Old habits threaten giant mantra ray

PUBLISHED : Sunday, 22 January, 2012, 12:00am
UPDATED : Sunday, 22 January, 2012, 12:00am


Growing demand from Chinese medicine practitioners for a little-known part of the giant manta ray is threatening the global population of the much-loved sea creature, conservationists say.

Researchers, including a Hong Kong-based conservation photographer, say the use of dried gill rakers from manta and mobula rays has risen dramatically in recent years as supplies have become scarce.

Gill rakers, thin filaments the rays use to filter food, are prescribed by some traditional Chinese medicine practitioners to treat everything from chicken pox to cancer, the researchers say. Practitioners claim the ingredient can 'boost the immune system and help purify the body by reducing toxins and fever and enhancing blood circulation'.

'Others claim that gill rakers will remedy throat and skin ailments, male kidney issues and help couples with fertility problems,' according to the 'Manta Ray of Hope' report, produced by conservation groups Shark Savers and WildAid.

The report says that the global populations of manta and mobula rays, also known as devil rays, are rapidly declining due to unregulated fisheries and, in part, demand for gill rakers.

The rays take up to 10 years or more to reproduce and when they do, they typically produce just one pup every two or three years.

One of the lead investigators was Hong Kong-based conservation photographer Paul Hilton, who started the manta ray project a few years ago when he noticed the gill rakers while researching another issue close to his heart: shark finning.

'We first came across manta and mobula ray gills in Asian markets several years ago and followed the trail to the dried seafood markets of Southern China,' he said.

The team investigated dried seafood markets in Hong Kong, Macau, Guangzhou, Singapore and Taiwan, with Guangzhou emerging as the centre of the trade.

In 2010, the team carried out DNA testing of gill rakers in Guangzhou, followed by investigations in Hong Kong.

The 40-page report claims that ecotourism from manta and mobula rays is worth more than US$100 million a year while the gill raker trade is about US$11 million.

Shark Savers director Michael Skoletsky said immediate action was needed to save the creatures from regional extinction.

'Anyone who has gone diving with mantas know them to be intelligent, graceful and engaging animals. It would be a tragedy to lose them,' he said.

Called peng yu sai in Cantonese, the gills vary in size according to the manta or mobula ray it has come from.

A handful of shops along Sheung Wan's Ko Shing Street sell the gills.

Fung Kam-chi, owner of the Shun Hing shop, said demand was growing and low supplies meant prices had more than doubled in recent years.

In 2006, a catty of small gill rakers would fetch about HK$300, but this same amount would now cost HK$750 to HK$850.

His stocks include large manta birostris gill rakers, which he said could be eaten with congee or in a soup to treat thyroid disease or chicken pox.

Fung, who said the gills came from Indonesia and the Philippines, also has smaller gill rakers from two mobula ray species: Chilean and Japanese devil rays.

A few doors down at another herbal medicine store Lee Yuen Hong, owner Ieong Kuok-ieng also confirmed that demand for gill rakers was on the rise but that supplies were not stable.

Customs officials and the Agricultural, Fisheries and Conservation Department could not provide statistics on the amount of manta or mobula ray gill rakers imported into Hong Kong.


According to NGO WildAid, the fins from more than this many sharks are used each year to make soup