Killer shrimp found in popular trout water could spread countrywide

Concern is mounting this week following the discovery of a new invasive species of shrimp that has the potential to decimate the ecosystems of British waters and day ticket fisheries.

As reported in last week’s Angling Times, the ‘killer shrimp’ has been found in the UK for the first time, sparking alarm within DEFRA and the Environment Agency after a number of the predators were spotted by anglers in Cambs’ Grafham Water.

Dikerogammarus villosus, indigenous to the Black and Caspian seas of Eastern Europe, has earned its name of ‘killer’ through its ability to kill and shred its prey without eating them. This trait can see the shrimp destroy populations of native species at a startling rate.

The invasion of the shrimp is of particular concern to anglers as the predatory species kills fish fry and eggs, as well as key fish food species of invertebrates such as native shrimp, nymphs and water boatman.

Speaking about the situation, a spokesman for the Environment Agency
commented: “The killer shrimp will attack a range of native freshwater species, particularly other shrimp and young fish. They alter the ecology of the waters they invade, leaving species locally extinct and severely restricting biodiversity.

“We cannot predict the precise impact the shrimp would have on the UK’s waters should it spread, but certain species could disappear from some locations and many others could become less abundant.

After invading other European countries, the shrimp has dominated its environment altering the ecology where it is present. Given the severity of the situation, as soon as the shrimp was positively identified, the EA put several biosecurity measures in place around Grafham to stop it spreading.

These include stopping the compensation flow out of Grafham and installing a mesh screen to prevent the shrimp escaping into the nearby brook, as well as checking the local waters for the species and conducting national surveillance.Anglers are urged to be vigilant and report anything suspicious.

Angling Times also spoke to Grafham Water fishery manager Jon Marshall. “The shrimp are here in pretty large numbers, but appear to have had no impact on the fishery so far,” said Jon.

“All we can do is act on what the EA has told us to do to make sure the shrimp doesn’t spread. All anglers and other users of Grafham are having their tackle and boots washed down when they leave and we are urging them to air dry their kit thoroughly.”