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Red Alga Invasive Species Information

High Risk

What Is Red Alga - (Grateloupia doryphora)?

Habitat: prefers to live in shallow, protected subtidal waters, and likes to attach itself to hard substrates. It can survive water temperatures between 4 and 28° C, and salinities between 12 and 52 parts per thousand. 
Distribution in Ireland: Coastal Areas 

Status: Unknown
Family name: Grateloupia

Reproduction: Spores develop giving rise to filaments and blades.

Red Alga - Grateloupia doryphora

Red Alga - Grateloupia doryphora

Red Alga leaves

How To Identify Red Alga?

Colour: Red, olive green, brown

Size: The ribbon-like blades of this seaweed can reach a size of 100 cm by 20 cm, but are usually much smaller.

Red alga prefers shallow, protected subtidal waters attaching itself to hard substrates.

Red Alga - grateloupia doryphora ID Guide

Red Alga - Grateloupia doryphora ID Guide

Why Is Red Alga A Problem?

Where Red Aga co-exists, it usually out competes the other non-native species.

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It can invade the habitat of a native seaweed, Chondrus crispus, aka: "Irish Moss", and crowd it out. Irish moss is used commercially to manufacture carigeen, and also provides an important winter food source for local marine invertebrates.

 

Additionally, the long blades of Red Alga can shade out other local species of algae and prevent them from growing nearby. 

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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  1. American Skunk-Cabbage - Lysichiton americanus

  2. Brazilian Giant-Rhubarb - Gunnera manicata

  3. Broad-Leaved Rush - Juncus planifolius

  4. Cape Pondweed - Aponogeton distachyos

  5. Cord-Grasses - Spartina (all species and hybrids)

  6. Curly Waterweed - Lagarosiphon major

  7. Dwarf Eel-Grass - Zostera japonica

  8. Fanwort - Cabomba caroliniana

  9. Floating Pennywort - Hydrocotyle ranunculoides

  10. Fringed Water-Lily - Nymphoides peltata

  11. Giant Hogweed - Heracleum mantegazzianum

  12. Giant Knotweed - Fallopia sachalinensis

  13. Giant-Rhubarb - Gunnera tinctoria

  14. Giant Salvinia - Salvinia molesta

  15. Himalayan Balsam - Impatiens glandulifera

  16. Himalayan Knotweed - Persicaria wallichii

  17. Hottentot-Fig - Carpobrotus edulis

  18. Japanese Knotweed - Fallopia japonica

  19. Large-Flowered Waterweed - Egeria densa

  20. Mile-a-Minute Weed - Persicaria perfoliata

  21. New Zealand Pigmyweed - Crassula helmsii

  22. Parrots Feather - Myriophyllum aquaticum

  23. Red Alga - Grateloupia doryphora

  24. Rhododendron - Rhododendron ponticum

  25. Salmonberry - Rubus spectabilis

  26. Sea-Buckthorn - Hippophae rhamnoides

  27. Spanish Bluebell - Hyacinthoides hispanica

  28. Three-Cornered Leek - Allium triquetrum

  29. Wakame - Undaria pinnatifida

  30. Water Chestnut - Trapa natans

  31. Water Fern - Azolla filiculoides

  32. Water Lettuce - Pistia stratiotes

  33. Water-Primrose - Ludwigia (all species)

  34. Waterweeds - Elodea (all species)

  35. Wireweed - Sargassum muticum

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