The Worldwide Slime Smackdown

By Bruce E. Johansen 

Human beings, narcissistic souls that we are, rarely pay much attention to what goes on out of sight—for example, in the two-thirds of the Earth that is covered with salt water. That goes double for many of us who live in the middle of continents, hundreds of miles from the oceans.

Now comes disquieting news from the shore. Jellyfish love warm water, especially polluted water. Human beings who have overpopulated the land are serving jellyfish a dream habitat, and smacks of slime are multiplying rapidly. Our grandchildren may grow old in a time when jellyfish are the oceans’ dominant species. Jellyfish have been called ‘the cockroaches of the open waters.’

On the shores of the Sea of Cortez, in northwestern Mexico, most fish are gone, but ‘cannonball jellies’ have arrived. Former fishermen are loading their boats, salting them, and shipping their new harvest off to China, where, wrote Erik Vance in the August 2013 Harper’s, “They are a bland sort of staple.”

By the summer of 2004, reports indicated that jellyfish populations were on the rise in Puget Sound, the Bering Strait, and the harbors of Tokyo and Boston. ‘Smacks’ or swarms of jellyfish shut down fisheries in Narragansett Bay, parts of the Gulf of Alaska, and sections of the Black Sea. In the Philippines, 50 tons of jellyfish shut down a power plant, provoking blackouts, when they were sucked into its cooling system. During late July, 2003, thousands of barrel jellyfish and moon jellyfish washed up on the coast of southern Wales.

Jellyfish Thrive Worldwide

Near Barcelona, Spain, fishermen found their nets slimed with jellyfish as more than 300 beachgoers per day were treated for stings during the summer of 2008. All over the world, jellyfish have been proliferating as their predators have been over-fished, pollution has depleted oxygen levels, and water temperatures have gradually risen. These problems are especially severe in the landlocked Mediterranean Sea.

During 2008, beaches have closed because of jellyfish swarms at Cote d’Azur in France, the Great Barrier Reef of Australia, and at Waikiki and Virginia Beach in the United States. In Australia, where the deadly Irukandji jellyfish is expanding its range in warming waters, the number of jellyfish stings rose to 30,000 treated cases in 2007, double 2005’s total.

A jellyfish smack 16 kilometers square at a depth of 35 feet late in 2007 invaded the Northern Salmon Company, Northern Ireland’s only salmon farm, killing more than 100,000 fish, at a cost of more than $2 million. Billions of Pelagia nocticula (Mauve Stingers) swarmed into the cages holding the fish about a mile into the Irish Sea, off Glenarm Bay and Cushendun.

EDF Energy’s Torness nuclear power station in Scotland, shut down its two reactors June 28, 2011, after a huge smack of jellyfish clogged the water intakes for its cooling towers.

Jellyfish as Indicators of Stressed Ecosystems

“Jellies are a pretty good group of animals to track coastal ecosystems,” said Monty Graham, a scientist at the University of South Alabama. “When you start to see jellyfish numbers grow and grow, that usually indicates a stressed system.” Those stresses include increased water temperature, a rise in nutrients (from fertilizers and sewage), and depleted stocks of other fish, often caused by over-fishing, which removes the jellyfish’s competitors. All of these changes are usually human-caused, according to Graham.

In 2002, a report appeared in the Boston Globe describing a massive infestation of jellyfish in Narragansett Bay and Long Island Sound. “Eventually it seemed that our deck was coated with vaseline,” said Captain Eric Pfirrmann, who works for “Save The Bay,” a group whose members engage in environmental issues related to Rhode Island’s Narragansett Bay.

The combjelly’s reproductive cycle adjusts to the warmth of the water in which it lives. Populations usually explode during the warmth of late summer and early autumn. Narraganset Bay has warmed an average of 3.4 degrees F. during the past 20 years, while between the late 1970s to 2001, the average temperature of Long Island Sound during for the first three months of each year has increased about 8 percent, from 37.4 degrees F. to 40.2 degrees F.

In 2013, a United Nations report found that overfishing in the Mediterranean and Black Sea was removing top predators, as jellyfish populations jumped. The report, “Review of Jellyfish Blooms in the Mediterranean and Black Sea,” published by the “UN Food and Agriculture Organization’s General Fisheries Commission,” said that “It is clear that a new type of human approach to marine ecosystems in general is needed to prevent and face a phenomenon such as the jellyfish blooms.” The FAO report the jellyfish prey on fish eggs and larvae as they compete for the same food sources as fish populations that already are declining because of overfishing.

In coming years, jellyfish could replace fish in the world’s oceans, according the report, which raises the possibility of “a global regime shift from a fish to a jellyfish ocean.”

Welcome to the future.

Bruce E. Johansen is Jacob J. Isaacson Professor at the UNO and author of The Encyclopedia of Global Warming Science and Technology (2009).

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