Killer and demon shrimp

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Every hour enough plastic to fill two bin bags is washed into our oceans from canals and rivers.

Killer shrimp and Damon shrimp are two freshwater shrimp species (Dikerogammarus villosus and Dikerogammarus haemobaphes). Individually they are highly invasive, but we now have both in the UK, which is worrying for our freshwater habitats.

KIller shrimp on white background Killer shrimp, copyright GBNNS

Native to the area around the Black Sea, both shrimp species have spread over western Europe in the last 20 years, most probably through commercial shipping. Killer shrimp were first discovered in the UK in 2010, while demon shrimp were first found in 2012.

More is known about killer shrimp, which live for about one year and are fast breeders, with the females able to produce three broods, each with an average of 150 eggs per brood. Killer shrimp can tolerate a range of environmental conditions, but they prefer to colonise waters with moderate to slow flow speeds, instead using faster-moving water to drift to new locations.

Killer shrimp are considered to be one of the most damaging invasive species in Europe, with the potential to significantly affect the ecology of our waterways. The shrimp preys on a range of native animals, fish eggs and even young fish. It often kills its prey and leaves it uneaten. This alters the ecology of habitats it invades, and could cause extinctions.

Both shrimp species and their eggs can easily be transported around in damp clothing and equipment as they can survive for a surprisingly long while out of water. Please follow Check, Clean, Dry procedures when you are out and about.

Last date edited: 29 August 2018