Species alerts

Quagga Mussel - Dreissena bugensis rostriformis

Quagga Mussel - <em>Dreissena bugensis rostriformis</em>

This is a species alert issued as part of the GB rapid response protocol:

The Quagga Mussel (Dreissena bugensis rostriformis) is a highly invasive non-native species from the Ponto-Caspian region, very similar to Zebra Mussel. It can significantly alter whole ecosystems by filtering out large quantities of nutrients and is also a serious biofouling risk blocking pipes smothering boat hulls and other structures.

Unlike Zebra Mussel this species has not yet been found in Great Britain, but based on its spread through Europe is expected to arrive soon. It is essential to identify any new invasion as early as possible.

Sightings should be reported online using this reporting form:


Or send an email with a photograph and location details to:

alertnonnative@ceh.ac.uk

Quagga Mussel resources:

[Image courtesy of Utah Division of Wildlife Resources]


Asian hornet - Vespa velutina

Asian hornet - <em>Vespa velutina</em>

This is a species alert issued as part of the GB rapid response protocol:

Vespa velutina, sometimes known as the 'Asian hornet’ is an invasive non-native species from Asia.  It has recently arrived in France where it is spreading rapidly.  As a highly effective predator of insects, including honey bees and other beneficial species, it can cause significant losses to bee colonies, other native species and potentially ecosystems.  

Not yet present in GB, but it is considered likely to arrive soon.  The places it is most likely to be found are in southern parts of England (it may be able to cross the channel from France) or goods among which it could be accidentally imported (such as soil with imported pot plants, cut flowers, fruit and timber).  Active months between April and November (peak August/September).  Inactive over the winter, so the most likely time to see this species will be early next year.

Sightings should be reported online using this reporting form:


Or send an email with a photograph and location details to

Do not under any circumstances disturb or provoke an active hornets’ nest.

Asian Hornet resources:

Guidance for bee keepers: can be found on BeeBase.

[Image courtesy of Jean Haxaire]


Killer shrimps - D. villosus and D. haemobaphes

Killer shrimps - <em>D. villosus and D. haemobaphes</em>

This is a species alert issued as part of the GB rapid response protocol:

Dikerogammarus villosus and Dikerogammarus haemobaphes, sometimes known as 'killer shrimps', are invasive non-native species that have spread from the Ponto-Caspian Region of Eastern Europe. They are both voracious predators that kill a range of native species, including young fish, and can significantly alter ecosystems.

D. villosos was originally found in Great Britain in 2010, while D. haemobaphes was found more recently in 2012.

Good biosecurity is essential to help slow the spread of these species.  You can learn more about biosecurity here:  Check, Clean, Dry

Sightings of either species should be reported to: alertnonnative@ceh.ac.uk

Briefing notes with the latest information about these species are provided below, along with additional resources such as ID guides and risk assessments.

Dikerogammarus haemobaphes

Briefing notes:

Additional resources for D. haemobaphes:


Dikerogammarus villosus

Briefing notes:

The D. villosus Task Group oversees and coordinates the response to this species in Great Britain. It has produced a position statement which summarises the rationale behind the response and is intended to help all stakeholders understand what we are currently collectively aiming to achieve.

Additional resources for D. villosus:


[Image courtesy of the Environment Agency]


Water Primrose - Ludwigia grandiflora

Water Primrose - <em>Ludwigia grandiflora</em>
This is a species alert issued as part of the GB rapid response protocol:

An invasive non-native plant from South America which has become a serious pest in other countries, including France, where it smothers water bodies reducing the numbers of native species and potentially increasing the risk of flooding.

It has started to be found in some parts of England and Wales.

If you think you've seen it, check with our Identification sheet.

Sightings should be reported:
Further information:

Carpet Sea-squirt - Didemnum vexillum

Carpet Sea-squirt - <em>Didemnum vexillum</em>

This is a species alert issued as part of the GB rapid response protocol:

Carpet Sea-squirt (Didemnum vexillum) is a highly invasive non-native marine animal that could threaten conservation, fishing and the shellfish industry.

Thought to be originally from Japan, it has become a pest in other countries by smothering native species and interfering with fishing, aquaculture and other activities.  It has recently been found in some marinas in England and Wales and there are strong concerns that it will spread more widely.

Use this webpage to report your sighting:

Or email:

alertnonnative@ceh.ac.uk

Further information:



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