Asa zoological park of Hiroshima opened in 1971. Since then Asa zoo has been protecting Japanese giant salamanders. Although Japanese giant salamanders were designated as national treasure animal in 1983, the population was declining year after year. Meanwhile Asa zoo was trying to breed in captivity, at last the first generation of Japanese giant salamanders were born at the zoo in 1979. After that, the third generation was born between the couple of zoo-born salamanders.

Some wild Japanese giant salamanders live in the Sijihara and the Shousai Rivers that run through northern Hiroshima. With local people Asa zoo also took part in saving wild Japanese giant salamanders for over 30 years.