No, it doesn’t sound like the most appetizing thing in the sea, but manta rays are being overfished and eaten right onto the endangered species list. And it’s not even the whole manta that’s getting munched on––just their gill plates.

Manta ray at the Chura-umi Aquaruim, Okinawa, Japan. (Photo Credit: Ken Funakoshi)

In China, traditional medicine derived from exotic wildlife parts remains a thriving industry, regardless of the real health benefits of ingredients like rhino horn, scorpions or the penises of tigers and deer. China has driven the growing demand for manta gill plates, with 99 percent of the market and consumption of manta and mobula ray gills based in Guangzhou, a port city located north of Hong Kong. According to WildAid, a San Francisco-based conservation group, that market is now estimated at 138,000 kilograms a year, representing 147,000 slaughtered rays for an annual US$30 million in revenue. Sales of the gill plates have soared in recent years, due in part to the decline in the availability of large shark fins.

“Guangzhou has quickly become the hub of the manta ray gill trade, and our surveys suggest a surge in consumption that has more than doubled over the last three years,” said Peter Knights, Executive Director of WildAid.

Today, manta populations, already threatened and nearing endangered status, are declining worldwide. This animal, whose nearest relation is the shark, is being chopped up and transported to China where it’s stewed into medicinal concoctions that have no actual medicinal properties. On the contrary, the manta gills that are so popular in Guangzhou are in fact loaded with toxins.

Just like you wouldn’t eat the air filter in your car, eating the filter organ of a marine animal is not so great for your health. In the manta’s case, the filter is used to suck plankton out of the ocean – but the ocean happens to be a fairly polluted place. For instance, its mercury content has increased threefold over the past century. Toxicology tests performed on manta and mobula gill plates sampled in Guangzhou found not only dangerous levels of mercury, but also arsenic, cadmium, lead and other heavy metals. In some cases, the levels of arsenic detected were 20 times the levels permissible by the Pharmacopoeia of China.

How WildAid Is Turning China’s Stomach

The fact that manta gill plates are so toxic is helping WildAid change Chinese consumers’ minds about its palatability. Among the gill’s purported benefits are its ability to heal tonsilitis, detoxify blood, clear smokers’ lungs and increase the amount of breast milk. This last benefit has led to the gill being marketed specifically at nursing mothers, and made its potential dangers that much more potent.

In 2014, WildAid launched a demand reduction campaign in Guangzhou to raise awareness about the environmental and health impacts of the manta ray gills (known as “Peng Yu Sai” in China). “Together with assistance from the Chinese government and Traditional Chinese Medicine practitioners, we will raise awareness among China’s consumers of the trade of manta ray gills and the issues surrounding their alleged medicinal values,” said Peter Knights. “In an independent, public survey…we discovered that a majority of consumers are unaware that mantas are endangered and would gladly stop eating the gills once informed of this status.”

A major victory for the movement came late last month when Peru, home to the world’s largest-known population of giant manta rays, passed a ban on manta fishing. The resolution, passed on December 31 by the government’s Ministry of Production, also requires that mantas caught as bycatch be immediately released back into the ocean.

“My team and I are extremely proud to have generated legal action for the protection of giant oceanic manta rays in Peru through this Ministerial Resolution,” said Jesús Eloy Barrientos Ruiz, Director of Supervision and Fiscalization of the Ministry of Production. “We thus highlight our commitment to promote positive change within our fisheries sector. Our ultimate goal is to achieve sustainable fisheries and sustainable consumption in benefit of future generations.”

Applaud Peru & China for taking steps to protect mantas–majestic beasts that need our help: https://t.co/sJiynTW9pO pic.twitter.com/1YBTpPZZo0

— Paul Allen (@PaulGAllen) January 7, 2016

The resolution represents the culmination of years of advocacy work by WildAid, Planeta Océano and The Manta Trust. The ban will not only reduce the amount of mantas entering Chinese markets, it will also help grow manta tourism in the region, an industry that has already seen great success in Indonesia.

“Manta rays reproduce very, very slowly, and can be impacted by even limited fishing. Peru’s new level of protection is vital to their survival and paves the way for the development of a sustainable manta ray tourism industry, which globally generates $140 million every year,” said Peter Knights in a press release.