A worrying surge in American mink is threatening native wildlife along the Caledonian Canal and River Ness.

The non-native creatures are causing havoc and the rise in numbers has sparked calls for volunteers to help eradicate them.

A major four-year project, led by Scottish Natural Heritage, is underway to trap the “opportunistic predator”, which have spread following escapes from fur farms in the latter half of the last century.

Chris Conroy, director of the Ness District Salmon Fishery Board, said: “We’re aware of an increase in the number of sightings of these invasive non-native animals in our area which is worrying.

“They are known to predation upon our native ground-nesting birds, water voles and fish. The rocky nature of the canal embankments and the banks of the River Ness provide perfect habitat for the American mink.

“They can move around between these rocks underground without being detected. Sightings peaked last month when the young mink disperse from their mothers and become more visible.”