Useful Information about Seaweed

What are Seaweeds / Sea Vegetables / Algae?

Seaweeds are marine algae. Macro algae – large algae.
(There are also microalgae – tiny algae that in the sea, make up plankton).
Seaweeds are sea plants – plants that grown in the sea. The nutrients / vitamins / trace elements are more readily available (digested) in seaweeds / sea plants than they are in land plants.
edible-seaweedSeaweeds / Algae are identified by their colous and comprise of 3 phyla / divisions :

  • Brown Algae / Seaweed – Phaeophyta
  • Red Algae / Seaweed – Rhodophyta
  • Green Algae / Seaweed – Chlorophyta

There are about 10 000 species

  • Brown Seaweed / Algae –
  • Phaeophyta – 2 000 species
  • Red Seaweed / Algae –
  • Rhodophyta – 6 000 species
  • Green Seaweed / Algae – Chlorophyta – 2 000 species

The Global Seaweed –
Algae Industry
Of the global seaweed harvest 85% – 95% goes to the food industry and is worth approx €4.1 billion p. a.
The most valuable crop produced by seaweed aquaculture is Nori – Porphyra – a red seaweed / alga. The value of this crop is around US$ 2 billion p.a. (approx 130 t dry weight)
The seaweed that produces the largest amount by aquaculture is Laminaria japonica – similar to the Irish Seaweed Laminaria digitata.
China produces around 3.8 million tonnes p.a. of Laminaria japonica
Most of the seaweed industry is centred around the Far East.
The majority of the seaweed industry is by aquaculture in Japan, China and North & South Korea.
World Production of Seaweed – Algae
World Production of Seaweed (Algo Rhythme, No. 31, CEVA, Pluebian, France)

World Production of Seaweed (Algo Rhythme, No. 31, CEVA, Pluebian, France) 
 Country / Area Algae / Seaweed(fresh weight million t)  World Production (%)
 China 4.093   59
 Korea  0.771  11
 Japan  0.737  10
 Phillipines  0.404  6
 Norway  0.185  2.6
 Chile  0.182  2.6
 USA  0.116  1.6
 France  0.079  1.1
 TOTAL  6.941  100
 Ireland  0.032  0.46

Algae Species harvested and cultivated globally

Species of Seaweeds – Algae – Harvested, Cultivated and Amounts

Metric Tonnes per year dry weight 
 Seaweed – Algae Species – Name  Cultivated  Harvested
 Laminaria – Kelp – Kombu  673 064  58 413
 Porphyra – Nori  130 614  8
 Undaria – Wakame  101 708  20 006
 Chondrus – Irish Moss – Carrageen – Carragheen  1  12 213
 Hizikia  6300  1200
 Monostroma – Green Nori  1250  –
 Irish Seaweed / Algae    10

Irish Seaweeds has embarked on an Aquaculture Project with Queen’s University Belfast
Seaweeds / Algae from Ireland
Since the 18th Century over 500 different species of seaweed / algae have been identified around the shores of Ireland.
With the Gulf Stream and Ireland being located between 51 and 55 °N, many warm water species of seaweed / algae are at their Northern Limit and also some cold water species are at their Southern Limit.
Of the 500 species around the shores of Ireland, only a few are harvested and used commercially.
These areas of economic value are :

  • Food and food supplements – edible seaweeds / algae that are sold as sea vegetables (sea veg, sea veggies)
  • Fertilisers, liquid seaweed extracts and soil conditioners
  • Raw material for seaweed polymers such as the alginate industry
  • Cosmetics, body care, thalassotherapy and medicinal preparations.

The algae species that are harvested commercially are :

Seaweed / Algae Species of Ireland that are harvested 
Seaweed / Algae Species of Ireland that are harvested Latin Name Common Name(s)
Brown Seaweed
Alaria esculenta Dabberlocks, Wing Kelp, Murlins
Fucus serratus Serrated Wrack
Fucus spiralis Spiral Wrack
Fucus vesiculosus Bladderwrack
Himanthalia elongata Thongweed, Buttonweed, Sea Spaghetti
Laminaria digitata Kelp, Kombu, Haidai, Oarweed,Tangleweed, Sea Girdle
Laminaria saccharina Sweet Kelp, Sweet Kombu, Kombu Royale,Sugar Kelp, Sugar Wrack, Sea Belt
Also known as L. saccharina Saccharina latissima As above
Ascophyllum nodosum Knotted Wrack, Asco, Rockweed
Red Seaweed
Palmaria palmata Dulse, Dillisk, Shell Dulse
Porphyra Nori, Sloke, Laver
Chondrus crispus Carrageen, Carragheen, Carrageen Moss,Irish Moss, Jelly Moss
Lithothamnion corallioide Maerl
Green Seaweed
Ulva lactuca Sea Lettuce
Enteromorpha intestinalis Sea Grass, Sea Spirulina
Codium fragile Sponge seaweed, Sponge Weed