Zarigani (Cambaroides japonicus) is a specie of crayfish which lives in only Japan.
Small size (6 cm) and grayish in color. Its claws of front legs are much weaker than other crayfish. Zarigani needs low temperature and high degree of water purity, so lives in upper steam of river or lake of highland. Distribution is Hokkaido and northern Tohoku (northern area of Honshu).
The Environmnetal Agency (now Ministry of Environment) of Japan has added it as Vulnerable Specie (IUCN category) to the Red Data List since 2000. It is thought that the causes of decreasement are corruption of water quality and the extention of American crayfish Pacifastacus leniusculus, which was imported in the 20th century and have constantly proliferated in northern Japan. And some suspect that American crayfish has carried some plague eliminating Zarigani.
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