Species	Distribution
Wireweed (Sargassum muticum) Photo courtesy of SNH	To view NBN location data click here
Impacts	Pathways
Rapid growth rate of up to 10 cm per day, with a long life span of 3-4 years. Reproduces both sexually and via floating fragments. Sexual reproduction releases thousands of "germlings" that settle rapidly. Dense monospecific mats can form very quickly excluding other species. Mats reduce available light for understory species, dampen water flow, increase sedimentation rates and reduce ambient nutrient concentrations available for native species.	Natural dispersal. Contaminant of oyster spat. Fouling on boats and other marine equipment.
Management
Prevention Has already been found in a number of sites in Scotland with rapid spread recorded in 2008 making prevention difficult. Physical Control According to the NNSS factsheet, it may be possible to physically remove individuals from localised areas by hand. Although care must be taken to prevent further spread of the species by detaching and spreading new, fertile sections. It is essential to remove the entire holdfast to prevent new growth. Recolonisation from surrounding populations following clearance is likely. Chemical Control None known Biological Control None known
Links
Non Native Species Secretariat identification guide Non Native Species Secretariat Fact Sheet SNH Species Action Framework Invasive Species Ireland Fact Sheet Daisie Species Fact Sheet Global Invasive Species Database