River, a little black spaniel in a bright orange vest is searching river bank in a Hampshire nature reserve. On this occasion, it's a demonstration only.

River is unique: the only conservation dog in the UK trained to find signal crayfish (Pacifastacus leniusculus), an American invasive species that was farmed as a delicacy in the UK in the 1960s and escaped into the wild.

The signal crayfish is a well equipped predator and will eat vegetation, small invertebrates and fish, including junior native crayfish. If they're hungry, they will turn on each other. They grow up to 18cm and burrow up to two metres deep into waterway banks, damaging habitat and leaving canals vulnerable to collapse. 

As if this weren't enough, they also carry "crayfish plague", a fungal disease, which is fatal to the UK's  native white-clawed crayfish. The native crayfish has declined drastically to the point of extinction. (The situation is akin to that of the invasive grey and native red squirrel).

River's handler, Lucy Wilde explains to Dogs with Jobs presenter, Kate Fairweather, how River has ended up with this specialised role, and what her working life looks like.

Other conservation dog episodes: 

• Reid, the bio security dog - update a year on
• Reid the bio security dog - the original interview;
• Skye, the stoat detection dog working to keep Orkney free from predators;
• A team of five detection dogs survey the Isle of May for ground nesting storm petrels;
• Barley the conservation dog and his international projects;
• Nica, Nettle and Phoenix, the Japanese knotweed detection dogs

Do you work your dog or dogs? 

Get in touch with Kate at team@shineradio.uk with suggestions or introductions to working dogs to feature on the show - she's always interested to hear about dogs with interesting jobs.

© & ℗ Kate Fairweather 2026