director of operations of the Naval Archeology Research Group, and Thomas Romon, archaeologist at INRAP (National Institute for Preventive Archaeological Research), took place from October to November 2006, under the patronage of UNESCO and the French Committee for the History and Remembrance of Slavery (CPMHE).

The ten members of the expedition probed the wreck of Utile, and searched the island for traces of shipwreck, in order to better understand the living conditions of the Malagasy people during these fifteen years.

Basements made of beach sandstone and coral were also found (the survivors thus transgressed a Malagasy custom according to which stone constructions were reserved for tombs).

It allowed the discovery of three new buildings and many objects, including two tinder lighters and flints, which elucidated the technique used by the castaways to rekindle the fire.

[19] Indeed, the treaty does not specifically mention all the dependencies of Mauritius, which leads to uncertainty on the sovereignty of Tromelin, and the official text was that written in French.

The Mauritian claim to sovereignty is based on the fact that the island must have been ceded to United Kingdom by the treaty of Paris in 1814 and should not continue to be administered by France as a dependency of Réunion.

The island's autonomous weather station, which warns of cyclones, is still operated by France and is supported by personnel from the French Southern and Antarctic Lands (TAAF).