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Initially focused in Asia, this industry has been increasingly more prevalent in Western Europe, including Ireland. Currently 44% of all aquaculture is algal aquaculture (FAO, 2002). At present, algae is used in the food, cosmetics, pharmaceuticals, fertiliser, filtration, and animal fodder industries, with 90% of all commercial algae sourced via aquaculture (Walsh and Watson, 2011). However, Ireland has a long history of harvesting algae for use in fertiliser (Verling 1990, 40), food and the production of pottery and glass as far back as the 12th Century (Guiry, 2010).

Evidence for gathering and consumption of seaweed is present in historical texts, literature, art-historic sources, and in the Irish oral tradition (see O’Murchu 2002; Verling 1986, 40; Irish Folklore Commission). One of the earliest textual references we have for the harvesting of seaweed in the Irish tradition comes from the poem ‘Buain Duilsigh’ which was written by an anonymous Irish monk in the 12th century.

Buain Duilisg

Seal ag buain duilisg do charraig
seal ag aclaidh
seal ag tabhairt bhidh do bhoctaibh
seal i gcaracair.

A while gathering dillisk from the rock
a while fishing
a while giving food to the poor
a while in a cell.

Once harvested seaweed could be eaten as food or taken in folk tonics and cures. Sleabhac (Porphyra dioica) for example was believed to be an aphrodisiac and a treatment for gout, while dilisk was ingested to eliminate worms and to remedy ‘women’s longing’ (WWW1). Seaweeds such as kelp were also burned in features known as kelp kilns to reduce the organic material to ash containing potash and soda. This material could then be be used in the glazing of pottery, and the production of glass and soap (ibid). Evidence also exists for the harvesting of seaweed for consumption during the famine and as a source of fertiliser when no manure was to be had (Verling 1986, 40).

Currently, with over 500 species of seaweed identified along Ireland’s coastline, the Irish algae industry has a value of €18 million per annum (Morrissey et al., 2011), and is expected to reach €30 million per annum by 2020 according to the Sea Change Strategy (2006). Despite being under similar constraints as fish farming, the industry continues to boom. Annually, Ireland produces over 36,000 tonnes of algae (Walsh and Watson, 2011) through culturing facilities, such as the Roaringwater Bay Sea Vegetable Company.

In 2004, BIM set up a pilot scale hatchery to develop techniques in growing various kelp species as part of a broader bord of works investigating the potential of farming seaweed in Ireland, with a preliminary focus on Atlantic Wakame (Alaria esculenta). This work was based at the Daithi O Murchu Marine Research Station on Sheeps Head Peninsula in West Cork. Advances in the techniques for the hatchery and ongrowing, particularly of kelp and dulce (Palmaria palmata), will lend to a further increase in this industry in Ireland, providing, not only additional income and employment, but also a whole range of new marine based products.

To learn more about the different types of seaweed along Ireland’s coastline see the Irish ‘Macroalgae Factsheet‘, or watch last weeks episode of EcoEye, where Anja Murray investigates the potential pressures the recently awarded licence for mechanised seaweed harvesting in Bantry Bay may have on coastal marine ecosystems and their importance to ocean life.

Seán & Orla-Peach


*Mariculture: Branch of aquaculture involving the cultivation of marine organisms for food and other products in the ocean, tanks, ponds or raceways which are filled with seawater.


FAO (2002) The state of world fisheries and aquaculture, FAO, Sofia.

Indergaard, M. and Minsaas, J. 1991 2. Animal and Human Nutrition. in Guiry, M.D. and Blunden, G. 1991. Seaweed Resources in Europe : Uses and Potential. John Wiley & Sons.

Guiry, M (2010). ‘History of Seaweed in Ireland’. In ‘World Seaweed Resources’, UNESCO. Ed. A.T. Critchley, M. Ohno. D.B. Largo.

O’Murchu, T. (2003) Beara woman talking : the lore of Peig Minahane, folklore from the Beara Peninsula, Co. Cork /Collected by Liam Ó Murchú ; edited, arranged and translated by Martin Verlag. Mercier Press, Cork.

Morrissey, K., O’Donoghue, C., & Hynes, S. (2011). Quantifying the value of multisectoral marine commercial activity in Ireland. Marine Policy, 35(5), 721–727.

Sea Change (2006). A Marine Knowledge, Research and Innovation Strategy for Ireland, 2007-2013. Marine Institute. 172pp.

Walsh, M., & Watson, L. (2011). A market analysis towards the further development of seaweed aquaculture in Ireland. Irish Sea Fisheries Board, Dublin, Part 1, 1– 48

WWW1 – Heritage Council Seaweed Poster 

WWW2 – Irish Folklore Comission: Seaweed – Wexford

WWW3 – Irish folklore Comission : Seaweed – Donegal