How did demon shrimp from the Caspian Sea reach England waterway? Conservationists raise 'threat to local species' alarm

A protected waterway in the UK has an invasive species: demon shrimps. This raises concerns, as they appear to threaten local species in the region.

Who are these demon shrimps?

Demon shrimps are small, semi-transparent, shrimp-like amphipod crustaceans. They feature a distinctive striped or banded pattern along their backs. Also known as *Dikerogammarus haemobaphes*, these shrimps are equipped with seven pairs of walking legs, or pereopods, and two pairs of antennae.

Where have they come from?

Demon shrimps originated in the Caspian Sea. They hitchhiked on boats and were then unknowingly spread further locally by kayakers and anglers.


These demon shrimps have been discovered in a tributary of the River Kennet, the Holy Brook. This channel of the River Kennet runs from near Theale through Calcot into Reading, Berkshire.

Locals alerted

Demon shrimps have the capability to outcompete native species. The charity Action for the River Kennet has alerted residents and urged them to report these stripy-backed demon shrimps if encountered.

ARK’s education and outreach manager, Anna Forbes, told the BBC that it was imperative that river users follow the government’s “Check, Clean, Dry” guidance to contain the spread.

"Check, Clean, Dry is really important. Demon shrimp eat little fish and fish eggs, are less effective at cleaning the water than native species and are highly aggressive. They don't belong in the mix."

The government’s guidance emphasizes cleaning and thoroughly drying all equipment and clothing after involvement in water activities.

In the South West, invasive signal crayfish from America continue to be a crucial issue at Prior Park Landscape Garden, Bath. This invasive crayfish species has previously caused millions of pounds’ worth of damage.

Piers Horry, garden and outdoor manager, told the BBC that these invasive species are difficult to remove once they are settled in the environment.

Horry told the BBC: "We've tried to eradicate them, but we were surprised how quickly that population boomed [after the damage was repaired]. We're looking into other methods, such as potentially introducing predators, to address the problem.

"Becoming a local action group can also help, and there is lots of support from authorities like the Environment Agency."