Diverse habitats shape the movement ecology of a top marine predator,
the white shark Carcharodon carcharias
Abstract
An animal’s movement is influenced by a plethora of internal and
external factors, leading to individual- and habitat-specific movement
characteristics. This plasticity is thought to allow individuals to
exploit diverse environments efficiently. We tested if the movement
characteristics of white sharks Carcharodon carcharias differ across
ontogeny and among habitats along the coast of Central California. In
doing so, we elucidate how changes in internal state (physiological
changes coinciding with body size) and external environments (differing
seascapes and/or diel phases) shape the movement of this globally
distributed predator. White sharks, from small juveniles to large
adults, were equipped with motion-sensitive biologging tags at four
contrasting seascapes: two islands, a headland, and an inshore cove.
From multi-sensor biologging data, 20 metrics characterising movement
were derived and subjected to multivariate analyses. Movement
characteristics were most different across seascapes, followed by
ontogeny and diel phase. Juvenile sharks, that were only encountered at
the cove, displayed the most distinct movement characteristics. Sharks
at this seascape remained close to the shore and were comparatively less
active than sub-adult and adult sharks tagged elsewhere. Distinct
night-time movements and dive patterns were recorded from sharks at an
island seascape but not from those at the headland or inshore cove. The
availability of prey and access to deeper water are likely drivers, with
greater numbers of Northern elephant seals Mirounga angustirostris at
the island seascapes and harbour seals Phoca vitulina at the headland
seascape, while the offshore island group is also closer to the
continental shelf edge. Juvenile sharks at the inshore cove are
piscivorous and their habitat was not adjacent to pinniped haul out
areas nor deeper water. This study demonstrates plasticity in the
movements of a top predator, that adapts its routine to suit the habitat
it forages within.