Water Cooler

MENACE: Jellyfish Scourge Plagues World's Oceans

From Japan To New York City, Invasion Of Stingers Threatening Fishing Industry

Biologists Blame Global Warming, Killing Off Of Natural Predators & Pollution

NEW YORK (CBS) ― Swimmers are always keeping an eye out for sharks at the beach. But now, there's a new menace lurking in the water: Jellyfish. The stinging sea creatures are proving to be a major problem this summer, especially at New York area beaches.

From the beaches of the Mediterranean to New York's Long Island, swimmers are encountering huge swarms of jellyfish in the water on the shore.

"You could barely walk along the sand because there were so many jellyfish," said an unidentified Long Island swimmer.

There are always jellyfish in oceans in August, but this year, in some places, they arrived early. Scientists say there are more than ever before, and they're appearing in places where jellyfish have rarely been seen.

From Japan, Namibia and South Africa, and now right here in New York City.

Competitors in July's New York City Triathlon swam through jellyfish in the Hudson River. And in the surf off Long Beach, New York, thousands of swimmers have already been stung this summer.

"We didn't get these years ago, but now we're getting the frequency of them a lot more," said Paul Gillepsie, Long Beach Chief Of Lifeguards, who later added, "and they can be big, we've had some that were just tremendous that we've had to come and pick them off the beach because of the danger."

Marine biologists say the population explosion isn't just a nuisance, but a sign of the declining health of our seas.

"Jellyfish are really just a symptom of oceans in crisis," said Marine Scientist Margo Stiles.

Experts blame the worldwide invasion on several factors, including global warming, the overfishing of predators like tuna and pollution - primarily from the run-off from fertilizers to keep lawns green.

It turns out that jellyfish thrive in coastal waters where oxygen levels have been depleted by that run-off.

During a recent expedition to a lagoon on the coast of Spain, scientists from the Group Oceana were surprised to find a massive concentration of jellyfish.

"There were more than 20 million jellyfish in that lagoon right in front of the vacation homes, which is good for learning more about them, but not so good if you own one of those homes," said Stiles.

Marine biologists say the scourge, which in some places is overwhelming commercial fish stocks, will disappear in the fall as the water gets colder, only to return next summer, possibly in even bigger numbers.

(© MMVIII, CBS Broadcasting Inc. All Rights Reserved.)

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