Nearly half of retail eel products in local supermarkets contain critically endangered species, scientists from a local university found.

The Division of Ecology and Biodiversity of the University of Hong Kong said the eel products contained European eel, a critically endangered species at risk of extinction as defined by the International Union for Conservation of Nature.

Due to over-exploitation to satisfy the growing demand from mainland China, as well as rising ocean temperatures, parasites and dammed rivers, glass eels are caught while swimming upstream in Europe and North Africa, and smuggled to Asia to breed for resale when mature, the HKU team said.

According to the study, since captive breeding of eels has not been economically viable, wild glass eels are caught and delivered to eel farms.

The trade in European eels and their food product derivatives is currently regulated by the Convention for the International Trade of Endangered Species, a multilateral treaty on conserving endangered species enforced since 1975, which also restricts the import and export of the species.

The research team, led by David Baker from the university's Conservation Forensics laboratory, said the trade in Japanese and American eels - two more common species - are not regulated and do not need a permit, meaning the "endangered European eels can be laundered along with their legally traded relatives."

"The international trade in glass eels is incredibly lucrative. One kilogram of glass eels can contain up to 3,500 individuals and has been recorded selling for over HK$50,000 on the black market," the team said, describing the trade as "highly profitable."

But the team noted that their ultimate destination remains unknown, even if the existence of Europe-Asia smuggling routes had been documented earlier.

"The numbers from Hong Kong are very alarming and reflect the huge amounts of European eels that are being farmed in Asia," said Florian Stein, director of scientific operations at Sustainable Eel Group.

He said the illegal export of glass eels was "one of the world's greatest wildlife crimes."

"The next step is to investigate the global consumer markets to identify where these trafficked eels are eventually consumed," he added.

The discovery comes from an undergraduate project studying seafood mislabeling, when the students found a significant amount of European eel products in local supermarkets.

Haze Chung, a year four undergraduate researcher, said the "exciting" findings have made an impact in illegal trading.

The university said the large-scale smuggling of European eels has suggested an "interwoven" connection between local supplier chains, resulting in the prevalence of endangered species in retail markets.

justin.tong@singtaonewscorp.com

Scientists found large amounts of endangered European glass eels in the local food supply.

Endangered eels onsale in local markets