Japan exported about $600 million worth of aquatic products to China in 2022, making it the biggest market for Japanese exports, with Hong Kong second. Sales to China and Hong Kong accounted for 42% of all Japanese aquatic exports in 2022, according to government data.
Radiation levels have decreased since the accident in 2011:
https://upload.wikimedia.org/wikipedia/commons/0/06/Fukushima_radiation_dose_map_2011-04-29.png
Note that on Safecast, you can enable “Crosshair” in the hamburger menu to see the actual numbers.
The central blob area is currently around 5 μSv/hr, so if you live there for a year it’s 44000 μSv, or 44 mSv. The xkcd chart says 100 mSv is the lowest one-year dose clearly linked to increased cancer risk.
So 3 years there equals measurable increased cancer risk.