Crayfish in Japan
This uniquely indigenous crayfish is called "Nippon zarigani"
which means "Japanese crayfish" in Japanese. "Japanese crayfish"
is native in northern area, Hokkaido and Touhoku, where "Japanese
crayfish" lives in a clean and cool water creek of low water temperature
well below 20 C. "Japanese crayfish" is not tolerant of higher
temperature and degraded water quality, and therefore cooler system and
powerful filtration are required to keep "Japanese crayfish"
in Tokyo, especially in its muggy summer. Though "Japanese crayfish"
are sold (in retail price of around \3000 or US$30 in Tokyo) in aquarium
shops during winter, this species is reportedly on the way to extinction.
"Japanese crayfish's" appearance and size (5 to 8cm or 2 to 3
inches) dose not necessarily attract crayfish keepers but its rareness
seems to attract them. "Japanese crayfish" used to be caught
for food or traditional medicine. The gastrolith, stomach stone, had been
actually handled as a sort of traditional medicine. But nowadays because
of development and its destruction of habitat circumstance, the number
of "Japanese crayfish" has steadily declined, and some local
governments declared "Japanese crayfish" as an endangered species.
Procambarus clarkii, known as red swamp crayfish, is predominant in major
islands in Japan. This species is imported from North America in 1920's,
and since then, the number of Procambarus clarkii has exploded because
of its high tolerance and freedom from predators. Procambarus clarkii can
be observed naturally in most ponds, swamps and rivers in three major islands,
Honsyu, Shikoku and Kyuusyu, and it is now invading even to Hokkaido.
Procambarus clarkii is called "America zarigani" which means
"American crayfish" in Japanese. "American crayfish",
especially reddish one, is popular among kids as a pet because of its easiness
to access and to keep. Majority of Japanese male must have their memory
that they had been crazy about catching "American crayfish" in
their childhood. Though Procambarus clarkii is aquacultured in North America
or Europe, quite a few people eat it in Japan. Aquarium shops sell "American
crayfish" not only for pets but also for feed for large carnivorous
fish. (Retail price is less than \100 or US$1.) These days, albino or blue
type of Procambarus clarkii was made and handled in aquarium shops in higher
price (of more than \3000 or US$30).
Pacifastacus leniusculus/trawbridgii living in Japan is called "Tankai/Uchida
crayfish". This crayfish was originally imported from North America
like "American crayfish" for farming in 1920's or 1930's, and
now lives naturally in Hokkaido, Ishikawa , and Tankai Lake in Shiga in
Honsyu. "Tankai/Uchida crayfish", Pacifastacus leniusculus/trawbrigii,
is good for food because of its high proportion of tail meat. In addition,
it attracts crayfish keepers because of its larger size than "Japanese
crayfish" and "American crayfish" and its robust appearance
in spite of mediocre brown color. "Tankai/Uchida crayfish" lives
in cool water and, therefore, the cooler system is needed to keep it in
Tokyo in summer. Retail price in aquarium shops in Tokyo is around \3000
or US$30.
However, in Febraury 2006, Pacifastacus leniusculus were totally banned
by the Special Alien Animal Law which imposes a violator the punishment
of no more than three-year-imprisonment. Ministry of Environment is making
efforts to eliminate Pacifastacus leniusculus from the ponds, reivers,
and lakes in Japan
Yabby, Red Claw, Marron and other imported crayfish had been becoming popular
among aquarium lovers. Actually more and more Yabbies, Red Claws and Marrons
were imported and sold in aquarium shops. Blue colored animals were higher
valued and sold in higher price. They were kept under artificial circumstances
and are reported not to be seen in natural places in Japan. Yabby has,
however, potential to be a new habitant in wild life in Japan because of
its tolerance on temperature and water quality. Competitiveness with first
comer, "American crayfish", may hamper its prevalence. Marron
and Red Claw do not seem to have potential to be habitant in Japan except
some particular areas because of their intolerance on high temperature
and low temperature respectively.
In Febraury 2006, all the Australian crayfish were also totally banned
by the Special Alien Animal Law which imposes a violator the punishment
of no more than three-year-imprisonment.
