A salmon farm was wiped out last week, by a jellyfish swarm that stung and suffocated salmon in a cage. Now a second swarm is floating off the UK shore. It's Frank Schatzing's Swarm.
These "purple stinger" jellyfish are known from waters further south, but their appearance in a mass off the UK is a big surprise in the cold water of November. And nobody expected a killer swarm that could devastate a salmon farm.
One thing that gives jellyfish a boost is the removal of fish due to overfishing, so we may see more of this in the future if we don't stop overfishing our oceans.