People living in a town in Cornwall have been left baffled after a video emerged showing hundreds of small fish dead on a popular beach.
Footage shared on Facebook shows the fish - believed to be mackerel or sardines - lay dead on Porthgwidden Beach in St Ives, but the cause of the mass stranding is not known.
A person suggested the fish may have died due to sewage being pumped into British coastlines.
Another said the fish could have been pushed ashore by dolphins, following several sights around Cornwall.
The clip was published on the Facebook page for a gift shop in Topsham, Exeter, called 'The Day That...' and the store owner Tom Freeland said he has never seen anything similar.
He said: "I haven't seen anything like that before, but I've seen mackerel come in very close to the shore around Devon.
"The likely suggestions, given how many dolphins there have been around recently and even a humpback whale, is they got chased into shore by a hungry pod of dolphins.
"I think, because of the water quality around here, it would be quite obvious if suddenly a load of sewage was dumped in. There's not been any rain recently so it's unlikely there would be a sewage dump."
A similar incident happened in 2018 when hundreds of fish were stranded on Gwithian beach, near Hayle, as well as on Porthgwidden Beach.
Dog walker Jill Clark told Cornwall Live: "There were hundreds of fish which looked like they had got stranded in one of the many pools there when the tide went out.
"They were alive and thrashing around. Never seen this before. It was upsetting but there was nothing we could do."
The RSPCA previously said the stranding of mackerel in Cornwall was extremely unusual.
It is believed the fish were caught out by the changing tide after finding themselves trapped in the shallows beside the stone steps leading down from Wharf Road in St Ives.
A spokesperson for the RSPCA said: "In terms of how commonly this occurs, according to our wildlife scientist in our headquarters, this is relatively unusual although incidents seem to occur sporadically around the coast."
Following a similar incident on Hove beach in 2019, the morning officer from the Brighton Seafront Team said fish are sometimes pushed ashore after being chased by sea bass, the odd seal or dolphin.
He said: "What you have is whitebait that are being corralling by mackerel, you can see the large movement in the water.
"They push the whitebait towards the shore - and these mackerel are sometimes chased by sea bass and sometimes the odd seal or dolphin.
"Once they are towards the shore, you can get a wave surge which leaves a large number of fish deposited on the beach.
"They then try to flip themselves back into the water - but some do not make it and others are picked up by the seagulls."
