About | Mitten Crab Watch

Add a record

If you see a mitten crab, a sighting report requires:
- a clear photograph of the individual
- the number of crabs seen
- the exact location, time and date of the sighting

If you have the iNaturalist app (available on iOS and
Android), a useful tool to record any wildlife sightings both in the UK and overseas, you can submit the record directly on the app or via the iNaturalistUK website.

You can download a Mitten Crab ID guide from NNSS here.

You can also upload records to iRecord, which like iNaturalistUK, shares the data with the NBN Atlas, a national biodiversity database.

Alternatively, you can email the Marine Biological Association through dassh.enquiries@mba.ac.uk with your photograph, location, time and date of the sighting and they can record the sighting for you.

About

Chinese mitten crabs are officially listed as one of the World's 100 worst invasive species. They can cause damage to fishing gear and river banks, block intake screens, modify natural habitats and compete with native species. It is this economic and ecological damage that makes this crab such an unwelcome arrival. The full extent of these exotic pests in English and Welsh waters is currently unclear and a consortium of research institutes is requesting mitten crab sightings from members of the public, anglers and waterway workers, to clarify the distribution of this species.

Find out more

Philine zu Ermgassen, Freshwater Ecologist at the University of Cambridge, talks about the identification, impacts and management of The Chinese Mitten Crab in Great Britain.