[Vision2020] Chick Kovis's Nightmare Becomes Reality

[Art Deco]

   <http://www.spokesman.com/> May 29, 2012
Giant radioactive fish cross the Pacific Ocean
Alicia Chang
Associated Press

Workers harvest bluefin tuna from Maricultura’s tuna pens near Ensenada,
Mexico. New research found increased levels of radiation in Pacific bluefin
tuna caught off the coast of Southern California. Scientists said the
radiation found in the fish came from Japan’s Fukushima nuclear plant that
was crippled by the 2011 earthquake and tsunami.

LOS ANGELES – Across the vast Pacific, the mighty bluefin tuna carried
radioactive contamination that leaked from Japan’s crippled nuclear plant
to the shores of the United States 6,000 miles away – the first time a huge
migrating fish has been shown to carry radioactivity such a distance.

“We were frankly kind of startled,” said Nicholas Fisher, one of the
researchers reporting the findings online Monday in the Proceedings of the
National Academy of Sciences.

The levels of radioactive cesium were 10 times higher than the amount
measured in tuna off the California coast in previous years. But even so,
that’s still far below safe-to-eat limits set by the U.S. and
Japanese governments.

Previously, smaller fish and plankton were found with elevated levels of
radiation in Japanese waters after a magnitude-9 earthquake in March 2011
triggered a tsunami that badly damaged the Fukushima Dai-ichi reactors.

But scientists did not expect the nuclear fallout to linger in huge fish
that sail the world because such fish can metabolize and shed
radioactive substances.

One of the largest and speediest fish, Pacific bluefin tuna can grow to 10
feet and weigh more than 1,000 pounds. They spawn off the Japan coast and
swim east at breakneck speed to school in waters off California and the tip
of Baja California, Mexico.

Five months after the Fukushima disaster, Fisher of Stony Brook University
in New York and a team decided to test Pacific bluefin that were caught off
the coast of San Diego. To their surprise, tissue samples from all 15 tuna
captured contained levels of two radioactive substances – ceisum-134 and
cesium-137 – that were higher than in previous catches.

To rule out the possibility that the radiation was carried by ocean
currents or deposited in the sea through the atmosphere, the team also
analyzed yellowfin tuna, found in the eastern Pacific, and bluefin that
migrated to Southern California before the nuclear crisis. They found no
trace of cesium-134 and only background levels of cesium-137 left over from
nuclear weapons testing in the 1960s.

The results “are unequivocal. Fukushima was the source,” said Ken Buesseler
of the Woods Hole Oceanographic Institution, who had no role in
the research.

Bluefin tuna absorbed radioactive cesium from swimming in contaminated
waters and feeding on contaminated prey such as krill and squid, the
scientists said. As the predators made the journey east, they shed some of
the radiation through metabolism and as they grew larger. Even so, they
weren’t able to completely flush out all the contamination from
their system.

“That’s a big ocean. To swim across it and still retain these radionuclides
is pretty amazing,” Fisher said.

Pacific bluefin tuna are prized in Japan, where a thin slice of the tender
red meat prepared as sushi can fetch $24 per piece at top Tokyo
restaurants. Japanese consume 80 percent of the world’s Pacific and
Atlantic bluefin tuna.

The real test of how radioactivity affects tuna populations comes this
summer, when researchers plan to repeat the study with a larger number of
samples. Bluefin tuna that journeyed last year were exposed to radiation
for about a month. The upcoming travelers have been swimming in radioactive
waters for a longer period. How this will affect concentrations of
contamination remains to be seen.

Now that scientists know that bluefin tuna can transport radiation, they
also want to track the movements of other migratory species including sea
turtles, sharks and seabirds.

-- 
Art Deco (Wayne A. Fox)
art.deco.studios at gmail.com
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