Seaweed and sustainability

For centuries, seaweed has been harvested by Irish coastal communities for use as food, as animal feed and as a soil enhancer.

In Ireland, seaweed is mostly wild-harvested. Harvesting is manual, by hand or by the boat and rake method. Of the seaweed harvested, 98% is Ascophyllum nodosum (Asco), a brown wrack type seaweed predominantly harvested off the west and northwest coast. This seaweed is used to produce high value biostimulants for the agricultural industry with the byproducts from this process sold as low-value animal feed or fertilizer.

Plant biostimulants are inputs to stimulate a crop’s natural nutrition processes, aimed solely at improving the crop’s nutrient use efficiency, tolerance to abiotic stress (negative factors caused by a crop’s environment), quality traits or increasing the availability of nutrients in the soil.

Approximately fifteen other types of brown, green and red seaweeds are harvested around Ireland and are used for the production of higher value products for human and animal health. According to a 2022 Socio-Economic Study of Seaweed Harvesting in Ireland, these seaweeds constitute 2% of the volume of seaweed annually harvested but command higher prices per tonne and so generate 23% of harvester revenue.

Seaweeds provides ecosystem services in coastal areas. They are a food source for many species such as crustaceans, fish and seabirds, and seaweed beds are an essential habitat for many organisms to live and reproduce. Seaweeds provide coastal protection and can also perform bioremediation functions.

Bioremediation using seaweed can clean up excessive nutrients from agriculture or pollutants from industrial activities but the environmental impacts of this must be assessed. It must also be remembered that seaweeds used in remediation may not be suitable for harvesting. It is imperative that marine habitats and seaweed resources are managed in a way that minimises impact to the coastal ecosystem.

The Irish Seaweed Industry

The seaweed industry, from harvesting to processing, contributes over €90 million annually to the Irish economy and employs about 700 people. Seaweed processing businesses range from small artisanal businesses to large multinationals. Seaweed is a key feedstock for the Irish bioeconomy and there is increasing demand for seaweed raw material for the production of plant biostimulants, cosmeceuticals and emerging biochemical and pharmaceutical applications.

The sector is attempting to capitalise on the growing uses for seaweed and its by-products emerging across a number of industries but the challenge is to diversify this industry and grow it in a sustainable manner. More harvested seaweed and cultivated seaweed are needed to meet industry demand, but this need must be met with due regard for the resource, protecting security of supply for the future while also ensuring the rights of those who can harvest seaweed are respected.

In addition to licensed wild seaweed harvesting, there also exists the rights of individuals to harvest wild seaweed related to a property folio or rights built up through harvesting from the same area over a period of time. Ireland’s National Marine Planning Framework commits to supporting the sustainable harvesting of seaweed, having regard to the important economic and social contribution it makes to coastal communities.

It is agreed that there is a need for enhanced policy development in this area that would offer strong economic supports. Regulation is required but must protect resources, ensure security of supply, be equitable and ensure that those with existing harvesting rights can continue protecting tradition.

A Socio-Economic Study of Seaweed Harvesting in Ireland was conducted in 2022 to inform the development of national policy for the sector. It addresses potential of the industry in Ireland, barriers to expansion and sustainability in the industry.