Shark sets deep dive record

A great white shark tagged by Niwa has set a world record for the deepest known dive at 1200m.

Niwa principal scientist Malcolm Francis said the shark, named "Shack", was the biggest they had tagged at 4.8m.

He said the deepest dives previously seen were about 1000m, "so it's quite a substantial extension".

New Zealand scientists have tagged 25 great whites around Stewart and Chatham Islands over the past five years. The tags are designed to stay on for six to nine months before popping off, floating to the surface and setting off a tracking signal.

Once picked up they offer data on the sharks' movements, having recorded location depth and temperature.

"Before we started this work, it was thought that great white sharks were cold water animals. But it seems they are taking tropical winter holidays, departing New Zealand between April and September for somewhere warmer," Dr Francis said.

"The maximum distance migrated was 300km. One shark returned to its Chatham Islands tagging site after spending six months at Norfolk Island.

"Our sharks don't cross the equator.

"They take long migratory trips making deep dives as they go. They can travel 150km in a day and it takes them just three weeks to get to Australia."

The research aims to improve understanding of the sharks' habits and could help prevent them being accidentally killed by the fishing industry.

- NZPA