On the fifth anniversary of the Fukushima nuclear disaster in Japan, the fish might be doing alright.
Sea life is now thriving in the estimated 3.3 millions tons of debris that settled on the seabed of the Sanriku Coast on the northeastern side of Japan's main island after the tsunami that caused the nuclear meltdown, reported the The Japan News, the English-language edition of the Japanese daily Yomiuri Shimbun, on Friday.
Citing research by the Japan Agency for Marine-Earth Science and Technology, the newspaper reports that more than 10 times as many marine organisms live in the artificial reefs created by the concrete, scrap wood and other debris than in clear areas.
"Ragworms, Gammaridea [shrimp-like] crustaceans and other marine organisms have made their homes there, and channel rockfish, conger and snow crabs come to prey on them," The Japan Times reported. "These areas may become fishing grounds in the future."
To make their findings, the Japanese scientists used a robot to take pictures of the ocean floor at maximum depths of around 3,300 feet and distances of 12.5 to 21.7 miles (up to 35 km) off the coast, the newspaper reported.
Nicholas Fisher, an environmental scientist at the School of Marine and Atmospheric Sciences at Stony Brook University in New York, hadn't studied the findings, but he said they gelled with other research into the effects of the meltdown on marine life.
Atomic energy wasn't creating mutants in Japanese waters like in the old-school Godzilla movies, he said.
"Do I think that the radioactivity is causing anything like an unusual pattern of growth or degree of growth for any species present in those waters?" Fisher asked in an interview. "I think not."
The radioactive isotopes that the Fukushima nuclear plant emitted haven't caused major problems for the local marine ecosystem so far because they either had short half lives — so they've decayed into harmlessness — or ocean currents pulled them out and diffused them throughout the Pacific Ocean, said Fisher. "There's a dilution," he said.
Woods Hole Oceanographic Institution researchers have detected elevated levels of strontium-90 and cesium-137 in the Pacific, but at levels that are still well under US government safety limits. Those isotopes have half-lives of around 30 years, meaning it takes 30 years for half of their atoms to disintegrate.
Local fish wholesaler Nagamasa Takahashi places fish products into a radiation detector at his warehouse at Soma port, Fukushima prefecture, Japan, 26 February 2016. Photo by Everett Kennedy Brown/EPA
The findings near Japan suggested that the nuclear plant is still leaking radioactivity into the sea, however.
"Levels today off Japan are thousands of times lower than during the peak releases in 2011," said Woods Hole radiochemist Ken Buesseler in a press release on Monday. "But we are not seeing the steady decrease we would expect to see off Fukushima if all sources had stopped; rather, we are finding values are still elevated, which confirms that there is continued release from the plant."
Greenpeace Nuclear Policy Analyst Jim Riccio said it was too soon to tell if sea life has or hasn't been adversely affected in the wake of the disaster. Greenpeace is now conducting tests of the seabed off Fukushima, he said, to determine for sure whether and to what extent creatures there are contaminated.
He noted that the towns surrounding the nuclear plant were still evacuated and that Japanese academics had calculated that the financial cost of the disaster was $118 billion so far. People will be coping with the disaster for years to come. Marine life faces the same predicament, he said.
"No one is trying to overstate the impact," Riccio told VICE News. "But it does a disservice to downplay the potential health impact. It's only been five years. Thyroid cancer takes a while to show up."
Time will tell whether Riccio is right. But Fisher said the fish near Fukushima were lucky the ocean currents cleaned out the coastal waters.
"None of us, including myself, would pooh-pooh the amount of radiation that was released," said Fisher. "In terms of the impact on sea life, every case is going to be different. There might be some cases where the water is not well-flushed. Suppose it was in western Long Island Sound, which is not so well-flushed. Or San Francisco Bay. Then the stuff doesn't get diluted so much and it doesn't disperse over millions of square miles. It can become a very serious problem."
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