In Japan, July 27th is "Doyo no ushi no hi" (the Midsummer Day of the Ox), during the hottest season of the year. On this day, Japanese people eat eels as a custom, because eels are rich in nutrients. Japanese people used to eat domestic eels which suit Japanese taste, but in recent years, the share of imported eels has increased to 85% because domestic eels are much more expensive than imported ones.

In this month, however, a Japanese scientist announced to have succeeded in full cultivation of eels including spawn and hatch for the first time. They hope this achievement could make domestic eels more affordable for Japanese people.