Salmon farms braced for jellyfish invasion

SCOTLAND'S salmon producers have been put on alert due to an invasion of stinging jellyfish which have already wiped out a fish farm in the Irish Sea.

Fears have been raised after swarms of the alien creatures, normally found in the Mediterranean, were spotted off the west coast, with some stranded on beaches.

Just a few centimetres long and relatively harmless in small numbers, the jellyfish can be deadly when amassed in such vast quantities.

The Marine Conservation Society (MCS) said it has received reports this month of millions of baby mauve stinger and compass jellyfish being seen in "blooms" off Skye, Eigg, Ullapool and in the sea near Durness in the far north of Sutherland.

Mauve stingers were the species which last week killed 100,000 salmon worth over £1 million at Glenarm Bay and Red Bay, Cushendun, off the Co Antrim coast, site of Northern Ireland's only salmon farm.

They attacked by stinging and then stressing the salmon, which were in cages about a mile into the Irish Sea. The attack lasted seven hours, with the jellyfish covering an estimated sea area of ten square miles and 35ft deep.

With the potential threat to Scottish fish farms, the Scottish Salmon Producers' Organisation (SSPO) has warned its members to be on their guard.

As well as using their sting, jellyfish can kill caged fish by using up oxygen in the water or, if small enough, getting into their gills to suffocate them.

A SSPO spokesman said: "Dealing with the presence of jellyfish is a feature of working in the marine environment. However there appears to have been very little that the farmers in Northern Ireland could have done to prevent this from having the devastating impact it has. The scale of attack is unprecedented - reports have suggested there were billions of jellyfish.

"Farmers in Scotland have been made aware of the size of the invasion and will remain vigilant over the coming days."

The MCS has also warned fish farmers to be aware of the hazard. It wants them, as well as people on beaches, sailors and surfers, to report sightings of the jellyfish as part of a national survey.

Anne Saunders, the MCS Scottish projects officer, said that while compass jellyfish were common throughout UK waters during the summer, mauve stingers were relatively rare and usually only occasionally recorded in the south-west.

"It is quite unusual for this number of juvenile jellyfish to be occurring in UK waters at this time of year," she added. "But these blooms are phenomenal and consist of millions of individuals. They are being washed here by strong Atlantic currents, which bring them much further north than usual and that's why they are turning up off Scotland and Ireland."

The latest reports of the jellyfish invasion came from Durness last week, when a council ranger reported thousands of compass jellyfish washing on to the shore at Balnakeil beach.

Before that, MCS received reports of huge blooms of baby mauve stingers off Skye early this month, and of mass compass jellyfish strandings on Eigg.

A fisherman reported huge blooms of small mauve stingers in Ullapool harbour last week.

Ms Saunders warned people not to touch jellyfish in case they are stung. So far over 4,500 jellyfish "encounters" have been reported since the MCS survey was launched in 2003.