THE CHINESE MITTEN CRAB  Eriocheir sinensis

An exotic addition to Yorkshire’s aquatic fauna.

ORIGINS

A native of China, this impressive beast, which spends much of its life in brackish and fresh water, is thought to have been transported to Europe in ballast tanks of shipping. It was first noticed in Germany in 1922 and is now well established in several of the continental river systems which discharge into the Baltic and southern North Sea (Fryer 1993).

1st YORKSHIRE RECORD

In 1949 a young angler from Castleford caught a mitten crab in Southfield Reservoir, a compensation reservoir for the adjacent Aire/Calder Navigation nr. Thorne (SE/6518). The animal was trans-located to a ‘fenced off’ section of a stream near Hollywell Wood, Glasshoughton but disappeared a few days later (Limbert & Wall 1983).

RECENT YORKSHIRE and HUMBER CATCHMENT RECORDS

In 1976 and 1979 specimens were found in eel nets on the south Humber shoreline near the River Ancholme outlet (SE/9721) and in 1984 one was actually located in the Ancholme itself (Clark 1984). In 1984 unconfirmed anecdotal evidence came from eel nets-men working the Blacktoft-Faxfleet area of the estuarine Ouse/Humber confluence (SE/82) (Mel. Todd pers. comm.1984). In 1986 one was found further up the tidal Ouse at Cawood (SE/5738) and in September 1991 ‘a colony’ was found in the River Wharfe (presumably the lower reaches) (Fryer 1993).

On 1st October 1995 one was caught on rod and line in the New Junction Canal, Kirk Bramwith, Doncaster (SE/6111). After being examined by Environment Agency biologists it was donated to Doncaster Museum by Chris Firth (EA Fisheries Officer) (Accession no. DONMG ZZ.267). This specimen was exhibited at the YNU Conference on the ‘Freshwater Ecology of Yorkshire’ (March 2001).

The results of a new study undertaken by Dr Matt Bentley and a team of co-workers at the University of Newcastle monitored spread in British waters included a record from the Tees (NZ/52) in 2001

(See:http://www.practicalfishkeeping.co.uk/pfk/pages/item.php?news=837). 

Doncaster records in 2008

In July 2008 one was caught on rod and line in the Don at Barnby Dun (SE/6009) by a local angler (Tony Bryan Pers comm. 2008).

Angler, Steve Smith caught one on rod & line in the Trent at Besthorpe (SK/8265) on 26th July 2008, his report reading “I did an overnighter yesterday on the Trent at Besthorpe and hooked what I can only describe as a crabs claw, its got fur near the pincers and a spike near the joint.  I’ve shown it to two other anglers that were present and they said I should inform the EA. Has anybody heard of mittens on the Trent?” (http://www.fishingmagic.com/forum).

On 17th September 2008 an adult (Carapace width 7cm, Carapace length 6cm and legspan of 30cm) was caught on rod and line, using ‘Monster Crab’ boilies (!) as bait in the Don at St Mary’s Bridge in the heart of Doncaster (SE/569039) by a local angler Keith Montgomery (Doncaster Free Press 2008, South Yorkshire Times 2008) (see photos by Pip Seccombe).

Within the period (15th to 18th Sept.) the Environment Agency (Leeds) received a further four reports: One caught in the lower Aire at Hirst Courtney (SE/6123), two crabs caught in the River Idle near Westwoodside (SK/7395) and one caught in the River Went near Sykehouse (SE/6318) (pers. com. Amanda Best EA). It seems likely that this sudden speight of records in tidal tributaries of the Humber, represents a sudden seasonal migration down to brackish waters in the lower Humber estuary for spawning purposes.

OTHER BRITISH RECORDS

It was first identified in British waters in 1935 in the Thames system where it has now been recorded at West Thurrock Power Station, the Regent’s Canal Dock and at Teddington Lock (Clark 1984). In northern Britain it appeared in the Air/Calder Navigation system in 1949 and the Humber system in 1976 (see above) and was noticed in the Tyne estuary  in 2001 (Wilkinson 2001).

Although spending much of its life in fresh water, it returns to the sea to breed. Its larval stages are therefore able to spread bet ween estuary systems via tidal and in-shore current systems (Wilkinson 2001). Interestingly, the only British evidence of this is from Dave Whittaker’s superb Yorkshire Coast Sealife, Fisheries & Maritime Archive website, founded in 1969 http://yorkshirecoastmaritimearchive.co.uk/. This  website gives important records and photographs of Chinese Mitton crabs being found on the Holderness coast, a British first. This website is highly recommended.

Although this large crab burrows into river and canal banks, to date no significant structural damage to flood defences has been reported in the Humber region. River engineers in the Environment Agency or British Waterways in our region fear that populations could potentially pose problems of this nature and welcome any records of spread or population build-ups.

ACKNOWLEDGEMENTS

Thanks are due to Keith Montgomery and Tony Bryan. Amanda Best and Jerome Masters of the Environment Agency, Leeds for records from the rivers Went, Idle and Aire.

Photos are by Pip Seccombe of Doncaster Naturalists Society

REFERENCES

Clark, P. (1984) Recent records of alien crabs in Britain. Naturalist 109: 111-112.

Doncaster Free Press (2008) 25 September 2008

Fryer, G. (1993) The Freshwater Crustacea of Yorkshire. Leeds. YNU and Leeds Phil. & Lit. Soc.

Howes, C. A. (2003) The Chinese Mitten Crab (Eriocheir sinensis Milne-Edwards.): An exotic addition to Yorkshire’s aquatic. Proceedings of the Conference on The Freshwater Ecology of Yorkshire. YNU Bulletin (Suppl.) 40: 87-88.

Wall, C. and Limbert, M. (1983) A Yorkshire record of the Chinese Mitten Crab. Naturalist 108: 147.

Wilkinson, P. (2001) The Times 17th February 2001.

South Yorkshire Times (2008) 25 September 2008

C. A. Howes

7 Aldcliffe Crescent, Balby, Doncaster DN4 9DS

Tel: 01302 811571

Email: colinhowes@blueyonder.co.uk