Beach users are being urged to report jellyfish finds on beaches, including the Lion’s Mane which has the most painful sting in the UK and is rarely seen south of Northumberland.
The Marine Conservation Society (MCS), the UK’s leading marine charity, says the number of jellyfish blooms – when jellies mass together – in UK coastal waters is on the increase as our seas start to warm up.
Every summer hundreds of reports of jellyfish sightings are made to the MCS National Jellyfish Survey – now in its 14th year. The survey is providing valuable information about where and when jellyfish occur in UK seas amid global reports of a rise in jellyfish numbers.
Jellies to look out for in UK waters include the Lion’s Mane (Cyanea capillata), which has the most powerful and painful sting of the UK species. It blooms during the summer but is rarely seen south of the Irish Sea, or south of Northumberland, with most reports coming from Scottish waters.
According to the MCS, Lion’s Mane have been spotted in Northumberland in July, as well as in Aberdeenshire, Hebrides, Orkney, Angus and Ceredigion.
Up until July, it’s been a relatively quiet year for jellyfish reports, unlike the last two years when record numbers of barrel jellyfish were reported around UK seas through the spring and summer.
But jellies are starting to pick up as the waters around the UK warm up, with mass strandings of both species in South West England and Wales.
Dr Peter Richardson, Head of Biodiversity and Fisheries at the MCS, said “There’s evidence that jellyfish numbers are increasing in some parts of the world, including UK seas.
“Some scientists argue that jellyfish numbers increase and then decrease normally every 20 years or so, however, others believe and these increases are linked to factors such as pollution, over-fishing and possibly climate change. The MCS jellyfish survey helps provide some of the information we need to understand more about these ancient creatures.
“We still know relatively little about jellyfish and what drives changes in their numbers, so reporting even a single one can help. One thing we do know is that Leatherback turtles travel to UK waters to feed on jellyfish and are usually recorded along the west coast of the UK between May and October – this year we’ve already heard of sightings from the south west of England and the Irish Sea.”
MCS says that anyone who comes across a jellyfish at sea or on the beach should look but don’t touch, but report their sightings via the MCS website.
Jellies to look out for in UK waters:
Moon (very mild sting) – most widespread species, occurring all around the UK coast from May.
Blue (mild sting) – less common than the moon but can turn up anywhere.
Barrel (very mild sting) – can grow up to 1 metre in diameter and weigh up to 40kgs, totally harmless despite its size and is largely limited to the Irish Sea and adjacent waters to the north. Can be spotted all year round, even in winter, but blooms tend to start in March.
Lion’s Mane (powerful sting) – has the most powerful and painful sting of the UK species. It blooms during the summer but is rarely seen south of the Irish Sea (west coast), or south of Northumberland (east coast), with most reports coming from Scottish waters.
Compass (mild sting) – has bizarre compass-like markings and is found throughout the UK coast.
Mauve Stingers (powerful sting) – occasionally recorded from the southwest in early spring, but large numbers were reported off Britain’s west coast during November 2007, 2008 & 2009.
Portuguese Man-of-War (dangerous sting) – rare in UK waters but MCS received many reports from beaches in south-west England in the summers of 2007, 2008 and 2009.