A "killer" shrimp has invaded UK waters and is feeding on native fish and insect larvae, a water company has warned.
Dubbed the "killer shrimp" by biologists for its appetite, dikerogammarus villosus often kills its prey and leaves it uneaten. The predator also alters the ecology of habitats it invades.
North West water provider United Utilities says a new fishing craze from the US is behind the spread of the crustacean, where anglers use "floating tubes" - large inflatable tyres - to fish on water. The tubes can help transfer eggs.
United Utilities confirmed it has banned the use of floating tubes at all its recreational reservoirs across the North West.
Originally from a region between the Black Sea and the Caspian Sea, the shrimp has spread across most of Western Europe in the past 10 years.
They can be as small as 3mm but may grow up to 30mm long, making it much larger than native freshwater shrimp.
Bosses at the company are working closely with the Environment Agency, county councils and fishery clubs that have licences to fish on its reservoirs to safeguard its waters.
Bryan Homan, water catchment operations manager, said on Tuesday: "Despite their fearsome name, the shrimp are not a threat to people, but the damage they could cause to our environment here in the North West is very real. Because of what they eat and the rate that they eat it, the shrimp can alter the food chain and our ecosystem, threatening native species."
He added: "To prevent the shrimp from entering our recreational reservoirs, we are today confirming the ban on the use of floating tubes. We're also encouraging all anglers who use our reservoirs to help us prevent the spread of the shrimp, by washing down all fishing equipment before and after use."
The shrimp was found in the UK at a reservoir in Cambridgeshire last September. It is believed the shrimp arrived in the UK from Eastern Europe on the hulls of ships.