The footage was recorded by Dan Wise. Copyright the Orkney Skate Trust.
The screenshot (right) shows a close up still of the skate swimming.
More footage of skate underwater can be viewed on the Orkney Skate Trust website here.
Below is a short clip of a female common skate coming to the boat in the Sound of Jura. The fish was caught by Patrick Lawlor, her weight was calculated using SSTP charts at 174lb.