We recently joined our conservation partners from Hampshire and Isle of Wight Wildlife Trust at their Winnall Moors Nature Reserve, one of the last refuges of the endangered white-clawed crayfish in Hampshire.
The white-clawed crayfish Austropotamobius pallipes is the UK’s only native species of crayfish, a type of crustacean which resembles a small lobster. Our native crayfish live in a wide range of freshwater habitats including streams, rivers, lakes and canals. They hide under stones and in small crevices and forage for insects, worms, snails, and plants.
As they require clean and well oxygenated water as well as minerals to fortify their exoskeleton, the presence of white-clawed crayfish indicates that an ecosystem is in good health. Chalk streams are an ideal habitat for them. The UK has 85% of the world’s chalk streams, many of which are found in Hampshire.
Photos: Our team joined Hampshire and Isle of Wight Wildlife Trust at Winnall Moors Nature Reserve.
In this idyllic riverside setting just outside of Winchester, we were delighted to find a total of fourteen feisty crayfish of both sexes and various ages. This is a very encouraging sign that the population is currently healthy. The introduction and spread of the invasive signal crayfish Pacifastacus leniusculus, and the disease ‘crayfish plague’ that it carries, has wiped our native species out from most of its natural range. With the added stresses of habitat loss, pollution and climate change, the surviving populations such as this one are still extremely vulnerable.
It’s only with robust insurance populations that we can ensure the long-term survival of the UK’s white-clawed crayfish. That is why we are working with Hampshire and Isle of Wight Wildlife Trust and Bristol Zoological Society to maintain a healthy crayfish population in captivity and create ‘ark sites’; crayfish safe havens where they are protected from crayfish plague and other threats.
Photos: Measuring a crayfish helps us to estimate its age.