Billions (10 square miles) of Jelly Fish destroy salmon farm.

10 square miles and 35 feet deep thick of Mauve stinger jellyfish overwhelmed 100,000 salmon at Northern Ireland's only farm. They say it is a disaster and the jelly fish are normally found in Mediterranean.

Managing director John Russell said the company's dozen workers tried to rescue the salmon, but their three boats struggled for hours to push their way through the mass of jellyfish. All the fish were dead or dying from stings and stress by the time the boats reached the pens, he said.

Source

This is an incredible story, from the OP:

Russell, who previously worked at Scottish salmon farms and took the Northern Ireland job just three days before the attack, said he had never seen anything like it in 30 years in the business.

"It was unprecedented, absolutely amazing. The sea was red with these jellyfish and there was nothing we could do about it, absolutely nothing," he said.