DNA detective work has shown showing that restaurants not only in the US but South Korea illegally sold whale meat from Japan. Japan, Iceland and Norway who all want to resume commercial whaling have previously stated that they can prevent whale meat smuggling by matching the DNA of the meat sold in markets to a register of all legally caught whales - however all countries have refused to make their DNA registers public.

Scott Baker of Oregon State University in Corvallis and colleagues secretly took samples from two restaurants, one in Santa Monica, California, and another in Seoul, South Korea and compared the DNA with that from samples bought in Japan. They discovered that they came from the same animals, proving that meat from whales hunted in Japan's scientific programme have been illegally sold abroad. The monitoring system can only clearly work if Japan, Iceland and Norway make their DNA registers publicly available, so routine checks can be carried out. The Japanese government does not release genetic identity records for the whales they kill, therefore it is difficult to link specific samples of whale meat to animals killed in Japan's whaling program.

Baker and his co-authors of the study are calling for Japan to share its DNA register of whales taken from its whaling program and bycatch whaling. The paper's authors also report on 13 whale products served at a sushi restaurant in Seoul, South Korea, during two 2009 visits. The sushi was part of a mixed plate of whale sashimi, and genetic testing found that four of the products were from an Antarctic minke whale, four were from a sei whale, three were from a North Pacific minke whale, one was from a fin whale, and one was from a Risso's dolphin. The DNA profile of the fin whale meat from the Seoul restaurant genetically matched products purchased by Baker's colleague, Naoko Funahashi, in Japanese markets in 2007, suggesting it came from the same whale.