EVEX fish health guidance for clubs & fisheries

What is EVEX?

EVEX is a serious virus that affects eels only. It was first found in wild eels in England in 2018 after unexplained eel deaths. The virus belongs to a group called rhabdoviruses and is known to cause problems across Europe and other parts of the world.

EVEX is one of the most important diseases for eels because it can make them very weak and can even stop them from completing their long migration to the Sargasso Sea, where they spawn.

What does EVEX do to eels?

Eels infected with EVEX may show:

• Lethargy (very tired or slow behaviour)
• Skin lesions
• Bleeding on the skin and fins
• Severe internal bleeding
• Weight loss (emaciation)

Some eels can look healthy at first, but the virus can still be present and dangerous.

EVEX can be fatal, especially when the eel is stressed or preparing for migration — a time when its immune system is naturally weaker.

Why is EVEX important?

European eels are already in big trouble. Their numbers have dropped massively in recent years, and scientists still aren’t sure why.

Diseases like EVEX make things worse because:

• They reduce survival during migration
• They weaken already stressed populations
• They may spread silently before symptoms appear

Even a small increase in mortality can have a huge impact on eel recovery.

What is being done?

To protect eels:

• Fish movement restrictions are in place for infected areas
• The Environment Agency is testing more wild eels for EVEX
• New tools are being developed to detect the virus from blood samples, meaning eels don’t have to be sacrificed
• Biosecurity advice has been issued to prevent spreading the virus between rivers
• Fishermen and anglers are being encouraged to report any sick or dead eels immediately