Dear Editor.


re: Koi Herpesvirus (KHv) Outbreak


There has been much speculation in the angling press and in Internet chat rooms about this year’s serious outbreak of KHv disease, and the actions taken by the Environment Agency.


Here are the facts:


·         KHv only affects carp, including Koi carp.

·         There have been 12 confirmed cases of KHv disease this year in stillwater fisheries in England.

·         We will not issue any fish movement consents from these affected fisheries into any other water. But we have no powers to prevent the movement of fish from these affected sites on to fish farms.

·         We have no powers to close affected fisheries, although we advise them to do so.

·         10 of the 12 affected sites have been legally stocked with carp in the past 18 months. The other 2 have no record of being legally stocked.

·         We have identified the 10 different suppliers that have provided fish to one or more of the affected fisheries, and these suppliers received their fish from 26 different sources, some via holding sites.

·         In excess of 200 other fisheries have been stocked by the 10 suppliers or 26 source sites.

·         Potentially, there are several other secondary suppliers and sources that may have provided infected fish to the primary suppliers.

·         The majority of the affected fisheries have not received KHv vaccinated fish. (Note that there are a number of suppliers of vaccinated fish in the UK.)

·         We do not routinely screen for KHv when consenting carp introductions.  Unless the carp are clinically diseased it is very difficult to detect.  If fish are showing clinical symptoms then they would automatically fail a health check.


You will gather from this that the matter is far from straightforward, and that it is wrong to speculate that any one supplier or source is the cause of the outbreak. Given that most of the affected sites are not linked to KHv vaccinated fish and that many of those fisheries have received fish from more than one supplier, it is wrong to point to vaccinated fish as the cause of the outbreak.


We have two important priorities:


·         To contain the outbreak

·         To try to trace the source or sources


To do this we need the full co-operation of the fish suppliers, the affected fishery owners and of the many others that could potentially be affected if the outbreak escalates. Naming fishery owners and suppliers will do nothing but hamper our efforts, by discouraging the reporting of fish mortalities.


·         We will not consents any fish movements from the 12 affected fisheries

·         We will not consent the stocking of fish from any of the potential sources unless they can be tested clear of KHv.

·         On our behalf, Cefas will continue to test waters that may be affected by the outbreak.


We appreciate that anglers and fishery owners are concerned about the further spread of the disease. The primary route for spread is the stocking of fish. The risk of transfer via angling tackle is negligible in comparison to moving carp between sites. As a precaution we are advising all fishery owners to put routine disinfection measures in place to protect against this and other fish diseases from infecting their waters. Anglers should thoroughly dry nets between fishing sessions. Advice on disinfection can be found on our website



Yours sincerely,




Adrian Taylor

Fisheries Policy and Process Manager