Data from: Fear dynamically structures the ocean's pelagic zone

Fear of predation can have wide-ranging ecological effects.This is
especially true in the ocean’s pelagic zone, the Earth’s largest habitat,
where vertical gradients in light and primary productivity force numerous
taxa to migrate vertically each night to feed at the surface while
minimizing risk from visual predators. Despite its importance, and the
fact that it is driven by spatial differences in perceived risk, diel
vertical migration (DVM) is rarely considered within the “landscape of
fear” framework. It is also far from the only such process in the pelagic
zone. We used continuous, year-long records from an upward-looking
echosounder and broadband hydrophone at a cabled observatory off Central
California, USA, to observe avoidance reactions by several groups of
pelagic animals to the presence of their predators. As expected, vertical
migration was ubiquitous, but we also observed behaviors at shorter and
longer time-scales which were best explained by fear of predation. The
presence of foraging odontocetes induced immediate diving behavior in
mesopelagic sound-scattering layers, and schools of epipelagic fishes
induced similar behaviors in layers of zooplankton and mesopelagic
micronekton. At longer time scales, the presence of fish schools
significantly deepened vertical migration, rearranging life throughout the
water column. We argue that behavioral reactions to predation risk are
common in the pelagic zone at a range of spatiotemporal scales and that
our understanding of food webs and biogeochemical cycling in this immense
biome will be incomplete unless we account for fear.