Researchers identify sashimi from restaurants in California and South Korea.
Scientific sleuths have used DNA barcoding to crack the case of the mysterious whale meat, in a tale that links a Californian sushi joint, Academy Award-winning film-makers and agents from the US National Oceanic and Atmospheric Administration (NOAA).
The evidence that led to the bust, and subsequent closing, of a sushi restaurant in Santa Monica is detailed in a paper published online today by the journal Biology Letters1. The authors, including scientists at Oregon State University in Corvallis who conducted much of the genetic analysis that identified the meat are pushing for closer monitoring of the trade in endangered whale products. On 12 April, the group formally requested that the government of Japan release its DNA registry of whale catch.
"I don't think we'll ever stop illegal trade," says author Scott Baker, a conservation geneticist and associate director of the Marine Mammal Institute of Oregon State University. "But we have to adopt better methods for identifying it, tracking it and controlling it."
The study is a particularly timely demonstration that it is possible to genetically identify meat in restaurants and markets, says Philip Clapham, a whale biologist at the National Marine Mammal Laboratory in Seattle, Washington, who edited the Biology Letters paper. The International Whaling Commission (IWC) is considering a proposal to lift its ban on whaling by certain countries, and a robust monitoring system should be part of the plan, Clapham says.
Baker and his colleagues sequenced the cytochrome b gene of mitochondria — cellular structures that provide cells with energy — from several sashimi samples, in a process known as DNA barcoding. Cytochrome b, an essential enzyme in cellular respiration, is frequently used to categorize species and create phylogenetic trees.
To identify individual whale samples, the team also used control mitochondrial DNA sequences and microsatellites — short genetic repeat sequences that vary in length and are useful in distinguishing individuals. Using this DNA profiling, Baker and his team compared the new samples to DNA from whale meat he and others purchased in Japanese markets in 2007 and 2008. The DNA profiles were a match, indicating that the meat, which is frequently frozen for several years before being served, probably originated from the same population of animals.
The scientists identified several different whale species in sashimi at restaurants in Santa Monica and Seoul, South Korea, including fin whale, sei whale and Antarctic minke whale. All of these are listed with the Convention on International Trade in Endangered Species (CITES), which prohibits the international trade of endangered species.
The whale meat samples were collected by conservation groups, the Ocean Preservation Society in Boulder, Colorado, and the Korean Federation for Environmental Movements in Seoul. The Ocean Preservation Society produced The Cove (2009), an Academy Award-winning documentary on dolphin hunting in Japan. At The Hump restaurant in Santa Monica, society members purchased the US$600 chef's choice plate, billed as a dish for the adventurous eater. The activists surreptitiously bagged samples, sold as 'whale' and 'horse', to send to Baker, who also took part in The Cove.
"I really didn't think it was likely to be whale," Baker says — particularly because it came from a top restaurant in environmentally conscious Santa Monica. He suspected that both samples would be horse. As it turned out, the 'horse' was beef, but the 'whale' was indeed endangered sei whale.
Baker turned his results over to the NOAA. The agency conducted another sting, in conjunction with members of the Oceanic Preservation Society. The analysis by the NOAA confirmed Baker's findings, and on 10 March 2009 federal prosecutors charged The Hump's chef and parent company with the illegal sale of a marine animal - an offence that carries a penalty of up to one year in prison and a fine of up to US$200,000 for the restaurant. Ten days later, The Hump closed its doors.
Louie Psihoyos, executive director of the Oceanic Preservation Society, suspects that The Hump is not the only restaurant peddling whale. After the filing of charges, he says, "there was probably whale meat in dumpsters all up and down the coast."
The study authors conducted a similar operation at a restaurant in Seoul. Whale meat is legal there, as long as it is accidentally caught in nets during other fishing operations. But DNA analysis showed that the restaurant was serving animals, such as the Antarctic minke whale, from waters that were not fished by South Koreans. DNA analysis matched the Korean meat to whale meat purchased earlier in Japan, confirming its out-of-country origin. The authors have notified Seoul's Metropolitan Police.
At its meeting in June, the IWC is expected to consider a new proposal on whaling. The plan would allow Japan, Norway and Iceland to hunt whales while reducing their quotas. Baker and Clapham suggest that an independent observer should monitor whale products, to ensure that quotas are followed. With Japan's DNA registry data, researchers could quickly determine whether whale meat was obtained illegally. The same method could be used for other endangered species, Clapham says. For example, 'bushmeat' sold in African markets is often from illegally poached wildlife, including endangered species such as elephant and gorilla.
Baker, C. S. et al. Biol. Lett. advance online publication doi: 10.1098/rsbl.2010.0239 (2010).
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Dance, A. Illegal whale meat tracked back to Japan. Nature (2010). https://doi.org/10.1038/news.2010.177