Sharks and Soup

From the salt-cured fish eggs of caviar to snails roasted in garlic, the human race has come up with many strange delicacies, some of which are offered locally.  In fact, Chicago’s Chinatown is famous for offering products derived from dried shark fins, such as shark fin soup – a broth delicacy containing fibers of cartilage from shark fins. 

Unfortunately, the controversy surrounding shark fin soup has little to do with its texture – several of the shark species from which the fins come are endangered or vulnerable, raising questions about their conservation.

In July of 2012, Illinois State lawmakers signed a law banning the sale, trade, and distribution of shark fins in the state, but many restaurants still had the delicacy on the menu, or a whole shark fin on display.  Recently, one of these restaurants was cited and fined for failing to remove a shark fin from their display case.

The fin was confiscated, and brought to The Field Museum for a written confirmation that it was indeed from a shark. 

“The fin is about 3 feet tall,” said Kevin Feldheim, A. Watson Armour III Manager of the Pritzker Laboratory for Molecular Systematics and Evolution at The Field Museum.  “We were able to confirm that the fin is from a shark, but we have not yet identified the species.”

Feldheim and his team will use something called DNA barcoding – the technique utilizes a short piece of DNA in an organism’s genome to identify it as belonging to a particular species. 

“In this case, we will amplify a short piece of mitochondrial DNA from the fin, sequence it, and then compare it to a database containing thousands of other versions of this segment from a variety animal species,” said Feldheim.  “We hope to be able to match the sequence we get to one that’s already in the database.”

Even though there is no ocean near Chicago, Feldheim and his team hope to raise awareness about the current and future status of shark species around the world, and the ways in which we can help to preserve them in our every day lives – just by paying attention to what we eat.

The fin will remain at The Field Museum as part of a collection, where it will be accessible to scientists and researchers from around the world.

Explore more about The Field Museum's study of all kinds of DNA in the Pritzker DNA Lab.