In November 2009 a net full of gigantic jellyfish, the largest of which weighed over 450 pounds, capsized a Japanese trawler, throwing the three-man crew into the ocean. But even mightier vessels have been vanquished by jellyfish.
On July 27, 2006, the USS Ronald Reagan, then the most modern aircraft carrier in existence, was docked in the port of Brisbane, Australia. New Zealand had earlier banned the entry of nuclear-powered ships, and many Australians felt it might be prudent to follow their lead. So when the commander of US Naval Air Forces announced that an “acute case of fouling” had afflicted the giant vessel, people took notice. Thousands of jellyfish had been sucked into the cooling system of the ship’s nuclear power plant, forcing the closure of full onboard capabilities. Newspapers ran the headline “Jellyfish Take on US Warship.” Local fire crews were placed on standby, and the citizens of Brisbane held their collective breaths as the battle between the navy and the jellyfish raged. In the end, they proved too formidable, and the ship was forced out of port.
Even nations can be affected by the power of the jellies. On the night of December 10, 1999, 40 million Filipinos suffered a sudden power blackout. President Joseph Estrada was unpopular, and many assumed that a coup was underway. Indeed, news reports around the world carried stories of Estrada’s fall. It was twenty-four hours before the real enemy was recognized: jellyfish. Fifty truckloads of the creatures had been sucked into the cooling system of a major coal-fired power plant, forcing an abrupt shutdown.
Japan’s nuclear power plants have been under attack by jellyfish since the 1960s, with up to 150 tons per day having to be removed from the cooling system of just one power plant. Nor has India been immune. At a nuclear power plant near Madras, workers removed and individually counted over four million jellyfish that had become trapped on screens placed over the entrances to cooling pipes between February and April 1989. That’s around eighty tons of jellyfish.
As Gershwin says, “Jellyfish have an uncanny knack for getting stuck…. Imagine a piece of thin, flexible plastic wrapper in a pool, where it can drift almost forever without sinking, until it gets sucked against the outflow mesh.” Chemical repellents don’t work, nor do electric shocks, or bubble curtains, or acoustic deterrents. In fact even killing the jellyfish won’t work as, dead or alive, they still tend to be sucked in. And everyone from concerned admirals to the owners of power plants that lose millions of dollars with each shutdown have tried very hard to deter them.
Salmon swimming in pens can create a vortex that sucks jellyfish in. Tens of thousands of salmon can be stung to death in minutes, and repeated attacks can kill hundreds of thousands of the valuable fish. But those losses are small compared with the financial devastation jellyfish have inflicted elsewhere. Would you believe, Gershwin asks, that “a mucosy little jellyfish, barely bigger than a chicken egg, with no brain, no backbone, and no eyes, could cripple three national economies and wipe out an entire ecosystem”? That’s just what happened when the Mnemiopsis jellyfish (a kind of comb jelly) invaded the Black Sea. The creatures arrived from the east coast of the US in seawater ballast (seawater a ship takes into its hold once it has discharged its cargo to retain its stability), and by the 1980s they were taking over. Prior to their arrival, Bulgaria, Romania, and Georgia had robust fisheries, with anchovies and sturgeon being important resources. As the jellyfish increased, the anchovies and other valuable fish vanished, and along with them went the sturgeon, the long-beloved source of blini toppings.
By 2002 the total weight of Mnemiopsis in the Black Sea had grown so prodigiously that it was estimated to be ten times greater than the weight of all fish caught throughout the entire world in a year. The Black Sea had become effectively jellified. Nobody knows precisely how or why the jellyfish replaced the valuable fish species, but four hypotheses have been put forward.