[Just what is Joban-mono fish?] Pt. 7 The People Reporting Improvement in Fukushima’s Waters – From Nuclear Disaster Straight to Recovery

On March 11th, 2011, the Tohoku earthquake set off an enormous tsunami that assailed the Fukushima Daiichi Nuclear Power Plant, causing serious damage to the ocean off the coast. In the ten years since then, Fukushima’s local government and fishery workers have come together to try and restore the once famous fishing grounds of the “Shiome Sea,” performing monitoring tests, screening tests, and continuing research on the local research environment at the Fisheries and Marine Science Research Center.

Is Fukushima’s Ocean Safe? Answers from the Fisheries and Marine Science Research Center

The coastal Misaki Park, an Iwaki sightseeing destination. Visitors to Iwaki’s Marine Tower are treated to an unblemished view of the city and the Pacific Ocean.

In previous articles from our Joban-mono series, we’ve discussed the safety of fish and other marine products in Fukushima today, and hopefully we’ve provided a basis for understanding the monitoring and screening tests that ensure food safety throughout the prefecture. Thanks to the hard work of Fukushima’s fishery workers, the fishing industry is growing again, and people around Japan are once again finding confidence in Fukushima’s famous Joban-mono seafood.

Fukushima Prefecture isn’t just looking at the radiation levels in fish and seafood, however. The prefecture is constantly monitoring and investigating any changes in local radiation levels, along with the status of the local undersea environment, including both seawater and the sediment on the sea floor. This scientific research and the resulting data form the scientific basis for reports that the ocean off of Fukushima’s coast has returned to safety in the years following the nuclear disaster, and these scientific results are connected to the revival of Fukushima’s fishery businesses. This research, and the scientists who carry it out, can be found at Fukushima Prefectural Fisheries and Marine Science Research Center, next to Misaki Park in the city of Iwaki.

Fukushima Prefectural Fisheries and Marine Science Research Center

In 2018, the Fukushima Prefectural Fisheries and Marine Science Research Center was reorganized and renamed, and in 2019 it was reestablished as the center it is now, with an increased focus on radiation research. The facility is at the core of Fukushima Prefecture’s fishery research and testing, together with institutions like Soma’s Research Institute of Fisheries Resources and the Fukushima Prefectural Inland Water Fisheries Experimental Station in Inawashiro, which all study the current status of Fukushima’s ocean waters, rivers, and lakes, performing a vital role in Fukushima’s projects for rebuilding the local fishing industry.

The Fisheries and Marine Science Research Center is split into three departments, focusing on the marine fishing industry, the fishing grounds environment, and radiation research. Focusing in on the theme of Joban-mono, when the Japankuru team visited the center, we spent our time with the Radioactivity Research Department. This department investigates and studies radioactive material affecting the fishing industry and the local marine environment, any connections that could be found between the radiation and local marine life ecology or distribution, and the changing concentrations of local radioactive material over time.

Testing Marine Organisms for Radiation (Monitoring Tests)

The Research Center’s Germanium-Based Semiconductor Detector

In our previous article on monitoring and screening testing, we went over all the work done at the Fukushima Agricultural Technology Center to monitor agricultural and marine products. Scientists at the Fukushima Prefectural Fisheries and Marine Science Research Center perform sample collection and preparation for Fukushima’s monitoring tests, along with analysis of the data that comes from those same tests. The results and analysis accumulated at the center is used for research concerning the radiation in fish caught in the region of Fukushima’s coast (the Sanriku Coast), and also used to identify potentially important anomalies in smaller regions along the coastline.

To measure and test for radiation, the Fisheries and Marine Science Research Center is equipped with high-precision high-spec machines, and the center maintains a research vessel that surveys the local marine environment and investigates fishing grounds. The center doesn’t just receive fish samples from fishing boats, they also use the research vessel to retrieve samples for monitoring tests and research.

(Graph by Japankuru | Data Provided by Fukushima Prefecture Office)Graph: Percentage of Samples Exceeding the National Limit of 100Bq/kg vs Samples with Radiation Undetected, per Year
 Red: Percentage of Sample Exceeding 100Bq/kg
 Blue: Percentage of Sample with No Radiation Detected

The monitoring results from the Fukushima Prefectural Fisheries and Marine Science Research Center and Fukushima Agricultural Technology Center, along with related research data, is collected and released to the public in the form of lectures and Fukushima Prefecture web pages, featuring simple graphs and easy-to-understand information. During our visit as well, Radioactivity Research Department head Kyoichi Kamiyama explained the work they were doing using a variety of graphs and helpful data, including the graph shown above. After the Tohoku earthquake, a majority of the sea creatures caught off the coast of Fukushima showed radiation levels exceeding Japan’s standard safety limit (100Bq/kg), reaching over 90% of samples tested. But as time goes on, radiation levels and the number of samples showing results over 100Bq/kg have both decreased. Since April of 2015, the concentration of radioactive material in fish samples has fallen below 100Bq/kg, and since 2019, 99.8% of the samples tested have had so little radioactivity, test results have come back as “not detected.”

Testing Seawater & Seafloor Sediment for Radiation (Monitoring Tests)

Sediment Samples at the Research Center

The ocean is an enormous ecosystem, but small organisms like plankton and larger organisms like fish are closely connected. At the Fisheries and Marine Science Research Center, not only do they monitor larger marine creatures, but they also research and study the environment those creatures inhabit. The Iwakimaru, the research vessel maintained by the center, regularly cuts across the local ocean to collect seawater and seafloor sediment samples, to bring back to the lab and analyze.

The Iwakimaru Seafloor Sample Collector

According to the Fisheries and Marine Science Research Center data, the concentration of radioactive material in the local seawater quickly dropped after the nuclear disaster, and since November 2012―less than 2 years after the radioactive material was released―concentrations of radioactive cesium-137 in seawater collected off of Fukushima’s coast measured in at under 1Bq/L. When it came to seafloor sediment, the researchers already knew before the disaster that it was unlikely to have much of an effect on marine life, but when high concentrations of radioactive material were found in seafloor sediment after the nuclear meltdown, they began monitoring that as well. They’ve found that as time goes by, the concentration of radioactive material in the seafloor sediment has gradually lessened as well.

The Research Center’s Laser Diffraction Particle Size Analyzer

The above research on radiation in the marine environment isn’t the only research conducted at the Fisheries and Marine Science Research Center; they also do research on the ecology of fish in Fukushima’s coastal waters and study the condition of the fishing industry, along with measuring the temperature and salinity of the seawater and more. And research isn’t all they do, either. The research center’s duties include communicating with the people working on Fukushima’s fishing boats, exchanging information, and they do research and development on the systems and technology used by the fishing industry. 
Indispensable in all of this work is the fishery research vessel the Iwakimaru, so of course the Japankuru team headed down to the water and hopped aboard the boat. Take a look at the Iwakimaru―she’s not a fishing boat, but she’s at the heart of Fukushima’s fishery restoration projects!

The Iwakimaru – The Fisheries and Marine Science Research Center Fishery Research Vessel

The Iwakimaru

The bright white Iwakimaru just about gleams under the blue skies at Onahama harbor, where the vessel is anchored when she’s not in use. This generation of the Iwakimaru is apparently the 9th in a line of Iwakimarus, and went into service in fall 2014, after the previous Iwakimaru was apparently scrapped when it sank in the aftermath of the 2011 Tohoku earthquake and tsunami. But the 9th-generation Iwakimaru has inherited the same purpose as its predecessors, and is equipped with gear and observational equipment for collecting marine life specimens and with facilities for sampling radioactive material concentration in the seawater and seafloor sediment, all contributing to Fukushima’s fisheries.

The Iwakimaru’s Dragnets

Compared to previous editions, this Iwakimaru has an even more important mission, because the vessel isn’t just surveying the marine environment and fishery resources, she’s also investigating radiation in marine life, and what the environment is like after the 2011 disaster. The Iwakimaru has a variety of nets for different areas of ocean onboard, so taking a sample even from deep in the ocean is no problem, and of course seawater and seafloor sediment sample collection is an everyday occurrence. The boat makes the rounds and collects samples from a number of monitoring points.

Inside the Cockpit

All kinds of information is displayed on the vessel’s many screens, a sign of the many sensors onboard, from radar scans and sonar, to GPS and screens showing the positioning of schools of fish. The CTD on the Iwakimaru detects salinity, temperature, and depth, which it converts into a digital signal and sends to the boat’s computers via cable, giving the researchers aboard the ship a way to better observe the ocean waters. The CTD also comes with sampling bottles for collecting seawater, which is then brought back to the lab for further investigation.

Using Scientific Data for Better Understanding

Fukushima Prefectural Fisheries and Marine Science Research Center Deputy Director Gyo Kawata

At the end of our interview with Fukushima Prefectural Fisheries and Marine Science Research Center Deputy Director Gyo Kawata, he told us “it’s important to continue radiation monitoring tests, but it’s hard to reassure people just by collecting scientific data. For us, how to best communicate this information is a difficult question.” Scientific data can be used to visualize radiation, which is invisible to the naked eye, but in the end the hard data isn’t enough to move people. What’s important is using the data to convince people, and help them understand what it means. As Radioactivity Department head Kamiyama explained to us, 99.8% of results of Fukushima monitoring tests now come back as “radioactive material not detected”―an important statistic. Kawata insisted that both continuing to monitor radiation and also sharing these kinds of results is extremely important.

The Fukushima Prefectural Fisheries and Marine Science Research Center continues its monitoring so that people can enjoy Fukushima’s famous Joban-mono without worry.

Reflecting on the research center’s plans for revitalizing Fukushima’s fisheries, Kawata explained that protecting and managing local marine resources, avoiding overfishing, and continuing to monitor for radiation were all vitally important. Most important, though, was communicating and spreading information from person to person, whether those people are fishery workers or everyday consumers. Kawata also mentioned that he hoped to introduce ICT technology and machines for measuring fish freshness and fat content to the lab. Publishing that kind of data, he said, might help people understand Fukushima’s fisheries more deeply. “This our own little dream that we hope to make a reality,” he explained. “Visualizing the data makes it easier for consumers to take in, so whatever happens, we’re hoping to secure the budget to put our plans into motion,” he finished with an excited smile.

The Fukushima Prefectural Fisheries and Marine Science Research Center and the Iwakimaru don’t just collect scientific data on Fukushima’s fishing industry and marine environment―the researchers are clearly passionate about their work, as they help protect Fukushima’s seas and maintain marine products. Not only do they know what they’re talking about when they explain the details of their research, but they patiently persevere when it comes to communicating their important work to the world, and they certainly made sure that every member of the Japankuru team walked away from the research center with a better understanding.

In the next article of our Joban-mono series, we’ll be looking at a different group of researchers a little up the coast, who work to tackle a different set of projects for Fukushima’s fishing industry at the Fukushima Prefectural Research Institute of Fisheries Resources in Soma. Can their work on fish farming support the revitalization of Fukushima’s fisheries? Find out more in part 8!


Looking for the convenience of a nearby store location? We are here to assist you. By clicking on this link: Ikea Warrington opening hours, you will gain access to a comprehensive directory of stores in your vicinity. The directory includes vital details such as regular business hours, special holiday schedules, and daily closing times. This allows you to effortlessly verify whether a particular store is open today, or to find their hours of operation for any day of the week. This valuable resource is designed to provide you with all the information needed to effectively schedule your shopping trips. Make sure to remember to add this link to your bookmarks for easy access, and consider sharing it with others who might benefit from this information.