Download Fishing co-operatives south of the Fukushima plant have banned the catches of one species of fish after radioactive cesium was found in a catch for the first time.
Cesium has a half life of 30 years and can accumulate on the ocean floor.
While authorities are calling for calm, consumers of seafood in Japan aren't so sure.
Mark Willacy of Radio Australia reports.
The average Japanese household consumes about 66 kg of fish every year.
Seafood is a culinary obsession, so anything threatening the safety of eating it is big news.
“Radioactive caesium above the legal limit has been found in small fish caught off the coast of Ibaraki just south of Fukushima.”
The radioactive caesium was discovered in a catch of young lance, a tiny fish usually caught in shallow seawater.
The Japanese enjoy eating it dried or cooked.
Five hundred and twenty six becquerels per kilogram of caesium was detected - above the 500 becquerel limit.
It could mean that radioactivity from overheated or melted fuel rods from the Fukushima nuclear plant has leached into the ocean.
The finding prompted 10 fishing cooperatives in Ibaraki, south of Fukushima, to immediately suspended catches of young lance.
"This is the perfect time for young lance fishing," says this fishing cooperative official. " This suspension is necessary but it will put people out of business. This radiation issue needs to be resolved soon", he says.
"I don't know how long this suspension will last", says this fisherman. "I hope the radiation will be contained as soon as possible", he says.
Caesium has a radioactive half-life of 30 years and according to scientists can accumulate on the ocean floor where shellfish live and feed.
While fishing cooperatives have suspended fishing of young lance, the government is simply going to raise the legal or acceptable limit of caesium in marine life.
"These fishermen have suspended fishing voluntarily", says government spokesman Yukio Edano. "The government will step up monitoring to look into the matter more closely rather than banning fishing across the board", he says.
Authorities insist consumers have nothing to fear but these assurances don't mean much to many fans of fish.
"I don't know what's going to happen", says this shopper. "I'm worried but I just can't stop eating fish", she says.
And it's that Japanese passion for seafood which the industry is hoping will get it through.
