In 1981, Japan imported golden apple snails as a new food business, but the market failed, and abandoned farms helped the snails spread into rice fields

Along irrigation canals and rice paddies across southern and central Japan, in prefectures spanning Kyushu, Shikoku, and parts of Honshu and the Ryukyus, farmers can spot clusters of bright pink eggs clinging to concrete walls and plant stems. They belong to the golden apple snail, known locally as "jumbo tanishi", an unwelcome fixture of Japanese agriculture for more than four decades.