Translocation of Hawaiian monk seals in the Hawaiian Archipelago and Johnston Atoll, USA

Summary

The Hawaiian monk seal (Monachus schauinslandi), Critically Endangered with roughly 1,200 individuals declining about 3% annually, has been managed through translocation across the Hawaiian Archipelago and occasionally to remote Johnston Atoll for three decades, moving 259 seals between 1984 and 2009 to reduce immediate mortality risks such as shark predation and aggressive male conspecifics, shift animals from declining Northwestern Hawaiian Islands subpopulations to the comparatively thriving Main Hawaiian Islands, and address dangerous or unwanted seal-human interactions. Most seals were hard released directly onto beaches, though six weaned pups underwent a soft release with weeks of shoreline-pen acclimation in 1990-1991, and transport ranged from hand-carrying and small boats to large vessels and aircraft; disease screening for cross-subpopulation moves became standard only after the 2000s, though genetic research later confirmed the species is a single panmictic population with no genetic risk from mixing. Post-release monitoring via tags and photo-identification found translocated seals' survival rates statistically indistinguishable from native comparison seals, with weaned pups showing especially high site fidelity and similar foraging behavior to non-translocated pups; only 3 of 259 seals (1.2%) died during the process itself. Difficulties included repeated failures of translocations meant to curb people-habituated seals' human contact, several adult males released at Johnston Atoll disappearing or apparently dying soon after release, and inconsistent post-release monitoring for earlier and more recent cohorts. The project rates itself successful, crediting the species' physical robustness under handling and strict cautious capture and transport protocols.