In Japan, an endangered eel was hiding in plain sight

The discovery in a polluted, touristy river is a shining example of wildlife’s resilience—but also raises concerns about their survival.

The Dotonbori River runs through Osaka’s tourism center. Lined with restaurants, shops, and businesses, the river was also recently confirmed to be home to endangered Japanese eels.

The narrow strip of murky water rippling along the concrete-lined banks of Japan’s Dotonbori River in Osaka may be the last place anyone would think to find wildlife, let alone an endangered species.

Japan’s third most populous metropolitan area, Osaka, is famous for its round-the-clock entertainment, endless shopping districts, and seas of crowds. At the heart of its bustling downtown is the Dotonbori River, where millions of tourists flock annually to bask under the iconic billboards, their multicolored glare spilling into the river. The water itself is not particularly attractive, with an expert once advising that swimming in it would be like “jumping into the toilet bowl.”

But the inhospitable depths of the Dotonbori hide a familiar creature: The river is home to Japanese eels, exactly the kind you would be served if you ordered unagi at a Japanese restaurant. Last year, the Research Institute of Environment, Agriculture and Fisheries, in the Osaka Prefecture, and the Mainichi Broadcasting System Television jointly announced the capture of 11 individuals in Dotonbori’s waters. It was the first record of live Anguilla japonica there.

The eels in these boat-laden waters are a shining example of wildlife’s resilience in urban centers, an encouraging sign for the species and a reminder that cities can be biodiversity refuges deserving of protection.

Yoshihiko Yamamoto, the institute’s lead researcher, says that he hopes that his team’s find will spark public interest in everyday conservation. “I'd like people to learn more about the connection between our daily lives and the places we live in,” he says. “If people think that eels and other aquatic creatures may be living in their local rivers, they will become interested in biodiversity and conservation.”

Riverine urbanites

Despite their name, Japanese eels live not only in and around the islands of Japan but also coastal China, the Korean peninsula, and the northern Philippines. After spawning in the ocean, the eels move inland, spending most of their lives in rivers and estuaries, like salmon but in reverse. Japanese eels can tolerate a wide spectrum of conditions, from brackish waters at river mouths to freshwater further upstream.

In an estuary in southwest Japan, fishers look for glass eels for aquaculture. Taken into captivity, the young glass eels mature into silver eels and are sold to restaurants.

Sourced from National Geographic