Nicky has been manufacturing and selling ARTs since 2006 and clients include the Environment Agency, Bristol Zoo, Dorset Wildlife Trust, Peak District National Park and the Westcountry Rivers Trust. The design has been refined over the years to make the trap robust, hard wearing, lightweight and cost effective. They are designed to catch a wide range of size classes of both native and non-native crayfish.
Artificial Refuge Traps (ARTs) mimic the natural refuges that crayfish utilise in the wild. Technically they are not a ‘trap’ as the animals can escape at any time but they still need consent from the Environment Agency. ART’s have several advantages over conventional ‘Trappy’ style baited traps: –
- Baited traps tend to be biased towards large adults, particularly males. Removal trapping using this method often fails to reduce crayfish numbers as the loss of dominant males reduces competition, allowing smaller males to mature and mate and increasing their survival, growth and dispersal rates. ARTs are not biased and have been found to catch a wide range of crayfish sizes, from 5mm (young of year) to 65mm (5+ years).
- Baited traps can sometimes catch non-target species such as otters and water-voles. Because ARTs are not a ‘trap’ there is no risk to non-target species.
- Because conventional baited traps are enclosed they must be checked at least once every 24 hours. ARTs can be left in situ for a period of weeks or even months between checks which makes their use very cost-effective.
- Baited traps are often ineffective in river situations, especially when monitoring low density native crayfish populations. Nicky has used ARTs since 2006 and found them to be far more effective than baited traps at recording white-clawed crayfish on Devon rivers where they are at low density. The Exmoor crayfish project uses both types of trap and again ARTs are found to catch far greater numbers of crayfish than baited traps.
Nicky and colleagues have written a paper comparing ART’s to funnel traps which can be viewed here: –
https://www.kmae-journal.org/articles/kmae/abs/2018/01/kmae170112/kmae170112.html They found that ARTs caught 87% of total crayfish, 95% of berried females and 89% of moulting individuals with an equal sex ratio and far wider size range than funnel traps.
For more information on ARTs click here