2008 Report: An Extraordinary Journey

Even before the basking shark season has begun in the UK, the project has already had some amazing results from the two tags deployed in 2007 off the Isle of Man, with one of the sharks moving north from the Isle of Man into the Clyde Sea Area, rather than continuing further north to the Hebrides.

It was the other individual however, who produced something quite extraordinary. The tagged female travelled 9,589 km to the waters off the Newfoundland shelf, and on her journey across the Atlantic Ocean managed to reach a maximum depth of 1,264 metres.

This data not only provides the deepest recorded dive depth for any tagged shark, but shows the first evidence for basking sharks utilising the deep mid-ocean and more significantly still, that the species is able to migrate across oceans or even hemispheres. This individual’s journey gives us the first tangible evidence that the European and American populations could be considered a single reproductive pool; previous to this they were always assumed to be discrete populations.

The implications from a conservation standpoint are also significant. Though basking sharks are protected in European waters, if as we now know, they are able to traverse from ocean to ocean, they could well travel into water where they have no protection. This research highlights the need for international collaboration with both governments and scientists if this vulnerable species is to have a chance of surviving.