Are you looking for a seaweed industry professional? Do you want to understand the different seaweed production methods? To have an idea of the volumes available? On this page, you’ll find an interactive map listing the stakeholders working with seaweed (non-exhaustive list). A description of the macro-algae and micro-algae production methods as well as their volumes is also provided.
Enjoy reading!
Find industry stakeholders On the map below, you can find the seaweed industry stakeholders for each business line, by seaweed type (macro-algae or micro-algae) or by keyword. You can also zoom in on the map to find the stakeholders near you.
You can also find different information on the websites below:
Are you looking to purchase seaweed? You can contact the resource stakeholders above or go to the Place des algues which brings together seaweed sellers and buyers.
Seaweed production in France
On a global scale, seaweed production (36 million tonnes in 2019 according to FAO data) is mainly obtained through farming (99%). France, the second largest European producer after Norway has the completely opposite situation with 99% of its production from harvesting wild resources.
Macro-algae
Macro-algae is sourced in different ways: harvesting by boats, on foot or algaculture (between sea and land) or gathering washed up or drifting algae for certain applications.
Boat and foot harvests are subject to strict regulations (decrees, decisions by regional prefectures, etc.). They are also subject to fishing or harvesting licences.
These are issued by the Comité Régional des Pêches Maritimes et des Elevages Marins (CRPMEM – Regional Sea Fishing and Marine Farming Committee) in Brittany for example or by the government departments (Regional Prefecture, DIRM [Interregional Directorate for the Sea]) in other regions where regulations are gradually being put in place. These licences, which are limited in number, and annual decrees enable sustainable management of the resource by limiting the harvesting volumes, areas, periods and methods. It is also compulsory to declare harvests and inform the CRPMEMs (area, species, volume, etc.)
Seaweed bottom fishing with boats equipped with Norwegian harvesting heads on the right (Photo credit: CDPMEM 29)
In Brittany, 77 shore seaweed harvesting licences and 35 fishing licences are issued by the CRPMEM. In Pays de Loire, up to 20 shore seaweed harvesting licences can be issued by the Regional Prefect. Other regions or departments have not yet established a quota but have implemented a similar licensing or administrative authorisation system (Normandy, Charente Maritime).
Boat harvesting concerns the laminaria used to produce alginate (Laminaria digitata and Laminaria hyperborea ). It represents a volume varying between 50,000 and 70,000 tonnes depending on the year.
Harvesting on foot is done by professionals mainly at strong tides. The species mainly harvested are Ascophyllum nodosum, Fucus sp., Chondrus crispus/Mastocarpus, Himanthalia elongata, Palmaria palmata, Saccharina latissima, Ulva sp. and Porphyra sp. The annual tonnage varies between 4,000 and 4,500 tonnes.
Seaweed farming, although practised in the sea or pools on land, currently accounts for less than 1% of the volume produced in France. It mainly concerns Undaria pinnatifida and Saccharina latissima. Land farming enables the production of biomass under environmental conditions that are more controlled than at sea, which enables more precise quality control, standardisation, traceability, safety and seaweed composition. It is not, however, suitable for all species, in particular laminaria. Sea farming represents a higher biomass potential, but it is more exposed to environmental conditions.
Seaweed bottom fishing by boats equipped with a scoubidou
Finally, seaweed may have washed ashore, when it was ripped up by a storm (this is the case with Gelidium sp. in the Basque country, or Solieria sp in the south of Brittany and Vendée) or when there is a greed tide phenomenon (Ulva) which is mainly found in Brittany and to a lesser extent in Normandy and the Pays de la Loire. Seaweed washed ashore is not allowed in human food (the seaweed must be harvested from its roots and not all species are allowed) and is therefore often used for spreading and composting, except for Gelidium sp which is used to produce bacteriological agar. Its methanisation has also been studied. A few supply chains to higher added-value markets (fertiliser, bio-stimulants, extracts for animal feed) are also being put in place.
Micro-algae and cyanobacteria
Micro-algae farm in open pools (Credit: Cyanotech Corporation; In the study ‘Transforming the Future of Marine Aquaculture: A Circular Economy Approach’ by the authors Charles H. Greene, Celina M. Scott-Buechler, Arjun L.P. Hausner, Zackary I. Johnson, Xin Gen Lei and Mark E.)
French micro-algae production is negligible in terms of volume in relation to that of macro algae. The main species grown in France is spirulina (Arthrospira sp.) and its production has increased in recent years. In 2021, the production was 63 tonnes. Other species (Chlorella sp., Tetraselmis sp., etc.) are also grown in lesser proportions (4 tonnes in 2021).
Micro-algae can be produced in open pools, in photobioreactors or fermenters.
Farming in open pools requires little investment with a high biomass production potential for reduced operational and energy costs. The size varies by a few m² to several thousand m² according to the production target and/or the surface available. The pool may or may not be covered with a greenhouse according to the geographical location.
Photobioreactor farming enables better control of the farming environment and the quality of the biomass. Various systems exist, the most common of which is built from vertical or horizontal glass tubes with a small diameter. This farming method nevertheless requires high investments and operational costs as well as high energy consumption.
Photobioreactor micro-algae farming (Credit: IGV Biotech under the licence CC BY-SA 3.0. ‘Photobioreactor PBR 4000 G IGV Biotech’)
The production of micro-algae by fermentation has emerged recently as a production method enabling us to reach higher volumes than the two other production methods, but it is not applicable to all species. On heterotrophic layers (which may develop without photosynthesis), the production capacities are much greater when the upscaling is successful. This farming technique nevertheless requires high investment and maintenance costs but overcomes the problems of location and climate, and to a lesser extent the surface area available, with the process enabling production to be concentrated in a much smaller surface area.
