In 1927, Japan imported about 100 Louisiana crayfish to feed farmed bullfrogs, only 20 survived and their descendants later spread to every prefecture except Hokkaido

In the warm summer afternoons, Japanese children enjoy catching red swamp crayfish, a species introduced in 1927 for feeding American bullfrogs. After the closure of frog farms, these crayfish escaped into the wild, where they began to proliferate. Sadly, the…