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California - Radioactive Tuna From Japan Nuclear Plant Crossed The Pacific To US

Published on: May 28, 2012 10:31 PM
By: AP
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Workers harvesting bluefin tuna from Maricultura's tuna pens near Ensenada, Mexico in March 2007.  AP FileWorkers harvesting bluefin tuna from Maricultura's tuna pens near Ensenada, Mexico in March 2007.  AP File

California - 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.

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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 planned 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.


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1

 May 28, 2012 at 11:56 PM hello101 Says:

Pretty scary. I live in the east coast and just bought fresh tuna. Should we eat this stuff or discard it?

2

 May 29, 2012 at 07:10 AM Respect Says:

Reply to #1  
hello101 Says:

Pretty scary. I live in the east coast and just bought fresh tuna. Should we eat this stuff or discard it?

The levels reported are well, well within the acceptable standards.

3

 May 29, 2012 at 07:59 AM 45128 Says:

Reply to #1  
hello101 Says:

Pretty scary. I live in the east coast and just bought fresh tuna. Should we eat this stuff or discard it?

“ Pretty scary. I live in the east coast and just bought fresh tuna. Should we eat this stuff or discard it? ”

Just what part of "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" did you find so particularly difficult to understand?

You could, of course, consult your local posek.

4

 May 29, 2012 at 10:42 AM Reb Yid Says:

I was wondering about that glow-in-the-dark sushi...

5

 May 29, 2012 at 11:56 AM YUBachur Says:

Reply to #3  
45128 Says:

“ Pretty scary. I live in the east coast and just bought fresh tuna. Should we eat this stuff or discard it? ”

Just what part of "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" did you find so particularly difficult to understand?

You could, of course, consult your local posek.

...assuming he knows about, and understands, radiation. Otherwise, what's the point?

6

 May 29, 2012 at 01:29 PM Anon Says:

Reply to #1  
hello101 Says:

Pretty scary. I live in the east coast and just bought fresh tuna. Should we eat this stuff or discard it?

There are reasons to either not eat tuna, or to at least limit your consumption of it. Radioactivity is not one, yet, though with the Fukushima reactor still in danger, who can say what the future will bring. As a top predator, tuna concentrates any heavy metals and other pollutants that are in its food. This is especially significant for pregnant and nursing women. Because of mercury content, the FDA recommends that pregnant women not certain types of tuna and limit consumption of canned tuna. You can search online for the recommendations. In addition, certain types of tuna are being fished to extinction, so you might consider eating other types of fish if possible.

7

 May 29, 2012 at 02:19 PM Timetokill Says:

Bluefin tuna has to be labeled as such. Until the next scare just buy albacore, yellow fin or skipjack.

8

 May 29, 2012 at 04:24 PM ShmuelG Says:

Reply to #6  
Anon Says:

There are reasons to either not eat tuna, or to at least limit your consumption of it. Radioactivity is not one, yet, though with the Fukushima reactor still in danger, who can say what the future will bring. As a top predator, tuna concentrates any heavy metals and other pollutants that are in its food. This is especially significant for pregnant and nursing women. Because of mercury content, the FDA recommends that pregnant women not certain types of tuna and limit consumption of canned tuna. You can search online for the recommendations. In addition, certain types of tuna are being fished to extinction, so you might consider eating other types of fish if possible.

"In addition, certain types of tuna are being fished to extinction"

So, what? What if some types of tuna do become extinct? There are plenty of other types of it to be consumed by everybody who wishes to eat it. Stop with that nonsense.

9

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