Since the 2011 nuclear accident, fishery workers in Fukushima Prefecture have had an unprecedented and daunting undertaking to convince consumers that local fish are safe to eat.

Fishing has resumed on a "trial" basis and catches have been gradually increasing. Seven years on, radiation checks are now part of their routine before they can be shipped to markets.

Japan has a cuisine culture that is often synonymous with "sushi" overseas, and consumers value not just the safety but freshness of seafood.

There is one thing that they have apparently learned the hard way: easing consumer anxiety takes more than just time and radiation checks. And it's still a work in progress.

"Who could have imagined such checks would become necessary before the accident?" said Tadaaki Sawada, an official with the local fishery association in Fukushima.

"It's possible to argue for the safety of fish by presenting the data we collect. But whether that can reassure consumers is a different story," Sawada said.

The March 11 earthquake and tsunami triggered the crisis at the Fukushima Daiichi nuclear power plant, forcing local fishermen to stop catching and selling fish off the northeastern prefecture.

That wreaked havoc on the fishing industry that enjoyed coastal and trawl fishing to catch bonito, tuna, saury and flatfish, among other species.

Two currents -- Kuroshio from the south and Oyashio from the north -- meet off Fukushima, creating good fishing grounds.

After rounds of radiation checks, the number of fish species allowed to be caught on a trial basis has increased from three over the years and all species can be fished except 10 including a type of sea bream and sea bass.

As the region marks the seventh anniversary since the disaster, a turning point came earlier in the month. Some 100 kilograms of flatfish were exported to Thailand for the first time, more than a year after flatfish fishing resumed.

Local officials hope that the practice will boost the morale of fishermen and help Fukushima rebuild its reputation and expand sales channels.

The current plan is to ship as much as 1 ton of flatfish -- a local delicacy that used to fetch high prices in Tokyo and beyond -- to Thailand. Japanese restaurants there will serve the fish, according to people involved.

Yusuke Ujike has been part of the efforts to promote Fukushima products in Thailand. But he admitted that exporting fresh fish felt like a "sensitive" issue at first.

"As a company doing business in the food industry, we know how important food safety is," said Ujike, president of Allied Corporation Co., a Yokohama-based trading firm.

Ujike looked into how radiation checks are conducted on fishery products before he became convinced. Tapping into overseas markets should be a viable strategy, he thought.

"I can't financially support the local industry but my hope is that exporting fish will become a catalyst for Fukushima," Ujike said.

The Japanese government set its maximum limit for radioactive cesium in sea produce and other food items at 100 becquerels per kilogram, which it says is stricter than international standards.

Since April 2015, no fishery products tested have exceeded the 100 becquerels per kilogram upper limit, according to the prefectural government.

The Fukushima Prefectural Federation of Fisheries Cooperative Associations, for its part, has set its own limit much lower at 50 becquerels per kg, beyond which shipments will be halted.

At fish markets in Iwaki, a coastal city in Fukushima, consumers have more access than before to locally caught fish. But the volume is still low, as total catches in 2017 accounted for just over 10 percent of what they used to be before 2011.

Chiharu Ando, the mother of a 6-year-old daughter, said her worries about Fukushima products have eased as her knowledge has expanded.

"I was pregnant back then and hesitated to eat fish for the first two years or so (after the crisis)," Ando said. "Now I know how food items are checked."

Recent surveys show the percentage of consumers saying that the origin of food items matters or somewhat matters fell from 68.2 percent in 2013 -- two years after the calamities -- to 62.9 percent in 2017.

When asked about the reason, 27.9 percent said they prefer buying items that do not include radioactive substances in 2013, which compares with 16.5 percent last year, according to the surveys targeting over 5,000 Japanese people in various parts of the country.

Certain progress has been made in eliminating the stigma attached to Fukushima. People in the fishing industry and risk communication experts acknowledge the importance of keeping consumers updated and publicizing as much information as possible.

As time passes, the challenges facing the local fishery industry could be manifold.

More catches would mean revival of local fishing activity, but they will also raise the need for fishery workers to conduct more radiation checks.

Uncertainty is looming over whether fish from Fukushima will be fairly valued because increased supplies may result in lower prices.

"First off, it's important to see locally caught fish return to the shelves where they used to be, and hopefully sold in the same price range as before," said Sawada of the local fishery association.

"We've come this far since the crisis but there is still a long way to go toward full-fledged fishing," he added.