Two remote volcanic islands in the Indian Ocean host a fragile, struggling subantarctic ecosystem.

Nature · Published 30 September 2026 Swipe more like this →

In short: The Prince Edward Islands are a pair of uninhabited, wind-battered volcanic outposts administered by South Africa. Once a hub for sealers and whalers, these islands now serve as a critical laboratory for climate and biological research, though invasive species continue to threaten their unique and vulnerable native wildlife.

Located roughly 1,769 kilometers southeast of South Africa, the Prince Edward Islands consist of Marion Island and the smaller Prince Edward Island. Both are volcanic in origin; Marion Island is the peak of a massive underwater shield volcano rising 5,000 meters from the sea floor. Despite their temperate latitude, they experience a harsh tundra climate characterized by constant wind, heavy rainfall, and frequent cloud cover, which has limited the native flora to just 22 vascular plant species.

The islands are a vital sanctuary for seabirds, supporting an estimated 8 million individuals, including five species of albatross. However, human activity has left a lasting ecological footprint. In the 1800s, sealers introduced house mice, which have since reached plague-like levels. After a 20th-century effort successfully eradicated introduced cats—which had been brought in to control the mice but instead decimated local petrel populations—the mouse population exploded. Researchers have since observed these mice attacking and eating albatross chicks alive, prompting urgent discussions regarding a potential eradication program.

Beyond biology, the islands hold a complex geopolitical and scientific history. Annexed by South Africa in 1948, they host a permanent research station that monitors everything from meteorology to cosmology. The islands were also the site of the 1979 'Vela incident,' an unexplained double flash of light detected by a U.S. satellite that remains a subject of controversy, with many researchers suspecting an undeclared nuclear test. Today, the islands are protected as a Special Nature Reserve, with 180,000 square kilometers of surrounding ocean designated as a Marine Protected Area to safeguard the region's biodiversity.

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