South Korea's Ministry of Agriculture, Forestry, Fisheries and Food announced on March 8 that an increasing number of marine products imported to South Korea from Japan have been found with radioactive cesium.
In most cases, the radioactive density was 7 becquerels/kg or less. The maximum was 97.9 becquerels/kg. Since they are all below the safety limit of South Korea, they have been sold in the market.
A becquerel is a unit of disintegrations per second and it's equivalent to 60 disintegrations per minute (a unit often used by Geiger counters).