Massive swarms of jellyfish are a growing threat to swimmers, the fishing industry, and even the nuclear power industry, a new report argues, and it’s high time for scientists to begin researching the causes of the population boom and how to reverse the trend. The new report from the National Science Foundation may tend towards sensationalism (the report is titled “Jellyfish Gone Wild!!“), but the problem is very real. The report says more than 1,000 fist-sized comb jellies can be found in a cubic yard (meter) of Black Sea water during a bloom. They eat the eggs of fish and compete with them for food, wiping out the livelihoods of fishermen, according to the report [Reuters]. A big swarm of jellies can also burst a fishing net or poison and crush a load of captured fish, the report says, and their bodies can clog boat engines.
“When jellyfish populations run wild,” the NSF jellyboffins warn, “they may jam thousands of square miles with their pulsing, gelatinous bodies.” It seems that no less than half a billion “refrigerator sized” slimy horrors weighing 450 pounds each invade the Sea of Japan daily, while Australian waters are plagued with “deadly, peanut-sized” Jellybabies of Death [The Register]. Popular tourist beaches from Spain to Alabama have been closed in recent years when swarms of stinging jellies threatened to harm bathers. As for their impact on nuclear power: The report claims that swarms of jellies sometimes clog the water intake pipes of power plants, and notes that in 1999 just such an incident forced a power plant in the Philippines to shut down, which “plunged 40 million people into darkness and started rumors of a coup d’etat.”
Jellyfish (which are not really fish, as they’re invertebrates) have been called the cockroaches of the sea for their ability to thrive under all sorts of conditions, and the report says their numbers are now booming because they’re able to adapt to a variety of man-made environmental changes. They’re … definitely linked to ocean pollution. There are now oxygen-starved dead zones in the oceans so polluted that jellyfish are the only creatures able to survive. Also, their major natural enemy are sea turtles but all seven sea-turtle species are now indecline and threatened. And warming seas make it easier for the various soft-bodied critters to spread and thrive [ZDNet].
The report comes at the same time as the European Union is reviewing the fish quotas set for commercial fishing operations, a process that has been heavily criticized by scientists and environmentalists who say that high quotas are putting many fish species at risk of extinction. Scientists have said that unless the system is completely overhauled fish stocks will continue to deplete to the point of extinction by 2048, leaving consumers little option but to eat jellyfish or the small bony species left behind at the bottom of the ocean…. “If we do not change our ways we will have less and less to catch… so jelly fish could end up on the menu as opposed to cod in our fish and chips” [Telegraph], said marine conservationist Callum Roberts.
Image: Michael Dawson, University of California, Merced