Cormorants now being linked to the spread of KHV

For years the cormorant has been regarded as angling’s public enemy No1.

This week that label has been further justified as experts reveal that the feathered predators could also be responsible for spreading the deadly Koi Herpes Virus (KHV).

Following one of the worst years on record for fish-kills at commercial venues, the Centre for Environment, Fisheries & Aquaculture Science (CEFAS) has stated that fish-eating birds, such as cormorants and herons, have the potential to transfer the killer virus from one lake to another.

Until now KHV, which has been responsible for the deaths of thousands of carp across the UK, was thought to have spread via either the movement of live fish or by contaminated nets used by anglers.

But it’s now feared that the disease could be transferred by the droppings of birds that have eaten infected carp, or even on the feathers of waterfowl that have come into contact with fluids secreted from decomposing fish.

“It’s possible that birds such as cormorants have the potential to spread KHV from one water to another,” said Dr Kevin Denham, head of the Fish Health Inspectorate at CEFAS. “It could be carried in their faeces and also in the undigested fish often regurgitated by cormorants when they’re startled.

“Decomposing fish that have died from KHV release oils and fluids into the water which could be transferred over a short distance by a bird that comes into contact with it.” Even though CEFAS is currently conducting research to find out more about the disease, given this recent revelation, it’s now feared that it will be impossible to stop the spread of the killer virus.

Barston Lake in Solihull, West Mids, tested positive to KHV in 2007, and owner Nigel Harrhy is one of many who is certain cormorants and other fish-eating birds are to blame.

“I’m convinced that KHV can be transferred by cormorant droppings and I’ve spoken to countless fishery owners who all agree,” Nigel told AT. “I know one man who owns 18 lakes and, despite fishing being allowed on just four of them, the carp in every one have KHV. They contained different stock and different water supplies, so how did the disease get passed on if it wasn’t birds which are free to move from one water to the other?

“Research must be done, otherwise I don’t see how we can protect our fisheries totally from KHV.”