The seaweed is a threat to native marine life

Japweed is a fast growing weed with fronds that can reach eight metres long and have the potential to smother native seaweed and other marine plants.

It is the first time Japweed, which is native to Japan, has been found in Scotland and conservationists say it is almost impossible to get rid of.

There are fears that the weed could colonise and smother commercial oyster and mussel beds.

Scottish Natural Heritage (SNH) fears that Japweed or wire weed (Sargassum muticum) could cause "commercial and environmental damage".

SNH's Andrew Bielinski said: "Even the fronds when they are floating around are actually capable of reproduction, so it's quite a vigorous species.

"We think that it could end up smothering out some of the more important seaweed species in Loch Ryan which make this place particularly special in a Scottish context."

It is thought the weed has been spreading around the world on the hulls of ships.

It probably got into Loch Ryan on the ferries from Northern Ireland where it turned up some time ago.