Accordign to the Choson Ilbo:

Clams and other seafood from North Korea are openly being sold in the South despite a ban on all trade with the North after the sinking of the Navy corvette Cheonan last year. Insiders say that is because customers prize North Korean fisheries products.

Some 30 vendors in the Garak Market and 20 in the Noryangjin Fisheries Wholesale Market sell shellfish from North Korea, including large clams and scallops. “We have openly labeled shellfish that come from North Korea because customers think they taste better,” a vendor said. “They’re between W1,000 to W3,000 cheaper than domestic ones but the quality is good” (US$1=W1,081).

North Korean shellfish have been brought into the South labeled as Chinese since the end of March. “Before the sinking of the Cheonan, North Korean shellfish was directly imported” labeled as North Korean, an official at the Seoul Agricultural and Marine Products Corporation said. “But since the ban on North Korean imports they’ve been imported through Chinese traders.”

According to the National Fisheries Research and Development Institute, demand for fish and shellfish from North Korea is rising in the South because customers shun Japanese seafood products due to concerns over radioactive contamination, while there are suspicions over the quality of Chinese products.