Acoustic receivers have proven great white sharks from Stewart Island have been visiting Australia and New Caledonia, taking as little as 21 days to cross the Tasman for their winter break.
Australian scientists recently recorded on their receivers a New Zealand great white shark, tagged by Niwa and Department of Conservation (Doc) staff at Stewart Island in March 2011.
"In February 2012, a 2.8m-long shark known as Meadsy was picked up on a receiver 10km off Bondi Beach," Niwa principal scientist Dr Malcolm Francis said.
"It was picked up again at Stewart Island in March 2012 by our receiver array, having crossed the Tasman Sea in 21 days at an average speed of 96km per day."
The scientists recently downloaded data from acoustic receivers deployed off the east coast of Australia and in the Coral Sea.
An unnamed great white male shark, 3.3m long, was tagged at Stewart Island in March 2011 and then detected at Chesterfield Reefs in October 2011.
"Ella, a 4.4m-long great white shark was tracked from Stewart Island to New Caledonia in both 2009 and 2011," Dr Francis said.
Another big great white shark, Phred, who is 4.8m long, was also tracked to Chesterfield Reefs in the Coral Sea in 2009.
This year scientists tagged 20 great white sharks with acoustic tags and five with pop up tags near the Titi (Muttonbird) Islands off the northeast coast of Stewart Island. In 2011, they tagged 25 in the same area.
A recent download of the Stewart Island receivers has provided a second year of data on the local movements, times of departure, and arrival of great white sharks in the area, he said.
"Many of the same white sharks are seen every year at Stewart Island, indicating an amazing ability to navigate back to the same spot after travelling thousands of kilometres across open ocean."
Researchers also want to find out when the sharks inhabit "hotspot" locations such as Stewart Island, and the size of the New Zealand population of great whites.
Doc scientist Clinton Duffy said they also recently tagged a mako shark, Carol, who is 1.8m long, with a satellite-transmitting tag on her dorsal fin.
"Carol was tagged in May 2012, at the Bay of Islands, and she headed off halfway towards Fiji. She then came back to Ninety Mile Beach, in Northland, where she spent six weeks, and then set off for Fiji again."
She arrived off the Yasawa Islands last week, having travelled 1900km in 28 days.
Carol has swum nearly 6400km in 111 days.
