A population count of the migratory birds in November 2020 found 43,703 wintering in Dumfries and Galloway, however this month it was found that figure had dwindled to 27,133 – a decline of 38 per cent.
This has prompted RSPB Scotland to call for an emergency local moratorium restricting shooting on the Solway for the rest of the wildfowling season.
The barnacle goose is a protected species and is not hunted.
However, pressure from wildfowlers hunting other legal quarry species centers on the disturbance caused to nearby barnacle geese, making flocks take to the air, using up energy and potentially increasing stress.
Paul Walton, head of Habitats and Species at RSPB Scotland, said: “We are in the grip of an unprecedented outbreak and unfortunately the Solway seems to be the epicenter of this in the UK.
"Our birds are suffering and they need an urgent reprieve to help them get through this winter and ensure as many as possible survive to make their migration back home.
“The best way we can do this is by reducing the cumulative impacts of disturbance, including by wildfowling.
"Our teams on the ground are seeing many birds that are sick or dying and under significant stress.
"Anything that can be done to limit activities which incur additional disturbance at this time should be implemented with urgency.“