Scientists at the National Institute of Water and Atmospheric Research are astonished at the migratory pattern of a mako shark they are tracking.
Mako are targeted for their fins and flesh and the study will be used to set quota for fishing them.
The shark the scientists are tracking, Carol, is fitted with an electronic tag that emits a signal each time her dorsal fin breaks the surface of the water.
NIWA scientists knew mako headed to Fiji for winter, but Carol surprised them by swimming halfway to Fiji, then returned abruptly to New Zealand before swimming all the way to Fiji again.
She then returned to New Zealand after a few weeks.