Radioactive bluefin tuna crossed Pacific to U.S.

This March 5, 2007 file photo shows workers harvesting bluefin tuna from Maricultura's tuna pens near Ensenada, Mexico. / File,AP Photo/Chris Park

(AP) 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 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.

[Overruled1]

Godzilla was spotted off an island in Alaska and was seen heading right for Tokyo.
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I don't care if the governments of Japan and USA tell me it's safe to eat.
We've heard that before, it's as safe as pink slime or meat glue....yummy eh?

No wonder Americans have higher heart disease than the rest of the world and need our medical system different because of it.

This is unacceptable behavior from all governments involved.
Now we have a dead Atlantic, an oiled up Gulf of Mexico and a radioactive Pacific, when will it end? When we can no longer sustain ourselves? By then we'll be living off of soylent green.
WAKE UP PEOPLE!
WAKEUP!!!

[cozzicon]

It's ok. Easier to eat sushi in the dark when you can see it.

[Tarzan98]

You frucking right!

[parisdakar]

Good. Maybe this will reduce Japan's ravenous demand for Bluefin Tuna, and save the species from extinction.

[mari1963]

Amen! I completely agree with you.

[GerryOregon]

Please please please. Stop with these articles on the consequences of reckless energy policies. We should be focusing on American exceptionalism and American Idol.

[mari1963]

And don't forget the articles on William and Kate.

[erasmus111]

I don't know how any of this could possibly be a freakin' surprise. Those reactors are STILL puking out major radiation. We need to be checking the radiation levels in ourselves. If you think we aren't getting it, then give your head a shake. They can say that it's not dangerous levels, but the fact remains we don't need any more radiation. Radiation NEVER leaves the body.

Here is some enjoyable reading.

http://news.sympatico.ctv.ca/home/fukushima_reactor_4_poses_massive_global_risk/85067920

http://www.infiniteunknown.net/2012/04/22/fukushima-is-falling-apart-are-you-ready-for-a-mass-extinction-event/#.T5h-CJUKIPA.facebook

http://sync.sympatico.ca/news/chemicals_in_tsunami_debris_could_pose_coastal_threat/fff6df13

[displeased2]

Wow, scary stuff. Thanks for the reads!

[erasmus111]

You are welcome, Displeased. : )

[micmac666]

"Damn you, Godzirra!"

[Diamonddavej]

The radiation in the Fish from the radioactive caesium was 33 times smaller then the natural radiation already there, it caused an approx. 3% increase in radioactivity.

[credibility2]

More hype for the vegan crowd...

[Skruffy1]

Once humans kill the oceans, the planet is done for. And we're sure working in that direction.