Anglia Ruskin scientist to track voracious alien invaders

Published: 6 June 2011 at 11:21

Study will assess the effect of trapping on populations of signal crayfish

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An Anglia Ruskin University scientist is carrying out research into an “alien invader” that is causing destruction as it spreads through the UK.

The signal crayfish was introduced into the UK in the 1970s when farmers were encouraged to rear them as part of a farm-diversification initiative. However, a number escaped and there are now wild populations in over 87% of our river catchments.

These alien signal crayfish are causing serious damage to the UK’s ponds, rivers and canals, and out-compete our native white-clawed crayfish on every front, being ferocious predators of both plants and animals.

With large red claws and growing up to 30cm in length, the signal crayfish dwarf the white-clawed crayfish, which are usually less than 10cm long.  Signal crayfish are more fertile and faster growing than the white-clawed crayfish, and also carry crayfish plague (Aphanomyces astaci), which is a fungal disease fatal to the white-clawed crayfish but which signal crayfish are mostly resistant to.

Abby Stancliffe-Vaughan is researching signal crayfish in the Brecks, which spans Norfolk and Suffolk, and aims to discover whether trapping the invading crayfish has an effect on the size and sex ratios of their population.

Abby, of Anglia Ruskin’s Life Sciences Department, said:

“Signal crayfish are having a catastrophic impact on our indigenous white-clawed crayfish and the biodiversity of our rivers due to the erosion and siltation caused by their burrowing. 

“I’ve been studying areas where the signal crayfish are being trapped and comparing them to areas where there is currently no trapping. 

“Trapping is known to remove larger crayfish first but as these are the most reproductively active this could have a long-term effect in reducing their population.

“It’s really important that we understand more about the population structure of signal crayfish, especially the populations that have been trapped.  Tagging large numbers will help us to shed light on this important issue and it’s my intention to do just that this summer.”

Abby is looking for volunteers to help with her fieldwork, which will involve data recording, trapping, collecting and sexing crayfish.  For further information, contact Abby by emailing or phoning 07824 720405.