The mako shark, with GPS tag attached.
Credit: Scott Tindale
A mako shark fitted with a GPS tag six months ago in the waters off New Zealand has already traveled a whopping 8,265 miles (13,300 kilometers), a distance that came as quite a surprise to scientists, according to the New Zealand Herald.
The shark, nicknamed Carol, is a shortfin mako, the world's fastest shark, according to a release from New Zealand's National Institute of Water and Atmospheric (NIWA) Research, which helped fund the tracking project.
This is the first time that researchers have tracked a shortfin mako in real-time, scientist and project leader Malcolm Francis said in the statement. Nevertheless, scientists didn't expect to see such erratic movement.
"What really surprised us was Carol took off to Fiji once, got about halfway there and turned around and came straight back to New Zealand … for about six weeks, and then she did go to Fiji," Francis said, according to the New Zealand Herald.
Researchers expected that the shark would stay in Fiji's warm waters once it got there, and only return to New Zealand once summer returned and Kiwi waters heated up. But Carol spent very little time in Fiji before returning to New Zealand. Francis told the Herald that researchers don't know for certain why the shark would spend so little time in Fiji, but speculate that there wasn't enough suitable food in the region at the time.
"One thing about studies like this is we find out all this new information, and we know what they're doing, but why they're doing it we just can't get at," Francis told the Herald.
The tagged shark has traveled an average of 37 miles (60 km) per day over the past six months, sometimes exceeding 62 miles (100 km) in a day's journey. Shortfin mako can travel up to 62 mph in short bursts, according to the NIWA release.
Carol is 6 feet (1.8 m) long, but, in general, shortfin mako can grow up to 13 feet (4 m), according to the International Union for the Conservation of Nature (IUCN). The union considers the species vulnerable on its endangered rating scale. Makos are accidentally caught by fishermen, but also intentionally caught for their fins to be made into shark fin soup, the IUCN says. The sharks' numbers are in decline in many areas throughout the world.