Shark fin soup isn't the healthy delicacy restaurants are claiming it to be

Photo: Getty Images.

Shark fin soup is a traditional Chinese dish that has become popular across the globe. It is viewed as a delicacy, so many restaurants are able to charge top dollar for the seafood broth.

With declining populations of sharks worldwide, there have been multiple bans on the sale of shark fins in the United States. However, some species are still allowed to be sold. It is also almost impossible to stop the sale of shark fins, Sea Shepherd says, because many Asian markets often lie about the species they have caught and laws aren’t always upheld.

This so-called delicacy also leads to some major health problems.

The reason indulging in this dish can be so harmful is because of bioaccumulation, explains the Shark Research Institute. Toxins concentrate in animals when they move up the food chain. Since sharks are some of the largest and longest-living species in the ocean, they have a high position on the food chain, so they consume huge amounts of toxins that have accumulated in their prey.

A study published in Science of the Total Environment in 2014 measured levels of monomethylmercury (MMHg), the most toxic and volatile form of mercury, in 50 dried unprocessed fins of 13 species found in international trade, as well as 50 samples of shark fin soup prepared in restaurants across the United States. They found that concentrations of MMHg in fins ranged from 9 to 1720 ng/g and concentrations in fin soup were 0.01 to 34 ng/mL. The highest values came from sharks at the top of the food chain, like hammerheads. The consumption of a 240 mL bowl of shark fin soup containing high MMHg concentrations is 17% more than the EPA’s recommended amount.

This is a major problem for expecting mothers. A 2015 study published by researchers at Rutgers University measured mercury levels in different fish species in New Jersey. They found that most mako sharks, a fast-swimming large mackerel shark, has mercury levels exceeding 1.0 ppm, with the highest being 1.8 ppm.

Less than 2 parts in a million may seem trivial, but the US Environmental Protection Agency has set the limit at 0.3 ppm and the US Food and Drug Administration set their own level at 1.0 ppm. The US FDA has said that pregnant women should avoiding eating shark meat because prenatal doses can lead to behavioural deficits in infants and lower results on cognitive performance tests.

More symptoms of mercury poisoning can include harm to the brain, heart, kidneys, and immune system.

University of Miami researchers published a study in 2012 on a cyanobacterial neurotoxin (a nervous system-affecting toxin produced from photosynthesizing bacteria) known as BMAA. They sampled fin clips from 7 different shark species in South Florida. BMAA was detected in fins of all species they examined with concentrations ranging from 144 to 1836 ng/mg wet weight.

Sharks found both in areas with cyanobacterial blooms and without had the toxin in them, possibly due to their migratory lifestyles. This study found that shark size or lifespan didn’t have a significant effect on how much of the toxin was present. This means that even if the fin in your shark fin soup is from a smaller shark, there is still a chance it could be affected.

BMAA has been linked to neurogenerative diseases like Alzheimer’s disease and Amyotrophic Lateral Sclerosis (ALS). Eating shark fins can increase human exposure the toxin. Scientists at the Dartmouth-Hitchcock Medical Center have published evidence suggesting this could be due to BMAA being improperly incorporated in the skin, leading to problems in the formation of connective tissue.

So while shark fin soup may appear to be an extraordinary dish to indulge in on a special occasion, it is definitely dangerous. Although there are bans, the soup can still be found in restaurants across the nation. Be sure to think twice the next time you consider ordering one of Asia’s most famous dishes.

NOW WATCH: Archaeologists made a groundbreaking discovery that unveils the mysterious origins of real-life hobbits

Business Insider Emails & Alerts

Site highlights each day to your inbox.

Follow Business Insider Australia on Facebook, Twitter, LinkedIn, and Instagram.