The killer shrimp has only been found in a handful of locations in England and Wales but due to its small size and its ability to survive in damp conditions it can spread easily and is considered a very real threat. The killer shrimp is a voracious predator of native invertebrates and as a consequence can cause disruption to the freshwater ecosystem directly through predation and can also indirectly effect the food chain. Changes in the food chain could alter the distribution of fish, whilst parasites carried by the killer shrimp could reduce fish stock.
Killer shrimp (Dikerogammarus villosus)
Killer Shrimp (Dikerogammarus villosus)
Native Shrimp (Gammarus pulex)
Tail with distinctive cone like protrusions
Tail without cones
Usually has a stripped back (although can sometimes be uniform)
Larger size than nature shrimp. Can grow up to 30mm but usually 10-20mm
No dark stripes
Smaller than killer shrimp, usually 11mm but can grow up to 20mm
How did they get to the UK?
First recorded in the UK in 2010, the killer shrimp originates from the Ponto-Caspian region and is found in large rivers in the Black and Caspian Sea basins. The opening of the Danube-Main-Rhine canal in the early nineties allowed the killer shrimp to expand its range naturally as well as being transported in ballast waters.
What can I do to prevent it spreading?
The killer shrimp can be transported on surfaces such as waders, boats and angling equipment. It can survive for many days in a damp crease in waders or fishing nets. For this reason we urge ant river users to follow the check, clean, dry advice before moving between water courses.
Check your equipment and clothing for live plants and animals – particularly in areas that are damp or hard to inspect.
Clean and wash all equipment, footwear and clothing thoroughly.
Dry all equipment and clothing – some species can live for many days in moist conditions.
Make sure you don’t transfer water elsewhere.