Jellyfish 'the size of dustbin lids' spotted in Cornwall
30 June 2014 Last updated at 08:15 BST
Barrel jellyfish "the size of dustbin lids" have been spotted along the south coast of England, from Cornwall to Dorset.
They have not been seen in such numbers in the area since 2002.
Marine biologist Matt Slater of the Cornwall Wildlife Trust spoke to the BBC's David George about their appearance.