Long-distance movements of a scalloped hammerhead shark connect the Galapagos Islands with coastal areas and international waters of the Tropical Eastern Pacific

Scalloped hammerhead sharks (Sphyrna lewini) are critically endangered, yet we still have a limited understanding of their fine-scale movements across the Tropical Eastern Pacific, a region experiencing high levels of industrial and artisanal fishing. Here, we used closed circuit rebreathers for close approach for in situ tagging to deploy a towed satellite transmitter that track for 204 days the movements of an adult, likely pregnant female shark. Our results provide the longest (5783 km, 28.3 km/day) and most spatially extensive (81.75–109.6 W) satellite track for this species to date. Movements connected the Galapagos Marine Reserve (GMR), the coast of Panama (> 1200 km away and a known birthing area for the species), and an offshore area > 1800 km west of the Galapagos. The long period (~ 77 days) tracked within international waters to the west of the GMR highlights the urgent need for international cooperation to revert ongoing population declines for this iconic species.