Oceanic Spawning Migration of the

European eels (Anguilla anguilla) under-take a ~5000-km spawning migration fromEurope to the Sargasso Sea (1), although details of the migration remain unknown. Satellite tracking enables investigation of migratory be-havior of large ocean-dwelling animals (2), but tag sizes have precluded tracking smaller animals like European eels. Here, we present information about the spawning migration of European eels based on a miniaturized pop-up satellite archival transmitter (PSAT). The experiment fell short of revealing the full migration to the Sargasso Sea, but the tags tracked eels up to 1300 km from release and provided unique behavioral insights. Transmissions were received from 14 of 22 tagged silver eels released on the west coast o