Study’s new depth to sharks
GREAT white sharks sink as deep as 108 metres into the ocean and swim back to the surface to save energy when hunting for seals, according to a study by Australian and international researchers.
These “behavioural strategies” help sharks to maximise their energy and allow them to increase encounter rates with fast-swimming seals, according
to the study published in The Company of Biologists
journal. The study said the method was similar to “sitting and waiting” for prey to approach them, rather than swimming long distances fast to hunt. The sharks exhibited a series of energy-efficient gliding behaviours during descending phases of dives followed by active ascents.
The behaviour is more efficient than horizontal surface swimming, which requires more energy, the study says.
The study was conducted by attaching accelerometers and video cameras to 10 great white sharks to see how they used energy when hunting for long-nosed fur seals off the Neptune Islands, South Australia.