White clawed crayfish, which are native to the UK, are now seriously endangered, thanks to the spread of their cousins from across the pond – the much larger and more aggressive American signal crayfish pictured here. American signal crayfish not only drive out native white clawed crayfish as they compete for food and habitat, but also carry a water-borne fungus which is fatal to our native species. It is predicted that white clawed crayfish could become extinct in the UK within decades if efforts are not made to protect them.

The Environment Agency is running the first ever captive breeding programme for native crayfish, releasing the new crayfish into ark sites where they are safe from American signal crayfish