Imports of Japanese Koi are looking
increasingly unlikely this year as Koi Herpes Virus (KHV)
sweeps Japan. Matt Clarke investigates.
The chances of Koi being exported from Japan this year are
under threat as the Koi Herpes Virus (KHV) continues to spread
throughout the country. The epidemic has recently led to 60
carp breeders, whose fish have been affected by the virus,
agreeing to have all their fish destroyed. The affected farms,
which lie around Kasumigaura and Kitaura lakes, produce mainly
Once culled, the breeders will be unable to
produce fish for at least two to three years. They are set to
receive 250-300 yen (£1.35-1.60) per kilogram for any fish
The most recent reports state that the
disease is affecting food carp, Koi and also wild carp. Some
reports say that the disease has also hit Niigata, the world’s
top Koi-producing region. The outbreak, which killed 4000 Koi
in a single week, occurred in Ojiya, central Niigata. The fish
were kept in separate ponds, but were on a centralised
An official for the Association of
Carp Growers in Ojiya told the Daily Mainichi News: “We don’t
know the exact scale of the damage or where the carp came
An outbreak of KHV was also reported in western
Niigata on November 14, so fish movements around the
prefecture have been stopped in an attempt to contain the
As a further precaution, a number of
ornamental carp shows scheduled up to the end of the year have
been cancelled. These are reported to have caused havoc among
organisers and enthusiasts.
The breeders and
distributors behind Japan’s largest annual carp-grading show,
the All Japan Nishikigoi Promotion Association, have cancelled
their event scheduled for January. The cancellation of the
event is likely to hit breeders further, as it is said to help
raise prices for some fish.
It is thought that KHV has
been found in at least 22 of the 47 prefectures in Japan.
When the disease struck Indonesia last year, the
Japanese Agriculture and Forestries Ministry introduced
measures to limit the transport and disposal of infected fish,
and in July 2003 further restrictions were introduced
governing the importation of carp.
However, by then it
was already too late. Wide scale fish kills in the Okayama
Prefecture between May and July were later found to be caused
by KHV, suggesting that the virus had entered the country
Takaji Iida, the head of the Animal Health
Division at the National Research Institute of Aquaculture
told the Daily Yomiuri that the disease could recur this year.
The virus is less active at lower temperatures, so it is
plausible that when the water temperature starts to rise in
the spring, that many other farms with apparently healthy fish
could start to lose fish as the virus takes hold.
present, there is no single completely reliable method for
determining whether live carp are carrying the virus, so it is
almost impossible for suppliers to guarantee that their fish
are free of the disease.
In an effort to increase the
trade’s perception of the health of their Koi, suppliers in
Niigata have suggested that they expose disease-free common
carp to their Koi and then kill the common carp to determine
whether they have contracted the virus.
Davenport, chief executive of the Ornamental Aquatic Trade
Association (OATA) told PPM that the situation in Japan, and
especially in Niigata is still unclear. Some reports say the
disease is present in Koi but these are currently unconfirmed
and may prove to be incorrect.
Davenport said that
OATA’s recommendation of a minimum 14-day isolation period at
temperatures of 23-28°C/73-82ºF had been supported by
scientific study, and that any suppliers using the technique
would be ‘very unlucky’ to have infected fish pass through
All retailers and wholesalers stocking
coldwater and pond fish are strongly urged to adhere to the
OATA guidelines in order to protect their own businesses, the
UK aquatic trade and our native fish stocks.
copy of the OATA document on how to identify and deal with
KHV, email OATA’s chief executive Keith Davenport at
email@example.com, or visit:www.ornamentalfish.org
This item was first published in the January 2004
issue of the trade publication Pet Product Marketing.
Matt Clarke is
Practical Fishkeeping's Website and Technical
Editor. A former fish biologist, Matt holds two
diplomas, a degree and two higher degrees in fish
taxonomy and biology. He's kept fish for over 20
years and currently keeps cichlids.
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