An endangered basking shark showed up off North America three years after it was tagged in Ireland, according to new research published by Irish and Canadian scientists.
A female basking shark which was fitted with a satellite transmitter at Malin Head off north Donegal was photographed off the coast of Cape Cod all of 993 days later.
The study by researchers at Queen’s University Belfast (QUB) and Western University, Canada notes this is only the second time that transatlantic movement for the world’s second-biggest fish has been documented.
Basking shark were once hunted off the Mayo coast for their oil, and are now an endangered species risking extinction.
Lead author of the study, QUB PhD student Emmett Johnston has already recorded basking sharks engaged in “bursting” or breaching from the sea of Donegal, and counted some 600 such attempts over a 90-hour period.
"This new evidence offers invaluable information to help us better understand the movements of this endangered species"
The new study, published in the Journal of Fish Biology, noted that the last recorded evidence for transatlantic movement was gathered in 2008 when a female basking shark tagged with a tracking device moved from the Irish Sea to continental waters off the coast of Newfoundland.
“Over 1500 individual sharks have been equipped with either visual identification or satellite tags in the Atlantic to date, leading to just a single record of transoceanic movement, until now,” Mr Johnston said.
“This new evidence offers invaluable information to help us better understand the movements of this endangered species within an international context,” he said.
QUB senior lecturer Dr Jonathon Houghton noted that “for this animal to show up across the ocean three years after it was tagged in Ireland highlights that we really need an international mindset when seeking to conserve this species.”
Co-author of the new study Paul Mensink from Western University said that “in the era of big data”, it was “amazing how much these fortuitous re-sightings of individual animals can tell us about an entire species”.