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.

Earlier this week it was revealed the invaders had choked Northern Ireland's only fish farm, killing 100,000 fish and causing £1 million of damage.

Today it was reported around 140,000 young salmon have been killed north of Belfast and around 15 miles from a the first incident.

Now huge numbers of the stinging baby jellyfish 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 amy sighting of these unseasonal blooms as part of a national surveillance operation, the MCS Jellyfish Survey.

This month MCS has already received reports of millions of baby mauve stinger and compass jellyfish occurring 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 during the summer, mauve stingers are relatively uncommon and are usually only occasionally recorded in the southwest. Both can sting.

In recent years the mauve stinger has bloomed in vast numbers in the Mediterranean, presenting a significant bathing hazard to holidaymakers.

The latest reports of the jellyfish 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 after gale force winds.

Before that, MCS received reports of huge blooms of baby mauve stingers (Pelagia noctiluca) off Skye in early November, followed by reports of mass compass jellyfish strandings on the Isle of Eigg.

Last week a fisherman reported more huge blooms of small mauve stingers in Ullapool harbour and around the nearby Summer Isles.

Similarly large swarms of juvenile mauve stinger jellyfish have been recorded off the coasts of Ireland and Northern Ireland since the end of October, and eventually they mounted their attack on the Antrim coast fish farm.

MCS is asking Scottish fish farmers in particular 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 current events remain unclear, such swarms may become more prevalent in Scottish waters as a result of climate change.

"Therefore, the MCS Jellyfish Survey could prove to be a useful tool in monitoring this situation."

Over 4,500 jellyfish encounters have been reported since the MCS Jellyfish Survey was launched in 2003. The survey data will be fully analysednext year in collaboration with the University of Exeter's Centre for Ecology & Conservation, but initial analysis of these public reports is already showing interesting differences in the distribution of the six larger jellyfish species around Britain.

MCS recommends that survey participants do not touch any jellyfish they encounter as some species can inflict a painful sting.

The full-colour MCS jellyfish photo-ID guide can be downloaded from the MCS's website where jellyfish encounters can be reported online.