In Ireland only two species are harvested in any large quantities, i.e., Ascophyllum nodosum and the calciferous algae known under the collective name of maerl. A third species, Laminaria is harvested in small quantities, but there is potential for larger extractions. A number of smaller brown, red and green algae are harvested and marketed for human food and cosmetics. The Irish seaweed industry, concentrated along the west coast from Co. Donegal to Co. Waterford, consists of over 25 companies, employs over 700 people and generates about €15 million annually. The main products coming out of the industry include: foods and food supplements, fertilizers, soil conditioners, body-care and cosmetics, seaweed baths and medicinal preparations. Ireland has a small seaweed industry compared to other countries such as France were the seaweed industry employs several thousand people and was worth €l 54 million in 1998 (National Seaweed Forum Report 2000). Seaweed production in Ireland is around 35,000 tonnes compared to the annual global production of 8 million tonnes of wet seaweed with an estimated value of USS 6 billion (McHugh 2003). Nevertheless, it is a source of employment in peripheral coastal areas where alternative employment is scarce. The preservation of coastal maritime communities is critical for the development of a national sense of cultural identity and the seaweed industry, in tandem with aquaculture and has played an important role in the maintenance of such communities.
The seaweed resources in Ireland are primarily made up of wracks (Ascophyllum nodosum, F ucus spiralis, F. vesiculosus and F serratus), kelps (mainly L. digitata and L. hyperborea) and coralline algae collectively known as maerl. With aid of funding from the Marine Research Measure (Operational Programme for Fisheries, 1994-1999) via Ireland’s national Marine Institute, an Ascophyllum nodosum algal biomass survey was carried out at the west coast of Ireland by the Irish Seaweed Centre (ISC) in 1997 in conjunction with the seaweed company Arramara Teo. The distribution of Ascophyllum nodosum resource on a county by county basis along the west coast, from Donegal to Cork was surveyed with the assistance of the seaweed buyers from the company to asses the amount of seaweed that could be harvested from a particular stretch of shore (Hession et al .1998). The findings ofthe biomass survey identified a potential yield of 75,000 tonnes of Ascobhyllum per aimum in a sustainable manner, almost four times the amount harvested in 2003 (Table 1 and Fig. 1).
With the aid of funding from the European Community under the ‘Energy, Environment and Sustainable Development’ Programme a short-term kelp harvesting, monitoring and surveying programme was carried out by the Irish Seaweed Centre. Using biomass figures per m2, the minimum biomass was calculated for Galway Bay of 3.4 kg/m2 for L. digitata in summer and the maximum of 19.05 kg/m2 for L. hyperborean in winter. An average biomass for kelp over all seasons was estimated at 7.63 kg/m2. The standing stock in Galway Bay was calculated at 763,000 tonnes of kelp. Harvesting of 10% of the standing stock is seen as sustainable practise if harvested in different sectors along a stretch of coastline (Vea Unpubl.).