In 2004, Jean-Louis Étienne led a pioneering mission to Clipperton Atoll to inventory its biodiversity. In 2025, accompanied by expedition director Elsa Peny-Étienne, he returned to this Pacific “rock” aboard the oceanographic sailboat Persévérance.

This mission unfolded within a dual timeframe: that of family memories—when their sons Ulysse and Elliot discovered the atoll as children—and the more serious one of recognizing an ecosystem in peril.

The 2025 mission focused on three major pillars to guarantee the future of French biological sovereignty in the Pacific:

Extension of the Marine Protected Area: Securing feeding grounds at sea for the Masked Booby, for which Clipperton is home to the world’s largest colony.

Terrestrial Restoration (Rat Control): Launching, with the LPO (League for the Protection of Birds), the process of eradicating black rats. Accidentally introduced, they are the driving force behind a major imbalance.

Waste Observatory: Analyzing the proliferation of microplastics, grim witnesses to the circulation of global currents that wash up on this isolated shore.

An Inverted Trophic Cascade: the atoll’s image has radically changed in two decades. Against all odds, the island has become “green.” What might seem like a sign of health is actually a symptom of a disruption in the food chain. By consuming land crabs, the rat has eliminated the island’s natural “gardeners.” Without crabs to regulate growth, grasses and coconut palms are invading the reef flat. And the masked boobies, which absolutely need bare, dry soil to nest, are seeing their habitat disappear under the vegetation.