OSAKA endangered Japanese eels are thriving in a seemingly unlikely spot, the Dotonborigawa river that runs through the city's busy Minami entertainment district.
Eels were caught there for the first time as part of the academic studies conducted by Osaka Prefecture's Research Institute of Environment, Agriculture and Fisheries in November.
Yoshihiko Yamamoto, senior researcher at the institute's biodiversity center, said the finding shows an ecosystem that allows Japanese eels, which prey on earthworms, crayfish and other creatures, to live in the river.
Many people don't know that fish swim in the Dotonborigawa, he said. The discovery allows people to understand that a variety of living organisms are linked to each other in nearby areas. The Japanese eel is listed in the Endangered Class IB category on the Red List of the Environment Ministry, meaning it is at a high risk of becoming extinct in the near future.
The species also falls into the Endangered Class II division in Osaka Prefecture's red list.
Japanese eels have been found in other waterways in Osaka Prefecture, according to the research institute.
They had been thought of inhabiting the Dotonborigawa River for a long time, but there was no firm evidence of it.
In November, researchers from the institute and elsewhere set up longline and other traps in the river, capturing 11 eels measuring between 30 and 60 centimeters long. A 60- cm eel is slightly larger than those grilled, the institute said.
The researchers concluded that they are Japanese eels based on morphological characteristics and other features.
Some of the eels caught are on display through April 7 at a special exhibition themed on the endangered species that exist in nearby areas at the institute's biodiversity center in Neyagawa, Osaka Prefecture.