Posted on 12/09/2011
Phil Crabb, NHM Photo Unit
Scientists from a consortium of UK research institutes, including Royal Holloway, University of London and the Natural History Museum (NHM), are asking the public to help record sightings of the Chinese mitten crab to better understand the full extent of their invasion and the threat these crustaceans pose to our rivers and waterways.
Members of the public can use an online survey to identify and record any sightings of the alien species. The recordings will be used by scientists to clarify the full distribution of the exotic crabs in English and Welsh rivers. The project is part of an ongoing collaboration between Dr David Morritt, and students from the School of Biological Sciences at Royal Holloway, with Dr Paul Clark at the NHM. This has included monitoring the autumn seaward migration of adult Chinese mitten crabs at the Thames Water site at Walton-on-Thames over the past four years.
Mitten crabs spend a number of years in the upper reaches of the Thames but have to return to the estuary to breed and release their larvae which then develop through a series of planktonic stages prior to settling on the seabed as juvenile crabs. These young crabs then migrate back up the Thames where they can cause significant damage to river banks and fishing gear as well as having an impact on native wildlife and fisheries.
Dr Morritt said: “Members of the public can really make a big difference by helping us to record any sightings of these crabs. By understanding more about the location of these intruders we can establish the extent of the invasion and the size of the problem.”
The general public can report their finds by phone, email or online and upload their photographs by visiting the project website or more information can be downloaded here.