KOKONOGI, Japan (AP) — A blood-orange blob the
size of a small refrigerator emerged from the dark waters, its venomous
tentacles trapped in a fishing net. Within minutes, hundreds more were
being hauled up, a pulsating mass crowding out the catch of mackerel
and sea bass.
The fishermen leaned into the
nets, grunting and grumbling as they tossed the translucent jellyfish
back into the bay, giants weighing up to 200 kilograms (450 pounds),
marine invaders that are putting the men’s livelihoods at risk.
The
venom of the Nomura, the world’s largest jellyfish, a creature up to 2
meters (6 feet) in diameter, can ruin a whole day’s catch by tainting
or killing fish stung when ensnared with them in the maze of nets here
in northwest Japan’s Wakasa Bay.
“Some
fishermen have just stopped fishing,” said Taiichiro Hamano, 67. “When
you pull in the nets and see jellyfish, you get depressed.”
This
year’s jellyfish swarm is one of the worst he has seen, Hamano said.
Once considered a rarity occurring every 40 years, they are now an
almost annual occurrence along several thousand kilometers (miles) of
Japanese coast, and far beyond Japan.
Scientists
believe climate change – the warming of oceans – has allowed some of
the almost 2,000 jellyfish species to expand their ranges, appear
earlier in the year and increase overall numbers, much as warming has
helped ticks, bark beetles and other pests to spread to new latitudes.
The
gelatinous seaborne creatures are blamed for decimating fishing
industries in the Bering and Black seas, forcing the shutdown of
seaside power and desalination plants in Japan, the Middle East and
Africa, and terrorizing beachgoers worldwide, the U.S. National Science
Foundation says.
A 2008 foundation study
cited research estimating that people are stung 500,000 times every
year – sometimes multiple times – in Chesapeake Bay on the U.S. East
Coast, and 20 to 40 die each year in the Philippines from jellyfish
stings.
In 2007, a salmon farm in Northern
Ireland lost its more than 100,000 fish to an attack by the mauve
stinger, a jellyfish normally known for stinging bathers in warm
Mediterranean waters. Scientists cite its migration to colder Irish
seas as evidence of global warming.
Increasingly
polluted waters – off China, for example – boost growth of the
microscopic plankton that “jellies” feed upon, while overfishing has
eliminated many of the jellyfish’s predators and cut down on
competitors for plankton feed.
“These
increases in jellyfish should be a warning sign that our oceans are
stressed and unhealthy,” said Lucas Brotz, a University of British
Columbia researcher.
Here on the rocky
Echizen coast, amid floodlights and the roar of generators, fishermen
at Kokonogi’s bustling port made quick work of the day’s catch –
packaging glistening fish and squid in Styrofoam boxes for shipment to
market.
In rain jackets and hip waders, they
crowded around a visitor to tell how the jellyfish have upended a way
of life in which men worked fishing trawlers on the high seas in their
younger days and later eased toward retirement by joining one of the
cooperatives operating nets set in the bay.
It
was a good living, they said, until the jellyfish began inundating the
bay in 2002, sometimes numbering 500 million, reducing fish catches by
30 percent and slashing prices by half over concerns about quality.
Two
nets in Echizen burst last month during a typhoon because of the sheer
weight of the jellyfish, and off the east coast jelly-filled nets
capsized a 10-ton trawler as its crew tried to pull them up. The three
fishermen were rescued.
“We have been getting
rid of jellyfish. But no matter how hard we try, the jellyfish keep
coming and coming,” said Fumio Oma, whose crew is out of work after
their net broke under the weight of thousands of jellyfish. “We need
the government’s help to get rid of the jellyfish.”
The
invasions cost the industry up to 30 billion yen ($332 million) a year,
and tens of thousands of fishermen have sought government compensation,
said scientist Shin-ichi Uye, Japan’s leading expert on the problem.
Hearing
fishermen’s pleas, Uye, who had been studying zooplankton, became
obsessed with the little-studied Nomura’s jellyfish, scientifically
known as Nemopilema nomurai, which at its biggest looks like a giant
mushroom trailing dozens of noodle-like tentacles.
“No one knew their life cycle, where they came from, where they reproduced,” said Uye, 59. “This jellyfish was like an alien.”
He
artificially bred Nomura’s jellyfish in his Hiroshima University lab,
learning about their life cycle, growth rates and feeding habits. He
traveled by ferry between China to Japan this year to confirm they were
riding currents to Japanese waters.
He
concluded China’s coastal waters offered a perfect breeding ground:
Agricultural and sewage runoff are spurring plankton growth, and fish
catches are declining. The waters of the Yellow Sea, meanwhile, have
warmed as much as 1.7 degrees C (3 degrees F) over the past
quarter-century.
“The jellyfish are becoming
more and more dominant,” said Uye, as he sliced off samples of dead
jellyfish on the deck of an Echizen fishing boat. “Their growth rates
are quite amazing.”
The slight, bespectacled
scientist is unafraid of controversy, having lobbied his government
tirelessly to help the fishermen, and angered Chinese colleagues by
arguing their government must help solve the problem, comparing it to
the effects of acid rain that reaches Japan from China.
“The Chinese people say they will think about this after they get rich, but it might be too late by then,” he said.
A
U.S. marine scientist, Jennifer Purcell of Western Washington
University, has found a correlation between warming and jellyfish on a
much larger scale, in at least 11 locations, including the
Mediterranean and North seas, and Chesapeake and Narragansett bays.
“It’s
hard to deny that there is an effect from warming,” Purcell said.
“There keeps coming up again and again examples of jellyfish
populations being high when it’s warmer.” Some tropical species, on the
other hand, appear to decline when water temperatures rise too high.
Even
if populations explode, their numbers may be limited in the long term
by other factors, including food and currents. In a paper last year,
researchers concluded jellyfish numbers in the Bering Sea – which by
2000 were 40 times higher than in 1982 – declined even as temperatures
have hit record highs.
“They were still well
ahead of their historic averages for that region,” said co-author
Lorenzo Ciannelli of Oregon State University. “But clearly jellyfish
populations are not merely a function of water temperature.”
Addressing
the surge in jellyfish blooms in most places will require long-term
fixes, such as introducing fishing quotas and pollution controls, as
well as capping greenhouse gas emissions to control global warming,
experts said.
In the short term, governments
are left with few options other than warning bathers or bailing out
cash-strapped fishermen. In Japan, the government is helping finance
the purchase of newly designed nets, a layered system that snares
jellyfish with one kind of net, allowing fish through to be caught in
another.
Some entrepreneurs, meanwhile, are
trying to cash in. One Japanese company is selling giant jellyfish ice
cream, and another plans a pickled plum dip with chunks of giant
jellyfish. But, though a popular delicacy, jellyfish isn’t likely to
replace sushi or other fish dishes on Asian menus anytime soon, in view
of its time-consuming processing, heavy sodium overload and unappealing
image.
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