A call has gone out to beachcombers, fish farmers, boatmen and anyone else on Scotland's coast to prepare for the invasion of the jellyfish.

Last week huge numbers of the stinging baby jellyfish choked Northern Ireland's only fish farm off County Antrim, killing 100,000 fish and causing £1m of damage.

The invaders are swarming in Scottish waters and yesterday the Marine Conservation Society (MCS) launched a recruitment drive for volunteer sentries on our beaches to maintain a lookout.

They are to report any sighting of the creatures as part of a national surveillance operation, the MCS Jellyfish Survey.

This month MCS has received reports of millions of baby mauve stinger and compass jellyfish off Skye, the Isle of Eigg, as well as off Ullapool and Durness in Sutherland.

"It is quite unusual for this number of juvenile jellyfish to be occurring in UK waters at this time of year," said Anne Saunders, MCS Scottish projects officer. "But these blooms are phenomenal and consist of millions of individuals, being washed here by strong Atlantic currents."

While compass jellyfish are common throughout UK waters in the summer, mauve stingers are uncommon and are usually only occasionally recorded in the south-west. Both mauve stingers and compass jellyfish can sting. In recent years the mauve stinger has bloomed in the Mediterranean, presenting a bathing hazard to holidaymakers.

The latest reports of an invasion came from Durness in the north-west of Sutherland last week, when a Highland Council ranger reported thousands of compass jellyfish (Chrysaora hysoscella) washing ashore on Balnakeil Beach.

Earlier this month, MCS received reports of huge blooms of baby mauve stingers (Pelagia noctiluca) off Skye, followed by reports of mass compass jellyfish strandings on the Isle of Eigg.

MCS is asking Scottish fish farmers to be vigilant.

Ms Saunders said: "We are urging fish farmers to report any jellyfish blooms they encounter to MCS, through our Fish Farmers Wildlife Reporting Scheme.

Jellyfish swarms can impact on fish and shellfish farms, and while the conditions causing these events remain unclear, such swarms may become more prevalent in Scottish waters as a result of climate change."

More than 4500 jellyfish encounters have been reported since the MCS Jellyfish Survey was launched in 2003.

MCS ask that survey participants do not touch jellyfish as some species can sting. The full-colour MCS jellyfish photo-ID guide can be downloaded from the MCS's website where jellyfish encounters can be reported online.



Most common UK species

The moon jellyfish
(Aurelia aurita)
The most widespread species, occurring from May, as does the less common Cyanea lamarckii.



Barrel jellyfish
(Rhizostoma octopus)
This harmless giant can weigh up to 40kg.



The Lion's Mane jellyfish
(Cyanea capillata)
Has the most powerful and painful sting of the UK species. It blooms during the summer, mostly in Scottish waters.



The Compass jellyfish
(Chrysaora hysoscella)

With its bizarre markings, MCS received several records of large numbers off southwest England.



Mauve stingers
(Pelagia noctiluca)
Recorded from the south-west in early spring.