Invasion of the killer shrimps
No, it is not the title of a new Stephen King novel but the arrival in the UK of Dikerogammarus villosus. This large freshwater shrimp has its home waters in the region of the Caspian and Black Sea. However, the opening of the Rhone-Main-Danube canal has allowed it to progress through the Netherlands, Belgium, Germany and France.
Why are the Environment Agency and other government bodies concerned ?
D. villosis (aka, the killer shrimp) is an aggressive predator, which also reproduces quickly. It kills and feeds on native freshwater shrimps, young fish and insect larvae. Sometimes it kills but does not eat its prey, hence its name - the killer shrimp. For a short video of this killer in action see : http://el.erdc.usace.army.mil/ansrp/video/Dikerogammarusvillosus.mpg
Where it invades, it tends to dominate the habitat often resulting in the local extinction of native freshwater species. This alien invader can be as small as 3 mm BUT can grow to be three centimeters in length – much larger than our native freshwater shrimps. To date the killer shrimp has been found in three locations
DEFRA, in conjunction with the Environment Agency, Natural England and many conservation organisations, are acting together to launch a campaign to raise public awareness of this invasive organisms and to limit the spread of this killer. The key words of the campaign for all anglers, boating people, wind surfers and other recreational water users are CHECK, CLEAN and DRY.
It is important that all equipment and clothing are checked for the presence of this shrimp so that it is not transferred around the country. The shrimp can survive out of water but in damp situations for days! Preliminary studies have shown that the shrimps can survive in wet, folded waders for 15 days or 7 days on a folded but damp net.
Further information on these shrimps (and images) can be found at
https://secure.fera.defra.gov.uk/nonnativespecies/alerts/index.cfm?id=3
www.europe-aliens.org/pdf/Dikerogammarus_villosus.pdf
http://www.aquaticinvasions.net/2010/AI_2010_5_4_MacNeil_etal.pdf
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Discussion
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Found this same species some 39 yrs ago believe it OR not in a drain vent from an old brick clay pit Chapman’s pond in Cleethorpes. Saw it attack an average sized frog and leave considerable damage in a matter of seconds. Very recognizable as the shrimp picture above.
Only saw one do this tho and thought it strange.
Maurice Calliss
25 February, 2023