Large numbers of potentially fatal Portuguese man-of-war prompted the closure of a Cornish beach.
RNLI lifeguards closed Perranporth beach when they found “an unusually large number” of the man-of-war.
The jellyfish-like creatures with long purple tentacles have been seen in Cornwall and Wales this month says the Marine Conservation Society (MCS).
And with sea temperatures around 16C, there are concerns about swimmers getting stung.
RNLI manager Dickon Berryman told the BBC Perranporth beach was closed “for a short time” while lifeguards took advice on the level of danger to beachgoers.
The beach has since reopened.
Man-of-war were spotted at Newgale, Pembrokeshire, on 8 September and the next day on beaches around holiday destination Newquay.
They have also been seen at Porthmelon Beach on the Isles of Scilly and on the Cornish beaches of Portheras Cove and Summerleaze, Widemouth, Perranporth, Hayle, Holywell Bay and Praa Sands. Six were reported at Gwithian.
Dr Peter Richardson from the MCS said a man-of-war’s tentacles which are about 10m (30ft) long, “deliver an agonising and potentially lethal sting”.
“They are very pretty and look like partially deflated balloons with ribbons but picking one up could be very nasty,” he said.
The man-of-war retain their sting when they are wet, even if they look dead, he warned.
He advised anyone who was stung to get the tentacles away from the body as soon as possible.
Leatherback turtles have also been washed up because of an increase in jellyfish which they feed on, Dr Richardson said.
A leatherback turtle was found at Portreath on 9 September and another one has been reported in Pembrokeshire.
If symptoms become more severe, or a sensitive part of the body has been stung, you should seek medical help.
The MCS is asking people to report any sightings which could rise as man-of-war are driven across the Atlantic by recent storms.