Evolving Strategies for Managing Koi Herpes Virus (KHV) in Fisheries

Ensuring the health of fish populations and promoting sustainable fishing practices is a top priority for the Environment Agency. Collaborating closely with partners and fishery managers, the agency aims to mitigate the risks and impacts of fish health incidents, particularly those associated with Koi herpesvirus (KHV). This virus primarily affects carp and poses a significant threat to recreational fisheries due to the potential for extensive fish mortalities.

New Approaches to KHV Management

Beginning in 2026, the Fish Health Inspectorate (FHI) will implement a revised strategy for responding to and managing KHV in fisheries. This change represents a shift towards a more targeted, risk-based approach for handling the disease across England and Wales. The FHI will retain its responsibility for statutory surveillance and control of listed aquatic animal diseases, including KHV. The Environment Agency will continue to support the FHI in addressing both listed and emerging diseases while fulfilling its own commitment to safeguarding the health and resilience of fisheries.

The Role of the Environment Agency

The Environment Agency will maintain its critical role in addressing fish health incidents and minimising the risk of disease transmission between recreational fisheries. In instances of fish mortalities, the agency will:

• Investigate significant mortality events to uphold, enhance, and develop fisheries.
• Conduct thorough fish health investigations to ascertain the causes of mortality, subsequently advising on suitable management and biosecurity measures. Any suspicion of a listed disease will be reported to the FHI during these investigations.
• Provide fisheries with guidance and management strategies aimed at alleviating stress in fish during disease outbreaks, particularly in relation to KHV, where stress significantly contributes to the onset of clinical disease.

In cases where KHV is confirmed, the agency may refrain from issuing authorisations for the use of equipment at fisheries to aid recovery following a mortality event. This measure is designed to uphold robust biosecurity practices and minimise the risk of disease transmission to other fisheries until the threat has diminished. It is important to note that these actions complement, rather than replace, the FHI’s statutory responsibilities concerning disease surveillance and control.

Monitoring and Supporting Fisheries

The Environment Agency will also monitor fish health and mortality rates at fisheries. These efforts are intended to reinforce effective fisheries management and biosecurity practices, especially during times when the risk of KHV expression and transmission may escalate. Close collaboration with fishery owners will be essential in providing advice and support during outbreaks.

Furthermore, the agency will persist in its partnership with the Fish Health Inspectorate to safeguard the health of fisheries on a national scale.

Resuming Activities After Restrictions

Once conditions improve, applications for the use of equipment to facilitate fish movement may be approved after water temperatures have dropped below the thresholds associated with KHV outbreaks. Typically, this will occur when:

• Fish deaths have ceased, and
• Water temperatures have fallen below those conducive to disease expression.

The Environment Agency will collaborate with fishery managers throughout this process, offering guidance to support recovery efforts.

Key Responsibilities for Fishery Stakeholders

Fishery owners, managers, and anglers play a vital role in safeguarding fish health. Key actions include:

• Reporting fish deaths or signs of distress: Contact the Environment Agency incident hotline at 0800 80 70 60.
• Reporting suspected listed diseases: If a listed disease such as KHV is suspected, it is crucial to inform the Fish Health Inspectorate via email at fhi@cefas.gov.uk or by calling 01305 206700. A 24/7 on-call service is available for urgent inquiries, including disease reporting.
• Adhering to biosecurity best practices: Implementing good biosecurity measures and controls on fish movements is essential for preventing disease spread.

Commitment to Healthy Fisheries

The forthcoming changes aim to strike a balance between protecting fish health and alleviating unnecessary burdens on fisheries. The Environment Agency is dedicated to responding swiftly and effectively to disease threats while assisting fishery operators in managing their waters. Continuous review of strategies will ensure that the agency’s response to fish disease remains effective, practical, and proportionate, in collaboration with partners and stakeholders.