Crayfish find refuge in Devon's new 'ark'.
17th Oct 2025
Britain’s only native crayfish moved two-by-two into safety as Wildwood Trust fights extinction.
The specially created pond “ark site” at Wildwood Devon, part of one the charity’s pioneering conservation programmes, will provide a secure home where the species can survive and thrive away from invasive rivals and deadly disease.
Thirty-seven adult white-clawed crayfish - seventeen females and twenty males - have now been moved into the ark site.
A major milestone
Pete Burgess, Director of Conservation and Rewilding at Wildwood Trust, says it marks a major milestone for the project:
“Our new ark site provides a safe haven for white-clawed crayfish, free from the constant threats of invasive species and disease. This purpose-built refuge is completely isolated from rivers where non-native crayfish are found, creating the best possible conditions for their survival.
By relocating adults here, we are giving them the strongest chance to establish secure, thriving populations. The white-clawed is Britain’s only native species of crayfish, and without decisive action like this, it could disappear from our rivers forever.”
Wildwood's mission
Once-thriving populations of white-clawed crayfish in the South West have declined by up to 80%. Habitat loss, poor water quality, and the spread of invasive American signal crayfish - carriers of the deadly crayfish plague - have pushed the species to the brink. Their disappearance is more than just a loss of wildlife: as a keystone species, crayfish help keep rivers healthy by cleaning waterways, recycling nutrients, and supporting countless other species.
As part of Wildwood Devon’s mission to reverse this decline through its rescue, breed, and release strategy, teams carefully survey rivers such as the Culm and Creedy Yeo to locate and rescue surviving individuals. These are then transferred to a specialist hatchery, arranged into the breeding groups and the young then further reared in custom-built tanks. In 2024 alone, successful mating was recorded in 61 crayfish from the Rivers Culm and Creedy. Over 1000 juveniles have hatched from Devon and over 100 juveniles from Somerset.
Since 2023, Wildwood has operated a state-of-the-art crayfish hatchery and nursery, made possible through the support of the Environment Agency, Devon Environment Foundation, Natural England, the National Lottery Heritage Fund, and South West Water.
A dedicated ark site, funded by Natural England, with support from the Blackdown Hills National Landscape and South West Water, further strengthens the project’s conservation impact.
After the release
Dr Jen Nightingale, Crayfish Specialist, explains what will happen to the released crayfish;
“The animals that have gone into the Wildwood ark site have already bred once in the hatchery. We expect they’ll have at least one more cycle before they are too old for breeding. We will continue to stock the pond with additional animals both wild-caught and captive-born at the hatchery here. It’ll be their juveniles we use for this pond. Those young produced in the ark site can then be moved to safe ‘ark’ sites around Devon - places where we can reintroduce them and build a sustainable population.
They won’t return to their original catchment because it now has signal crayfish, so this has become a rescue project. Instead, their offspring will go into isolated coastal streams - ideal ark sites because they’re not connected to larger catchments and should stay free of signal crayfish.
It’s wonderful to see these crayfish being released into a natural site with perfect water quality and a thriving balance of invertebrates and plants - a place where they can truly thrive.”
What the future holds
One of the key stages in preparing the ark site for release involved ensuring that environmental conditions were perfect for crayfish. Temperature and water quality were monitored weekly. The site experienced higher-than-ideal temperatures during the hot, dry summer, although water levels remained stable. To mitigate elevated temperatures, shade covers were installed over the water until the growth of water lilies could provide sufficient natural shade.
Although the released crayfish will not be visible to the public, new individuals will be introduced to the display in future. Samiya Roache is Crayfish Hatchery Officer at Wildwood Devon;
“It’s really exciting to be doing our first release - this is what we’ve been working towards for the past two years. Although we will miss the adults we have released, especially the display ones, since we’ve grown quite attached to them, it’s fantastic to see them released into the ark site and their offspring destined for a long and healthy future in the wild. It is also exciting that we can now introduce new crayfish at a different life stage to the display for everyone to come and see.”
Photo credits: Harding-Lee Media and Marcus Brown