Basking sharks, hundreds of which are found off the shores of Ireland, Cornwall, the Isle of Man and Scotland and the second largest fish in the world reaching lengths up to 10m (33ft), have previously had a reputation for being slow and languid as they scour the sea for their staple diet of plankton.

However, a new study recently published in the Journal Biology Letters used video analysis for both species to estimate vertical swimming speeds at the moment of leaving the water. Furthermore, they instrumented one large basking shark with a data recording device to measure speed, movement and  also to store video footage. 

At one point during deployment of the recording device, in just over nine seconds and 10 tail beats, the basking shark accelerated from a depth of 28 m to the surface, breaking through the water at nearly 90 degrees. The shark cleared the water for one second and peaked at a height of 1.2 m above the surface.

To achieve this breach, the basking shark exhibited a six fold increase in tail beat frequency and attained a top speed of approx. 5.1 m/s. This is more than twice as fast as the average competitor in the Olympic men’s 50m freestyle swim.

The videos from boats and the land of both basking sharks and great whites breaching showed similar speeds of breaching in other individuals. The basking shark videos were recorded in 2015 at Malin Head, Ireland, while the great white shark videos were recorded in 2009 at two sites in South Africa, where seal-shaped decoys induced feeding attempts.

Dr Jonathan Houghton, Senior Lecturer in Marine Biology from the School of Biological Sciences  and the Institute for Global Food Security at Queen’s commented: “This finding does not mean that basking sharks are secretly fierce predators tearing around at high speed; they are still gentle giants munching away happily on zooplankton.

"It simply shows there is far more to these sharks than the huge swimming sieves we are so familiar with. It’s a bit like discovering cows are as fast as wolves (when you’re not looking)."

Dr Nick Payne, Assistant Professor in Zoology at Trinity College Dublin and co-author on the research said: “The impressive turn of speed that we found basking sharks exhibit shows how much we are yet to learn about marine animals – even the largest, most conspicuous species have surprises in store, if we're willing to look.”

The collaborative research team comprised of biologists from Queen’s University Belfast, University of Roehampton, Trinity College Dublin, University of Cape Town, Irish Basking Shark Study Group and the South African Institute for Aquatic Biodiversity.