At Darwin and Wolf islands, critically endangered scalloped hammerheads still gather in thousands — but only because researchers are learning to study them without touching them.
On a March morning off Darwin Island, at the northernmost edge of the Galápagos marine reserve, Carlos Robalino holds his breath and descends with a metal pole-spear toward a two-metre scalloped hammerhead. The spear grazes the shark's flank, collects a coin-sized plug of skin, and the animal darts away, startled but uninjured. It is a small act of science with large consequences: that sample will join a decade of biopsies helping researchers understand one of the ocean's most imperilled predators. Globally, the scalloped hammerhead has declined by at least 80%, a collapse driven almost entirely by overfishing and the trade in shark fins.
The species is now classified as critically endangered on the IUCN Red List. Yet the waters around Darwin and Wolf tell a contradictory story. During the cold season, when upwelling currents push nutrients toward the surface, the local population quadruples. At peak density, roughly 150 sharks crowd every hectare of sea — an area no larger than London's Trafalgar Square — so many that their silhouettes can block out the sunlight filtering from above.
That abundance does not make research straightforward.