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Wireweed, Sargassum muticum


Short description of Sargassum muticum, Wireweed

Highly distinctive large olive-brown seaweed (often over 1m long). The tough, wiry stem has regularly alternating branches with small, flattened oval blades and spherical gas bladders. Lateral branches hang like washing from a line when held out of the water.

Description of Sargassum muticum, Wireweed status in GB

Wireweed is present at suitable habitats along the south and west coasts of England, Wales and Scotland.

Habitat summary: Sargassum muticum, Wireweed

Grows on hard surfaces in shallow waters and intertidally, particularly in rockpools. The species can also tolerate estuarine conditions. It can become detached and found floating in the sea.

Overview table

Environment: Marine
Species status: Non-Native
Native range: Northwestern Pacific
Functional type: Algae (macroalgae)
Status in England: Non-Native
Status in Scotland: Non-Native
Status in Wales: Non-Native
Location of first record: Bembridge, Isle of Wight.
Date of first record: 1971

Distribution map

Map of the UK with areas shaded to show the UK distribution of Wireweed

GB Distribution from NBN Atlas

Author's name:

Jack Sewell

Last updated:

October 3rd 2019

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Thin strip of image show tree trunk and bark