In 1995 marine scientists from NIWA and the Department of Conservation tagged 95 great white sharks in the waters around Stewart Island and the Chathams.
NIWA scientist Malcolm Francis tagging white shark with acoustic tag. Photo: Warrick Lyon/NIWA.
Since then they've tracked their migration patterns, how far they travelled and why. They found most migrate to the tropics during the winter months - travelling about 100 kilometres a day.
Tracks of three SPOT-tagged white sharks tagged at Stewart Island. Coloured dots are average daily positions (long gaps between dots indicate one or more days without satellite fixes). Blue line = 1,000 m depth contour. NIWA/DOC.
The researchers, Dr Malcolm Francis of NIWA, and Clinton Duffy of DOC, also found the sharks migrate in a straight line, but haven't yet worked out why.
Dr Malcolm Francis explains the findings to Lynn Freeman on Nine to Noon.
