Wakame - Invasive Species Information
Reproduction: prolific spore production and its ability to foul structures both in its macroscopic and microscopic forms. It spreads rapidly and geographically distant populations can appear in a short space of time. It is transported to new areas by human activities in both its highly visible sporophyte, or as the microscopic gametophyte and spore stages in its life cycle.
Wakame stand
Wakame or Japanese seaweed, is a highly invasive seaweed that can grow to 3m in length and has green-brown fronds. It grows in sheltered temperate waters, forming dense forests at depths of up to 15m and can quickly displace native habitats.
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This seaweed is green and golden-brown in colour with a lighter coloured stem and a branched holdfast (for attachment to the substrate). The stipe has very wavy edges, giving it a ridged appearance. Undaria has a broad, attened leaf shaped blade with a distinct midrib and wavy margins.
How To Identify Wakame?
Colour: Green-brown fonds can grow up to 1-3m tall
Leaves: stop short of base, Midrib up to 3cm wide with frilly base Hold fast
Wakame - Undaria pinnatifida ID Guide
Wakame leaves
Wakame stand
Why Is Wakame A Problem?
Can be highly invasive and grow rapidly into dense beds
Overgrows and excludes native algal species preventing biodiversity and altering marine food chain. as an opportunistic species, takes advantage of areas disturbed by human activities or grazing by herbivores such as urchins and is also known to grow in areas not normally occupied by native seaweeds where it may have a high degree of impact.
What Is Wakame - (Undaria pinnatifida)?
Habitat: Aquatic. Costal areas.
Distribution in Ireland: Present around coastal waters
Status: Established
Family name: Alariaceae
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European Communities (Birds and Natural Habitats) Regulations 2011 non-native invasive plant species A-Z (Updated 2017)
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There are currently 35 invasive plant species listed in the European Communities (Birds and Natural Habitats) Regulations (annex 2, Part 1)...
Click on a species from the following list to find out more regarding non-native species subject to restrictions under Regulations 49 and 50.
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American Skunk-Cabbage - Lysichiton americanus
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Brazilian Giant-Rhubarb - Gunnera manicata
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Broad-Leaved Rush - Juncus planifolius
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Cape Pondweed - Aponogeton distachyos
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Cord-Grasses - Spartina (all species and hybrids)
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Curly Waterweed - Lagarosiphon major
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Dwarf Eel-Grass - Zostera japonica
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Fanwort - Cabomba caroliniana
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Floating Pennywort - Hydrocotyle ranunculoides
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Fringed Water-Lily - Nymphoides peltata
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Giant Hogweed - Heracleum mantegazzianum
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Giant Knotweed - Fallopia sachalinensis
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Giant-Rhubarb - Gunnera tinctoria
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Giant Salvinia - Salvinia molesta
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Himalayan Balsam - Impatiens glandulifera
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Himalayan Knotweed - Persicaria wallichii
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Hottentot-Fig - Carpobrotus edulis
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Japanese Knotweed - Fallopia japonica
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Large-Flowered Waterweed - Egeria densa
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Mile-a-Minute Weed - Persicaria perfoliata
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New Zealand Pigmyweed - Crassula helmsii
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Parrots Feather - Myriophyllum aquaticum
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Red Alga - Grateloupia doryphora
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Rhododendron - Rhododendron ponticum
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Salmonberry - Rubus spectabilis
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Sea-Buckthorn - Hippophae rhamnoides
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Spanish Bluebell - Hyacinthoides hispanica
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Three-Cornered Leek - Allium triquetrum
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Wakame - Undaria pinnatifida
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Water Chestnut - Trapa natans
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Water Fern - Azolla filiculoides
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Water Lettuce - Pistia stratiotes
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Water-Primrose - Ludwigia (all species)
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Waterweeds - Elodea (all species)
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Wireweed - Sargassum muticum