As invasive American Signal Crayfish numbers surge at a Derbyshire site, a bold rescue mission gives the UK’s White-clawed Crayfish a fighting chance – thanks to a new “Ark site” in Staffordshire.
The White-clawed Crayfish (Austropotamobius pallipes) is the UK’s only native crayfish species, and it is under serious threat.
Conservation efforts have intensified at a site in Derbyshire following a dramatic increase in invasive American Signal Crayfish (Pacifastacus leniusculus). The invasive species outcompetes and preys on White-clawed Crayfish, and also carries crayfish plague (Aphanomyces astaci) – a disease lethal to the native “White-claws” that can wipe out entire populations within weeks.
The rescue operation
A previous rescue operation successfully removed 60 native White-clawed Crayfish from the Derbyshire site. But when teams returned, they found the situation had worsened significantly.
During a follow-up visit in December, conservationists found “berried” females – crayfish carrying eggs – alongside three further American Signal Crayfish. The berried females were carefully transferred to Birmingham Sea Life Centre, where they were kept in quarantine and given thorough health checks.
Early in April there was a significant milestone: the successful release of these females, still carrying their eggs, to a specially chosen “Ark site” stream in Staffordshire.
A safe haven
The Ark site provides a protected environment, completely free from invasive species.
Before the release, house bricks with specially shaped cavities were placed in the brook to give the crayfish shelter. These mimic the natural refuges crayfish use to hide from predators, and the animals had already been accustomed to using them during their stay at the Sea Life Centre, making the transition as smooth as possible.
Liz Oldring, from Buglife and the Midlands Crayfish Partnership explained: “This is now a race against time. The rapid increase in American Signal Crayfish numbers shows just how quickly this invasive species can take over. Without intervention, the loss of this entire native population is inevitable. However, the establishment of the Ark site gives us real hope for the future.”
Natalie Emmerson, Assistant Curator at Sea Life Birmingham Centre added: “We are always delighted to be able to play our part, working with such a dedicated network of people for the conservation of a native species.”
In parallel with the Ark site release, a second team returned to the Derbyshire site and rescued a further 23 White-clawed Crayfish.
But the scale of the invasive threat has escalated sharply. The team recorded 17 American Signal Crayfish, including a berried female carrying several hundred eggs, highlighting just how rapidly this destructive species can reproduce and spread.
The additional 23 rescued “White-claws” have now been transferred to Birmingham Sea Life Centre for quarantine, where they will remain until they can be assessed and relocated to the same secure Ark site.
Kath Stapley, Living Rivers Officer at Derbyshire Wildlife Trust shared: “This site used to be a great stronghold for our native White-clawed Crayfish, but it is unfortunately now colonised by Signal Crayfish too and they are currently living side by side. However, this won’t be for long as the Signals will wipe the White-claws out. It’s so important that partner organisations work together to rescue as many of our native crayfish as possible and we have a great opportunity to do this, especially as we’ve been able to rescue females with eggs.”
A collaborative effort
Liz Oldring continued: “This has been a successful collaboration of landowners and partners, to whom we are extremely grateful, including Birmingham Sea Life Centre, Staffordshire Wildlife Trust, Derbyshire Wildlife Trust, AECOM, the Environment Agency and Buglife.
“We also wish to acknowledge and thank all the National Lottery players, as well as the National Lottery Heritage Fund, who have provided timely funding for this crucial project.”
The conservation programme continues to prioritise the rescue and relocation of as many White-clawed Crayfish as possible throughout the Midlands.