While walking on Ninety Mile Beach in the far north of New Zealand recently Clare Veltman spotted an object on the sand shaped like a large fishing lure with an antenna. The tag, used by scientists to track sharks, included the manufacturer’s details and a serial number.
“I knew what it was so I put it in my pack and decided to do something about it once I got to Kaitaia,” Clare said.
The study is trying to determine whether the way sharks are caught and released makes a difference to their survival.
“This is the first tag out of 75 that have been deployed that has been returned to us since the study began in May last year,” said NIWA shark researcher Warrick Lyon. “It provides us with really detailed information that we wouldn’t otherwise have.”
The tag was deployed on a 2.5m mako shark by a fisheries observer aboard a tuna longline vessel working off New Caledonia on July 3. The shark was then released, and swam to New Zealand.
A steel pin in the tag is designed to corrode after 60 days, allowing it to float to the surface from where it starts broadcasting data to a satellite system.
“The information we get from the tags includes a daily report of minimum and maximum water temperatures, and maximum depth of the shark while the tag was attached.
If we get the tag back, we can retrieve much higher resolution data at ten minute intervals. That level of detail is far more valuable and very exciting.”
There is a $200 reward for the return of the tags which Clare Veltman used to upgrade her sleeping mat for her trekking. Mr Lyon says there is at least one tag somewhere at Lottin Point, Cape Runaway waiting to be found.