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The Value of Angling - Anglers first to identify Killer Shrimp



Two keen-eyed anglers were the first to spot an unusual shrimp on Friday 3 September at Grafham Water and sent samples to the Environment Agency for identification. The shrimp was identified as possibly being dikerogammarus villosus, an invasive species, commonly known as the "killer shrimp". This is the first time this shrimp has been found in England, all due to the keen eyes of anglers, proving once again that we are the eyes and the ears of the waterside.

The shrimp is a voracious predator. It kills a range of native species, such as native freshwater shrimps and even young fish. It often kills its prey but leaves it uneaten. It tends to dominate the habitats it invades, sometimes causing the extinction of native species.

Insects such as damselflies and water boatmen, common sights on British lakes and rivers, could be at risk, with knock-on effects for the species which feed on them.

The shrimp has spread across most of Western Europe over the last 10 years. It can be as small as 3mm but grows up to 30mm long, much larger than our native freshwater shrimp.

Defra Fisheries Minister, Richard Benyon said: "I am extremely concerned to hear that this highly invasive species has been found in Britain.  Anglian Water has acted quickly to put biosecurity measures in place and the Environment Agency is working hard to establish the extent of the problem and what action may need to be taken.  We need to do everything we can to protect our native wildlife and young fish from the potential damage the killer shrimp can cause."

Expert biologists are currently testing water entering and leaving Grafham to see if the shrimp can be found in it. The results from this will indicate how widespread the problem might be and what measures need to be taken.

The shrimp could have arrived at Grafham in a variety of ways, naturally via birds, on wet boats or tackle or during a fish-stocking.

Dr Paul Leinster, Chief Executive of the Environment Agency said: "We are devastated that this shrimp has been found in Britain, and very grateful to the keen-eyed anglers who found it. We are currently establishing the degree of the problem, and whether the shrimp is only in Grafham Water or if it is in nearby lakes and the Great Ouse as well."

Ciaran Nelson from Anglian Water said: "We have put precautionary biosecurity measures in place around Grafham Water as containing the shrimp is of paramount importance. We are also assisting with investigations to establish if it is already more widespread. The presence of this species poses no risk to the quality of drinking water supplies.

"We are asking all water users at Grafham to take the actions asked of them on-site. This includes checking their equipment for shrimp when they leave the water and removing any that they find. They should also ensure their equipment is thoroughly cleaned and dried before it is put into any other water. Subject to these controls, recreational activities on the reservoir can continue."

Water users from Grafham wanting more information on the measures they should take can contact Anglian Water on: 08457 91 91 55, or via

If you think you have seen an unusual shrimp, please email a photograph to for identification.

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