Aquaculture: Jellyfish Dominate as Predators Disappear

By Abigail Tucker
Smithsonian Magazine

As the world’s oceans are degraded, will they be dominated by jellyfish? Boneless, bloodless and brainless, they thrive in warming oceans and dead zones, unaffected by CO2, spewing 45,000 eggs a day. A bourgeoning enterprise capitalizes on jelly blooms, as global fisheries collapse from over-harvesting, reports Abigail Tucker.

Northeast Pacific sea nettles. (Image by John Lee)

Jellyfish: The Next King of the Sea

On the night of December 10, 1999, the Philippine island of Luzon, home to the capital, Manila, and some 40 million people, abruptly lost power, sparking fears that a long-rumored military coup d’état was underway. Malls full of Christmas shoppers plunged into darkness. Holiday parties ground to a halt. President Joseph Estrada, meeting with senators at the time, endured a tense ten minutes before a generator restored the lights, while the public remained in the dark until the cause of the crisis was announced, and dealt with, the next day. Disgruntled generals had not engineered the blackout. It was wrought by jellyfish. Some 50 dump trucks’ worth had been sucked into the cooling pipes of a coal-fired power plant, causing a cascading power failure. “Here we are at the dawn of a new millennium, in the age of cyberspace,” fumed an editorial in the Philippine Star, “and we are at the mercy of jellyfish.”

A decade later, the predicament seems only to have worsened. All around the world, jellyfish are behaving badly—reproducing in astonishing numbers and congregating where they’ve supposedly never been seen before. Jellyfish have halted seafloor diamond mining off the coast of Namibia by gumming up sediment-removal systems. Jellies scarf so much food in the Caspian Sea they’re contributing to the commercial extinction of beluga sturgeon—the source of fine caviar. In 2007, mauve stinger jellyfish stung and asphyxiated more than 100,000 farmed salmon off the coast of Ireland as aquaculturists on a boat watched in horror. The jelly swarm reportedly was 35 feet deep and covered ten square miles.

Nightmarish accounts of “Jellyfish Gone Wild,” as a 2008 National Science Foundation report called the phenomenon, stretch from the fjords of Norway to the resorts of Thailand. By clogging cooling equipment, jellies have shut down nuclear power plants in several countries; they partially disabled the aircraft carrier USS Ronald Reagan four years ago. In 2005, jellies struck the Philippines again, this time incapacitating 127 police officers who had waded chest-deep in seawater during a counterterrorism exercise, apparently oblivious to the more imminent threat. (Dozens were hospitalized.) This past fall, a ten-ton fishing trawler off the coast of Japan capsized and sank while hauling in a netful of 450-pound Nomura’s jellies.

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