A species of seaweed that occurs naturally in Japan and China has spread to Skye, according to a new report from the Scottish Natural Heritage.
The invasive species is called sargassum muticum, also known as wireweed. It is thought to have arrived in UK waters in the 1960s and was first recorded in the UK in 1973. The seaweed was first identified in Scottish waters in 2004.
A Scottish Natural Heritage report says it can now be found from the Firth of Clyde to Skye.
The spread of sargassum muticum is described as the "most noticeable change" to be picked up in the new report detailing a survey of marine biodiversity and climate change. It displaces native species through over-growing and starving them of sunlight.
The report said climate change "may facilitate" its further spread, but added that it could be able to extend its range without the aid of warmer temperatures.
Sargassum muticum can be spread via its spores being carried from one place to another in ships' ballast water, and by entire "rafts" of the plants floating to new locations.