Huge jellyfish lured to UK beaches by warm seas

Jellyfish measuring up to half a metre in length have been appearing on beaches in Scotland, following a rise in sea temperatures.

People on the beaches around Banff in the Moray Firth, north of Aberdeen, have been warned to look out for giant stinging jellyfish which have been washed up in their thousands over the summer.

"It's very rare to see 40cm-plus common jellyfish but the waters have been full of them over the past few weeks," said Dr Kevin Robertson, of Scotland's Cetacean Research and Rescue Unit. "The temperatures are very much higher in the coastal waters this year. Normally at this time of year we measure maximum temperatures of about 14 or maybe 15 degrees, but we are well into higher figures at the moment – around 17 degrees at least.

"It's created ideal conditions for a jellyfish boom and we are seeing much larger specimens than usual as they fulfil their full growth potential."

Moon jellyfish, which are by far the most common in the area, usually grow to just 10cm.The hot summer weather has also fuelled the growth of the lion's mane jellyfish, the largest to visit UK shores. Some specimens measure more than a metre in diameter.

The tentacles of the lion's mane jellyfish, which is easily identified by its ragged edges, carry a nasty sting which can leave unsuspecting swimmers in pain for hours.

Increasing numbers of jellyfish are currently being sighted across the UK, with the Marine Conservation Society (MCS) calling on visitors to the British seaside to report their observations.

"This year's jellyfish season started in earnest in April in the Irish Sea, when barrel and moon jellyfish were reported off the Welsh coast," said Peter Richardson, biodiversity programme manager with the MCS.

"Through May and June, barrel and moon jellyfish reports increased, with moon jellyfish reports coming from elsewhere along with reports of other species such as the beautiful blue and compass jellyfishes.

"We started receiving reports of stranded lion's mane jellyfish off Wales and Northern Ireland in June. We are encouraging holidaymakers to take part in our national jellyfish survey, but the key message is look – don't touch."