A species of eel considered a culinary delicacy for Japanese diners in summertime has been placed on an international group's "red list" of endangered species.
The International Union for Conservation of Nature has added the Japanese eel, known in Japan as "nihon-unagi," to the Red List of Threatened Species.
In the wake of the IUCN listing, Japan's agriculture minister called for stepped-up efforts to boost eel populations to help the species recover.
Owners of Japanese restaurants that specialize in serving eel dishes are being hard hit by the decision. Japanese diners are estimated to consume two-thirds of eels eaten worldwide.
The listing of the Japanese species follows a similar "red list" classification by the IUCN of the European eel in 2008.
Although disappointed in the ruling, some Japanese restaurant owners said it didn't come as a surprise.
"Due to recent poor catch, I had predicted that the day of the listing would come someday," said Kihachi Chiba, a third-generation owner of a Tokyo eel restaurant called Chibaya.
At the restaurant, a "unaju" dish of grilled eels on a bed of rice served in a wooden box costs around $25.
Some customers at the restaurant said if the listing of the eels as endangered drives the prices even higher, they might consider giving up the popular delicacy.
"I can afford to eat eel dishes only several times a year. It is a small luxury for me," said a 65-year-old male worker for a Tokyo company. "But I may have to give it up."
People in Japan have been consuming eels for thousands of years.
Around 30 years ago commercial farming of eels began, started with young eels taken from the wild, but progress has been slow because of the eels' complicated migratory behaviors.
Eels spawn in remote ocean areas and then they migrate inland, only returning back to the ocean when mature and ready to reproduce.
"We must speed up efforts to build large-scale production systems," Yoshimasa Hayashi, the minister of Agriculture, Forestry and Fisheries, said.
That's considered one solution to the listing of the wild eel as endangered, experts said, noting wild populations were facing threats from pollution, waterway barriers and changing ocean conditions.
"Measures should be worked out to maintain this important food culture for Japanese people," said University of Tokyo marine resources professor Mari Kuroki.
The population of all eels globally has declined as much as 90 percent in the last three decades, the IUCN says.
In Japan, overfishing for consumption and to stock culture facilities has contributed to the decline in population, along with short-term changes in oceanic conditions, such as El Niño, typhoons, and global warming, which influence how many larvae survive. In addition, the Red List notes, there are more localised threats that include barriers to upstream and downstream migration, loss of habitat, pollution and the modification of habitat along the coast and in rivers.
