A new paper (note) by Stringell, et al. (2015) has documented the first evidence of grey seals feeding on harbour porpoise in UK waters. Supplemental information to the paper includes videos of the observations.

Stringell et al., video 1 porpoise predation from Aquatic Mammals on Vimeo.

Stringell et al. video 2 porpoise predation from Aquatic Mammals on Vimeo.

The lead author of the paper, Tom Stringell , a Senior Marine Mammal Ecologist at Natural Resources Wales said: “With reports of grey seals feeding on harbour porpoises off the coast of Belgium, France and the Netherlands in the past, we were surprised to see this behaviour here in Wales.” “We observed this happening on four separate occasions off the coast of Pembrokeshire. But, it is unclear how long this has been going on for, and why.”

A paper published late in 2014 used genetic studies to find grey seal DNA in bite marks on porpoise carcasses off the Netherlands coast.

### UPDATE ###
Natural Resources Wales have issued the following tweet to reassure the public: