Crayfish Ark Site Establishment at Fernhill Farm

 The white-clawed crayfish (Austropotambius pallipes) is the UK’s only native freshwater crayfish species that is endangered throughout its range in both the UK and Europe due to pollution, habitat degradation and the threat of invasive crayfish species.  Crayfish ark site establishment is a proven conservation measure where safe sites are set up to help conserve this species.  Bristol Zoological Society breeds and rears white-clawed crayfish, for both ark sites and outreach combining this programme with scientific research.  Before a site can be selected several surveys are undertaken to assess the habitat, water quality and species that are already present, to see if it might be suitable for crayfish. This process can take a couple of years! 

Wetland Ecosystem Treatment (WET) systems can act as effective wetland nature reserves and can quickly establish healthy aquatic ecosystems, to enhance and improve biodiversity whilst providing many native species with an important water source.  Here at Fernhill, we have set up the WET system as a white-clawed crayfish ark site.  The lowest tier of the Fernhill WET system is approximately 0.5 acres (2000m2) with a varying depth of 0.2-1.5m and has superb water quality and impressive biodiversity, which can support this sensitive crayfish species.  Over the past five years we have added over 300 captive-born white-clawed crayfish and we are hoping that they will thrive and reproduce up here in the Mendip Hills.