Two keen-eyed anglers spotted
the unusual shrimp on Friday 3 September and
sent samples to the Environment Agency for
identification. Once the shrimp was identified
as possibly being Dikerogammarus villosus, the
Environment Agency worked quickly with Anglian
Water to put precautionary biosecurity measures
in place.
The shrimp is a voracious
predator (hence its common name of ‘killer
shrimp’). It kills a range of native species,
such as freshwater invertebrates, particularly
native shrimps and even young fish. This alters
the ecology of the habitats it invades. It often
kills its prey and leaves it uneaten. It tends
to dominate the habitat, sometimes causing the
extinction of native species.
Insects such as damselflies
and water boatmen, common sights on British
lakes and rivers, could be at risk, with
knock-on effects on the species which feed on
them.
It has spread across most of
Western Europe over the last 10 years. It can be
as small as 3mm but may grow up to 30mm long,
much larger than our native freshwater shrimp.
An expert in Holland has
conclusively identified the species.
Defra Minister, Richard
Benyon said: ‘I am extremely concerned to hear
that this highly invasive species has been found
in Britain. Anglian Water has acted quickly to
put biosecurity measures in place and the
Environment Agency is working hard to establish
the extent of the problem and what action may
need to be taken. We need to do everything we
can to protect our native wildlife and young
fish from the potential damage the killer shrimp
can cause.’
Expert biologists are
currently testing water entering and leaving
Grafham to see if the shrimp can be found in it.
The results from this will indicate how
widespread the problem might be and what
measures need to be taken.
The shrimp could have arrived
at Grafham in a variety of ways, including
boating, angling, fish-stocking or naturally via
birds.
Dr Paul Leinster, Chief
Executive of the Environment Agency, said: ‘We
are devastated that this shrimp has been found
in Britain, and very grateful to the keen-eyed
anglers who found it. We are currently
establishing the degree of the problem, and
whether the shrimp is only in Grafham Water or
if it is in nearby lakes and the Great Ouse as
well.’
Ciaran Nelson from Anglian
Water said: ‘We have put precautionary
biosecurity measures in place around Grafham
Water as containing the shrimp is of paramount
importance. We are also assisting with
investigations to establish if it is already
more widespread. The presence of this species
poses no risk to the quality of drinking water
supplies.
‘We are asking all water
users at Grafham to take the actions asked of
them on-site. This includes checking their
equipment for shrimp when they leave the water
and removing any that they find. They should
also ensure their equipment, (particularly
landing nets and keep nets), is thoroughly
cleaned and dried before it is put into any
other water.
If you think you have seen an
unusual shrimp, please email a photograph to
alert_nonnative@ceh.ac.uk for
identification.
