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In some parts of the world, people have been killing manta and mobula rays to use their gills for a so-called medicine. But eating these animals is threatening the future of the species and could be hurting our health.
Manta rays are vast, majestic creatures whose survival is under threat due to consumption of dubious health tonics.
I remember being fed Chinese medicine as a teenager. With a taste like earthy cough syrup, the bitter brown liquid came in clear plastic packets marked with Chinese characters. I didn’t know what was in it and whenever I asked my mother, I would always get the same answer. “Good, healthy ingredients” she would say, as she forced it into me. Every day for months on end.
She hoped the foul concoction would stimulate growth, but it didn’t seem to work its magic on me: I’m 5’1” (155 cm), which my mother still insists is because I didn’t take enough of the medicine.
Besides being unpleasant for those receiving such remedies, they could be contributing to an ongoing global tragedy. By not knowing what they ingest, people may unintentionally be supporting an industry that hunts threatened species, such as the manta and its close relative the mobula ray. Both are killed for their gills, which are used in the production of a pseudo-medicinal soup and health tonic known as Peng Yu Sai. Because the species reproduce at such low rates - spawning between five and 15 young in a lifetime - depleted populations take a long time to recover, making them particularly vulnerable.
An estimated 99 percent of the world’s manta gill consumers are concentrated in Guangzhou, China. US non-profit, WildAid, says around 138,000 kg of manta and mobula gill plates, culled from almost 150,000 creatures and worth $30 million, pass through the city annually. The organization is working to end the illegal wildlife trade by supporting marine protection and reducing demand through public awareness campaigns.
A market vendor sells manta and mobula ray gills in Guangzhou, a major hub in the manta gill plate trade.
Although the dried gill plates are not officially recognized as traditional Chinese medicine, vendors promote Peng Yu Sai as “healthy,” claiming it prevents, relieves, or cures a range of complaints, from chronic coughs to chicken pox to cancer.
In addition, new mothers are encouraged to drink the soup, which allegedly boots lactation.
Far from healthy
But WildAid China’s Chief Representative May Mei says such health claims are “nonsense.”
“The soup is seen as a kind of magic medicine that can cure everything,” Mei told Global Ideas. “People use it like Chinese medicine although it’s not even approved as a Chinese medicinal remedy.”
What’s more, a WildAid report from June 2014 says manta and mobula gill plates found on the markets in Guangzhou are contaminated with arsenic, cadmium, lead and mercury. A separate independent investigation led by Chinese media network, Southern TV Guangdong, confirmed the findings.
The levels of arsenic recorded in the WildAid report were four times higher than those deemed permissible by the World Health Organization (WHO). Cadmium was almost five times the recommended amount.
According to the WHO, long-term exposure to food containing arsenic can cause skin lesions and various cancers - particularly skin, bladder and lung. It has also been linked to developmental effects, cardiovascular disease, neurotoxicity and diabetes. For its part, cadmium can accumulate in the kidneys and cause irreversible damage.
A report published in the American Journal of Epidemiology says pregnant women exposed to arsenic are at increased risk of miscarriage and stillbirth, while babies carried to full term are more likely to die in infancy.
Campaigning for public awareness
But Dr. Severin Bühlmann, founder of Phytax, a laboratory that analyzes the purity of drugs, including those in traditional Chinese medicine, says heavy metals such as the ones found in manta and mobula rays, accumulate in animals high up in the food chain and have even been detected in plants such as mushrooms.
“No one really knows about the long-term effects of heavy metals,” Bühlmann said, adding, however, that consumers would need to be eating gill plates regularly for many years to reach the levels of toxicity cited in the WildAid report.
Last June, the organization launched a social multimedia campaign to inform the public about the effects of Peng Yu Sai both on manta and mobula ray populations, and on human health. Focusing efforts in Guangzhou, the group posted billboards in the subway system and engaged popular actors like Chinese idols to star in TV commercials.
Before this campaign, WildAid’s Mei said people were blissfully ignorant of the wider issue.
“Most people had no idea what a manta ray was, where the soup came from and what the fish looked like,” Mei said. “After the launch, people started to realize what they were eating.”
Chinese actor Wu Xiubo calls for an end to the killing of manta and mobula rays in WildAid's social multimedia campaign.
Getting to the bottom of it
The conservation NGO is continuing work with the Chinese government to ultimately ban the sale and import of manta and mobula gill plates. So far, there have been no nationwide policy changes, but an informal WildAid market survey from October registered a fall in both the supply and demand of gills in Guangzhou.
As for knowing what you are eating, I called up my mother while researching this story and asked her if there was any way to find out what made up that acrid brown liquid that became a feature of my adolescence.
“Of course,” she said, as she promptly googled “height-inducing Chinese medicine” in Korean.
It seems the growth tonic always contained hartshorn, which is the horn of a male red deer, and safflower seeds. As for the other ingredients, we may never know.