The sharks were spotted in the Cape Cod area and harpoon-tagged with electronic satellite trackers, in what is thought to have been the first such exercise carried out successfully in Atlantic waters.
An attempt to tag a great white off Cape Cod’s Naushon Island in 2004 failed when the tracker detached.
Amazingly, the five recent taggings were achieved in the space of just five days. They come after a period in which sightings of great whites in the area have increased steadily.
It is thought that the sharks have been drawn by a growing seal population. Three – estimated at 4.5m, 3.5m and 3m long – were tagged off Chatham, where hundreds of seals are based on nearby Monomoy island.
The Chatham sharks were spotted just a few hundred metres from the mainland shore, prompting the closure of some beaches to swimmers.
The operations were overseen by Massachusetts State shark researcher Greg Skomal, working with a spotter plane and a fast fishing boat with tag harpoon.
The tags will record water temperatures and depths, before detaching automatically in January and sending their data home via satellite.
Computer programmes will be able to analyse the information to determine where the sharks have travelled.
“While they are such a high-profile species, we know nothing about their migratory patterns and behaviour, at least in the Atlantic Ocean,’’ Kate Plourd, of Massachusetts State Division of Marine Fisheries, told press.
“Being able to study them, and track them, will contribute to the study of the species.’’
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