First UK reports of the Chinese mitten crab, Eriocheir sinensis
1935 - A single specimen was captured at Lots Road power station, situated on the River Thames.
1949 - A second specimen was found in Southfields Reservoir near Castleford, Yorkshire. This reservoir tops up the canal system and it is likely that the crab was introduced through shipping on the Humber River.
1973 - Three further specimens were collected from the River Thames at West Thurrock power station.
It isn't known why Britain didn't experience the same population explosion that swept through Europe in the 1930s.
River Thames spread
The population of mitten crabs in the Thames continues to increase, and records from both Europe and China have shown that the entire Thames catchment is at risk of invasion. So far:
- The species is known to have spread up the River Thames as far as Staines, 63km from the sea.
- Specimens have been reported from most rivers eastwards of Staines entering the Thames.
- The most northerly record is from Enfield.
Map showing the distribution of mitten crabs reported in the Thames catchment from 27 August to 15 November 1996 PDF (83.7 KB)
Map showing the distribution of mitten crabs in the UK (dots indicate recorded sightings). © Crown copyright, Defra (MB0102)
- Mitten crabs are common in the River Medway.
- There have been isolated captures from the River Tyne (Newcastle) and the River Tamar (near Exmouth).
- An egg-bearing female was recently captured from Dungeness, Kent.
- 2006 - Mitten crabs were reported from the River Dee Estuary on the Welsh border.
- To date there are no records of mitten crabs from Scotland.
- 2006 - A single male was collected from Waterford Harbour on the Suir Estuary at Bellview.