Nicky is researching the potential of male sterilisation as a control technique for signal crayfish at Bournemouth University, supervised by Professor Rob Britton and Dr Paul Stebbing of CEFAS. The research is based on field studies (including the River Barle) and laboratory work. Lab studies to date have found that sterilised males are equally capable of becoming dominant and competing for food, mates and shelter as non-sterilised males. Females are as likely to choose to mate with a sterilised males as a non-sterilised male.
River Barle Signal Crayfish Project
This project is a volunteer led signal crayfish control project on the River Barle Site of Special Scientific Interest. It started in 2015 and consists of intensive trapping combined with the sterilisation and return of large males which dominate breeding behaviour. The project is innovative in that it has never been trialled in the field in the UK and has attracted interest from practioners from all over the country. So far over 12,000 crayfish have been removed and 2000 large males sterilised and returned to the river. Reduced berried (egg bearing) female numbers and changes to population structure are evidence that the procedure is working. The Exmoor Non-Native Invasive Species (ENNIS) Project, launched in April 2019, is supporting the continuation of this project in addition to studies of other signal crayfish populations on Exmoor.
Culm Community Crayfish Project
The Culm Community Project in 2018 was funded by the Heritage Lottery Fund and the East Devon Catchment Partnership and managed by the Blackdown Hills AONB. It aimed to raise awareness of river health using crayfish as a flagship species via a crayfish surveys, environmental education, practical works and community engagement. Nicky trained 48 volunteers and supervised the survey of 27km of the river Culm. The project also engaged over 1700 and 45 teachers, delivered 11 community events and attended local events such as Devon County Show. The crayfish data gathered in 2018 is now being used to attract funding for future white-clawed crayfish monitoring and ark site projects on the River Culm.
Signal Crayfish Control Trials
In 2019 Nicky is setting up short term signal crayfish control trials in two ponds within the River Culm catchment with the help of local volunteers. The first stage is assessment of the crayfish populations, opportunities and constraints prior to deciding on the most feasible combination of methods for each site. The work is funded by the Environment Agency’s Water Environment Grant.
Nicky, with client South West Water and expert colleagues Tim Clements and Phil Short, has been developing a dive survey technique to determine crayfish presence in large waterbodies such as reservoirs. Crayfish are often difficult to locate and quantify impossible to locate from shore based surveys as they prefer deeper waters not accessed by conventional surveys.
Conservation and Monitoring
Nicky has been involved in the monitoring of Devon’s remaining white-clawed crayfish populations with the local Environment Agency since 2003. Unfortunately both populations are threatened by invading signal crayfish and translocations to suitable ‘Ark Sites’ were carried out in 2012 and 2013. This project was part of the South West Crayfish Project which was set up by a partnership of Buglife, the Environment Agency, Bristol Zoo and the Avon Wildlife Trust.