Manta rays and manta ray products are in use for medical purpose in many countries across the Indian ocean. Stories about this animal were gathered and written by students. They are all part of a pedagogical project, funded by the National University of Singapore and the Université de Paris. The Bestiary site is a work-in-progress and a participatory educational tool, representing animals whose products or body parts are used to promote health and healing.

The Manta Ray

A Story by Ong Jun Xian

Manta Rays are the largest species of rays in the world; they are highly intelligent and dangerous. The sea creatures live in tropical, subtropical, and temperate ocean waters across the globe. There are two distinct species of manta rays, the reef manta ray, and the giant oceanic manta ray. The reef manta ray tends to live along coastlines in the Indo-Pacific whereas the giant oceanic manta ray lives in the world’s major oceans (Manta Rays, n.d.).

Giant manta rays typically live alone or in small groups. They swim with their mouths wide open, drawing in zooplankton and krill, which they sift through rows of tiny rakes that line their mouths called gill plates (Manta Rays, n.d.). 

Manta rays are classified as vulnerable by the IUCN red list status. The most significant threat to giant manta rays is commercial fishing. They are often caught as bycatch, or unintended catch but are also susceptible to target fishing for their gill rakers (Bowman, 2021 ). Manta rays are already threatened by target fishing, incidental capture and due to their gill rakers, the value of manta rays has increased in the international markets. Its grill rakers – sponge-like tissue between their gills – are often used in traditional Chinese medicines. However, what makes them highly vulnerable is the slow reproduction and their long life spans (Manta Ray, n.d.)

Despite having conservation measures in place, demand for manta rays’ gill rakers has increased dramatically in Asian markets (Giant Manta Ray, n.d.). However, gills of manta rays were not historically used for the purpose of traditional Chinese medicines (TCM). In the market that sells gill rakers, the thin filaments that manta rays used to filter food are sold for up to $500 per kilogram. TCM practitioners used these “rakers” also known as peng yu sai, as an ingredient in soups. They claimed that it would boost the immune system by reducing toxins and enhancing blood circulation although none of the purported medical claims are supported by any scientific proof or TCM texts (Platt, 2012).

Although Manta ray gills have never been officially recognized as traditional Chinese medicine, over the past decade the demand for manta ray gills has soared in the Chinese trade. The demand was fuelled not only by a renaissance of tradition but by an unscrupulous network of traffickers looking for new ways to profit from the Chinese appetite for wildlife (Levin, 2016). If the Manta rays are extinct, it probably will not cause a significant difference to the traffickers who are profit-driven and may well look for another source of wildlife for revenue.

What we can do is to educate TCM consumers about the medical claims of Manta rays being unverified, and avoid buying traditional medicines that contain ingredients of endangered animals such as manta ray gills, shark fin, pangolin, and many others. I do agree with the quote from the save the mantas campaign that if there are no consumers, there will be no unnecessary slaughtering.

‘Devil Fish’ or Manta Ray from page 178 in book‘Favorite Fish and Fishing’by Henshall, James A. (James Alexander), published in 1908 by New York, The Outing publishing company.

Value in Asian medicine

Retailers of TCM claim that the manta gills are a time-tested panacea for modern ills and that they can increase the amount of breast milk, detoxify the blood, cure chickenpox, and clear a smoker’s lungs (Levin, 2016). However, all these claims are not proven through research. A testimonial from a traditional medicine researcher at the China Academy of Chinese Medical Science in Beijing highlighted that even after reading many pharmacopoeias, none of them record the medical function of manta ray gills (Levin, 2016). 

Manta Rays’ gills contain arsenic cadmium and other lethal metals. They cause damage to vital organs of the body including the reproductive organs. Yet, TCM peddlers used to promote them to breast-feeding new mothers (Guilford, 2014). According to the World Health Organization (WHO), long term exposure to food that contains arsenic can cause skull lesions and various cancers. Another report published in the American Journal of Epidemiology also confirmed the findings that 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 (Lhee, 2016). 

Fortunately, WildAid, together with assistance from the Chinese government and TCM practitioners have launched a demand reduction campaign to raise awareness about the environmental and health impacts of the manta ray gills (Planet Editoru, 2016). How did the manta ray gill plates become mainstream? The gill is sold to consumers in brick-and-mortar stores and the remedy has gotten mainstream media airtime, including a special on a popular TV show featuring cooking demonstration which included a discussion on the health benefits of gills by a pharmacist from a local hospital. It is fortunate that organisations such as WildAid and even TCM practitioners spread awareness about the claimed ‘benefits’ of eating the manta ray gills which are a potential danger. Although its impact will not be greater than COVID19 or bird flu, the potential to translate into something worse exists.

References
Lhee, E. (2016, June 6). “Is that manta ray in your soup? It could be manta ray”. DW
Levin, D. (2016, January 6). “China weighs ban on manta ray gills, Sold in traditional market as modern panacea”. The New York Times. 
Guilford, G. (2014, June 13). “Manta rays and human babies are the latest victims of traditional Chinese medicine”. Quartz. 
Planet Editor. (2016, January 8). “Chinese consumers are dining on toxic manta ray meat”. Planet Experts. 
Flora, S. J. S., & Agrawal, S. (2017). Chapter 31 – Arsenic, Cadmium, and Lead. In R. C. Gupta (Ed.), Reproductive and Developmental Toxicology (Second Edition) (pp. 537-566): Academic Press.
Platt, J.R. (2012, January 17). “Manta rays endangered by sudden demand from chinese medicine”. Scientific American Blog Network. 
Bowman, W. (2021, February 21).  “What’s the difference between manta rays and stingrays?”. Howstuffworks. 
“Manta rays”. (n.d.). National geographic, (retrieved october 28, 2021).
“Giant manta ray”. (n.d.). Oceana, (retrieved october 28, 2021).
“Manta ray”. (n.d.). Wild for life, (retrieved october 28, 2021).