Hong Kong (CNN)In a row of shops in Sheung Wan, on the western side of Hong Kong Island, the seahorses are stored in plastic boxes and glass jars, their elongated, S-shaped bodies stacked like spoons.
Used as a natural Viagra in Chinese medicine, seahorse numbers are declining
In Hong Kong, this district is the center of the trade in traditional Chinese medicine -- an ancient system that uses dried plants and animal parts to treat ailments. Its narrow streets are crammed with delivery trucks and men pushing trolleys loaded with crates of dried fungi, herbs, berries -- and seahorses.
In Chinese medicine, seahorses are believed to have Viagra-like powers. Hong Kong is the world's largest trading hub for the dried animal. Sarah Foster, program manager of Project Seahorse at the University of British Columbia in Canada, said that analysis of global trade data shows that Hong Kong was responsible for around two thirds of all seahorse imports from 2004 to 2017. The World Wildlife Fund has reported that their popularity as a medicine is also driving sales in China, Taiwan and Indonesia.
While nobody knows how many seahorse are left in the world, experts say they are under threat.
With their miniature equine snouts and beady eyes, seahorses look very different than most other fish. And unusually, it's the males that get pregnant.
But perhaps more importantly to conservation efforts, these are hard animals to study. Spread across vast oceans, some seahorses are less than an inch long and some can change color to camouflage themselves -- making them challenging to spot.
Foster said that about 37 million seahorses are caught in the wild every year. And despite regulations designed to protect them, smuggling is rampant.
According to Project Seahorse, research carried out around the world shows that populations of at least 11 species have dropped by between 30% and 50% over the past 15 years.
Seahorses were first mentioned in Chinese medical literature in 700AD but their use probably goes back much further, said Lixing Lao, director of the School of Chinese Medicine at the University of Hong Kong.
"According to Chinese medicine theory, seahorse is nourishing ... and gives the body more energy," he said. Mixed with herbs and boiled as a tea, dried seahorses are most commonly used to treat asthma and male sexual dysfunction, including impotence and premature ejaculation, he said.
Lao said there isn't there any scientific evidence that seahorses could relieve asthma or boost sexual performance, adding that there had not been any clinical trials carried out on humans in this area.
As a former British colony, Hong Kong sees a mix of both Western medicine and Chinese medicine -- there were 7,425 registered Chinese medicine practitioners in the territory in 2017, according to the Department of Health.
Seahorses retail in Sheung Wan for up to 40 Hong Kong dollars ($5) each.
A shop assistant in Sheung Wan, who declined to give his name, said that from what he has seen, seahorses are mostly bought by men over the age of 50. <