A new Native Species Zone has officially opened at Marwell Zoo, marking a significant step in efforts to safeguard the endangered white-clawed crayfish Austropotamobius pallipes – Britain's only native crayfish.  

Developed in partnership with Hampshire & Isle of Wight Wildlife Trust and Bristol Zoological Society, the Zone includes a dedicated white-clawed crayfish Breeding Centre. Breeding and rearing animals at Marwell Zoo will play a crucial role in the Trust’s Southern Chalkstreams Project, an initiative which protects and restores these fragile freshwater ecosystems, with a focus on the endangered white-clawed crayfish. 

White-clawed crayfish were once widespread and common throughout England and Wales, but since the 1970s they have suffered a dramatic decline, reflecting the 50-80% decline seen across its global range. The alarming loss of this species across the UK is primarily due to competition and predation from a larger invasive non-native crayfish species, the signal crayfish Pacifastacus leniusculus from North America, which also carries a deadly crayfish plague which can quickly wipe out our native species.  

The new centre will help strengthen the status of white-clawed crayfish in the wild. It will provide a biosecure environment where the crayfish can be reared before being released into protected ark sites in Hampshire, establishing new populations of the species. These specially monitored locations provide a safe haven where they can thrive.  

Furthermore, it is intended that crayfish will be released within the river catchments from which their parents were collected, increasing the strength or resilience of our existing populations in Hampshire. 

Dr Ben Rushbrook, Principal Ecologist at Hampshire & Isle of Wight Wildlife Trusts said: “The opening of this new Breeding Centre is an incredibly exciting moment for white-clawed crayfish in Hampshire. It represents a major milestone in helping to protect and restore our wild populations, and the culmination of nearly two years of hard work by staff at Marwell Zoo, the Trust, and Bristol Zoological Society.  

“Through the Southern Chalkstreams Project, we’re not just saving a species, we’re restoring balance to our rivers. By taking action now, we can ensure these wonderful native crustaceans continue to thrive in our rivers for generations to come, helping to safeguard the rich biodiversity – and incredible wildlife - of our chalk streams." 

Hampshire is home to many of England’s globally rare chalk streams, with 85% of the world’s chalk streams found in the UK. As a keystone species, white-clawed crayfish play a vital role in maintaining the health of these freshwater ecosystems.  

Ben adds: "White-clawed crayfish are truly remarkable. They are not only fascinating and secretive, but as one of our largest native freshwater invertebrates, they also help shape the ecology of those chalks rivers where it still exists.” 

The new centre builds on more than a decade of conservation work carried out by Hampshire & Isle of Wight Wildlife Trust in partnership with Bristol Zoological Society, which has been rearing white-clawed crayfish of Hampshire origin at its hatchery since 2013. Since then, nearly 2,000 of these captive born white-clawed crayfish have been released into the wild. 

It also complements the Trust’s partnership work with the Wildheart Trust on the Isle of Wight, who established a Crayfish Conservation Centre at their Wildheart Animal Sanctuary site in 2024.  

Dr Jen Nightingale, UK Conservation Manager from Bristol Zoological Society, said: “I am delighted that we now have a crayfish hatchery in Hampshire. Marwell Zoo will be able to house berried (egg-carrying) white-clawed crayfish for hatching and rearing of juveniles. In captivity, we can achieve much higher survival rates of the young which can then be released into safe ark sites in the future, helping to build resilience and safeguard white-clawed crayfish populations in Hampshire”. 

Marwell Zoo’s new Native Species Zone, which also features sand lizards, will provide visitors with a rare opportunity to see white-clawed crayfish up close and learn about the threats facing vulnerable UK wildlife. The new area aims to raise awareness of conservation challenges and inspire the public to take action in protecting native species. 

Laura Read, Chief Executive of Marwell Wildlife, said: “Marwell has a proud history of native species conservation, and the opening of the first white-clawed crayfish breeding centre in Hampshire marks an exciting new chapter in our efforts to protect UK wildlife.  This new space not only strengthens our role in safeguarding endangered native species but also allows our guests to experience and engage with our conservation work firsthand. For the first time, guests can explore a dedicated area of the zoo that highlights our commitment to restoring local biodiversity and inspiring action for nature." 

Marwell’s Native Species Zone has been made possible thanks to funding from the UK Government’s Rural England Prosperity Fund, Winchester City Council, donations from the Big Give Green Match Fund and support from generous donors. 

For more information on the Southern Chalkstreams Project and efforts to save white-clawed crayfish, visit: www.hiwwt.org.uk/southern-chalkstreams