Exhibition « Seaweeds from the Côte des Légendes »
Le
SEAWEED: WHAT IS IT ?
Seaweeds, a type of algae, are living organisms that generally develop in aquatic environments. They contain chlorophyll, a green pigment present in both terrestrial and aquatic plants. Chlorophyll captures energy from the sun’s rays, converting it into vital energy for the plant. This is the process of photosynthesis.
Through the combination of water, mineral salts, light and carbonic gas, seaweeds develop their own matter and produce oxygen.
Back to the beginning
Around 3 billion years ago, blue-green bacteria were already using chlorophyll to capture the sun’s light. Some predators created what we refer to as a symbiosis* with these bacteria (instead of digesting them).
* Symbiosis is an association of two organisms to share mutually beneficial properties.
These associations gave rise to the first green and red microscopic algae, around 1.5 billion years ago. Other symbioses developed around 200 million years ago: for example, between red algae and their predators, resulting in the large brown algae we know today – wrack and kelp.
The diversity of algae species (shape, colour and dimensions) is explained by their successive evolutions over billions of years.
Their colour varies according to the pigments they contain. In fact, they have long been classified by their colour.
Morphology of the majority of algae :
There are thousands of species of algae in the world. As the seventhlargest seaweed bed in the world, Brittany boasts the greatest diversity in Europe (700 to 800 macroalgae, or seaweed, species).
Each species of algae develops where the conditions (temperature, substrate type, light levels, water salinity, emersion/immersion) are most favourable.
Oxygenated water, stirred up by the Breton tides, promotes their development.
Seaweed distribution across coastal zones
Seaweeds grow from the landward part of the coast, right down into deeper waters. Several coastal zones can be distinguished on which seaweeds thrive:
- Supralittoral zone (above the sea = sea-spray zone)
Presence of terrestrial plants known as « halophytes » (which grow in salty environments) and the grey, black and yellow lichens* that can be seen on the rocks.
*Lichens also represent a form of symbiosis (association of two living organisms). One of the two is a mushroom, while the second is an alga or bacteria.
- Midlittoral zone (foreshore = intertidal zone)
Area covered with water at high tide and uncovered at low tide. In the highest part, we find wrack (brown algae) which can withstand emersion and, as a result, significant variations in temperature and salinity.
Further down, where spring tides uncover the foreshore, we find some red algae (pioka and dulse) and green algae (sea lettuce).
A little further down the foreshore, sea spaghetti grows.
- Infralittoral zone (under the sea)
There, we find kelp beds (large seaweed with blade-shaped fronds). Kelp appreciate cold waters, high in nutritional salts, and grow at depths of up to 30 metres.
GREEN ALGAE
Sea lettuce (Ulva lactuca)
Ranging from green to pale green in colour, and with a slightly crinkled texture, this seaweed appreciates nutrient-rich waters.
It should be cut just above its small hook (its stipe) and rinsed in sea water before being taken home, as it tends to hold onto grains of sand.
Enjoyed fresh on the foreshore: metallic, woody, artichoke and sorrel flavours. When it comes to this delicacy, opinions vary according to each individual’s palate.
At home: dry while protecting from sunlight (as this will destroy its pigment), stretched out on plastic crates or on a terry towel if you want to crumble it into flakes. Keep whole to wrap ‘en papillote’ dishes. This seaweed will retain its flavour, texture and colour when frozen.
Sea lettuce is high in magnesium, iron, calcium, potassium and vitamins A, C, B3 and B12. Its protein content varies between 20–30% of its dry weight.
It has anti-inflammatory and antioxidant properties. It helps regulate cholesterol levels and prevents cardiovascular risks.
Recipe for seaweed crisps
by Hubert Grall (Brigoudou association)
Ingredients:
Fresh or rehydrated sea lettuce
1 egg white
Cornflour
Frying oil and fleur de sel
Brush egg white on each side of the seaweed.
Sprinkle with cornflower and shake to remove excess.
Immerse in oil for a few seconds, then drain on absorbent paper.
Salt and serve immediately.
Aonori (Ulva intestinalis) – Gutweed
Often known as « sea hair », it is also compared to intestines due to the similarity of its morphology.
Though it seems to easily detach from the rock, it must be cut with scissors to be collected. Choose the greenest seaweed and leave them in seawater for a while on the foreshore before eating.
It has a salty, fairly neutral and delicate taste on the palate.
To dry it, we recommend gently shaking then draining and placing it on a cloth out of the sunlight. It will quickly dry in a car parked in the shade, for example. This seaweed very quickly flakes between the fingers. Store it in a jar as you would with parsley or thyme, etc.
With almost as much magnesium as sea lettuce, it contains even more iron: 3 tablespoons of flakes will provide your daily dose of iron. Likewise, it is high in calcium, potassium and protein. It also contains sulphated polysaccharides that help protect cell walls and strengthen immunity. It has the same anti-inflammatory and antioxidant molecules as sea lettuce.
Recipe for creamy seaweed sauce
by Régine Quéva
This sauce pairs wonderfully with hot potatoes.
Ingredients:
Lemon juice
1 shallot
1 pinch Cayenne pepper
20 cl crème fraîche
1 teaspoon gutweed
In a bowl, mix salt, pepper and lemon juice.
Add finely chopped shallot and crème fraîche, followed by seaweed flakes.
Taste and adjust seasoning with Cayenne pepper.
RED ALGAE
Dulse (Palmaria palmata)
This seaweed has flat, double-webbed blades with smooth and regular edges. On the rocks, it can be recognised in bushy red (or even purplish) bunches. It yellows in the sunlight. Dulse can reach up to 70 cm. It is located quite low down in the intertidal zone and can be collected at tidal coefficients of above 70.
It has a slightly sweet taste, reminiscent of periwinkle or abalone.
To store it: dry fresh seaweed near a source of heat, placed on a crate or tray. As soon as it begins to crumble, place it in an airtight container in a shaded location, whole or in flakes. It freezes very well: place it in a freezer bag with all air removed.
The protein content of dulse varies according to the seasons and harvest: between 25% and 30% of its dry weight. It also offers potassium, vitamins A, B6, B12 and C, iron, magnesium and calcium.
This red algae remineralises, detoxifies and drains. It is a vermifuge with multiple properties: antioxidant, anti-inflammatory, anti-viral, anti-microbial and anti-diabetic.
Dulse in sweet and savoury dishes:
- Mix raw dulse with grated carrots and courgettes, or add it to a fruit salad. It brings a salty and slightly sweet touch to a starter or dessert.
- As a garnish, it enhances rice, soups and pasta, etc.
Recipe for onion and dulse soup
by Hubert Grall (Brigoudou association)
Ingredients (serves 6):
6 pink Roscoff onions
3 tablespoons flaked dulse
3 tablespoons flour
40 g butter
1 teaspoon sugar
1 tablespoon sherry vinegar
1 glass white wine
1 litre stock (ideally kombu stock)
Salt, pepper
Croutons, rouille and 40 grams grated cheese
Mince onions in a casserole dish and lightly brown in butter. Add sugar and mix.
Deglaze with vinegar, add dulse, then sprinkle with flour and mix.
Add the stock and wine and bring to the boil, then salt, pepper and leave to simmer for 30 minutes.
Pour into bowls and bake au gratin in the oven for a few minutes.
Serve with croutons, rouille and grated cheese.
NORI (Porphyra Sp.)
This is a dark, shiny seaweed, stretched out like a black film, which sometimes seems to envelop rocks. It exists in several varieties in different shades of purple.
It should be cut by leaving a few centimetres on the stalk, and picked sparingly from various rocks so that it grows back everywhere.
Rinse with seawater before eating raw during picking from the rocks, as it can retain sand within its folds.
Though its taste may seem unremarkable at first, a slightly smoky flavour emerges on the finish.
This seaweed is not easy to dry. Ideally, it should be stretched out fresh on plastic crates and crumpled up when dry. A good tip is to finish off drying in front of a fireplace or open oven. (The white flakes that may appear on its surface are magnesium salts – good for your health).
Nori is a record-breaker in terms of protein: up to 47% of its dry weight.
It provides vitamin B12 (required by vegetarians) and is high in potassium, calcium, magnesium and phosphorous.
Recipe for savoury shortbread
by Annie (Brigoudou association)
Ingredients:
200 g flour
100 g parmesan
180 g butter
3 tablespoons flaked nori
2 egg yolks
Pepper
Mix all ingredients with your fingers.
Shape into a roll, then cover in cling film and place in the freezer for 15 minutes.
Preheat the oven to 170°C.
Cut the roll into one-centimetre-thick slices.
Place the rounds on a tray and bake for around 20 minutes.
CHONDRUS CRISPUS – Pioka – Irish moss
This reddish seaweed appears like a curly tuft reaching a maximum of 10 centimetres, with a rubbery texture.
It can be found towards the bottom of the foreshore and at mid-tide.
Thanks to its rather elastic texture and neutral taste, it is of little interest to eat fresh on the foreshore. It is collected for its gelling and thickening molecules.
It has various food uses and was once used as a cough mixture. Today, it acts as a gelling agent in many foods (like flans). Its extracts appear under the name E407 or carrageenan in everyday products.
To dry it, stretch it out for several days in the sun on a cloth, for example. It is important that it loses its iodine content. Once dried, store in a glass jar (it will not be affected by sunlight).
The gelling properties of Chondrus crispus are even more effective when paired with a substance containing proteins or calcium, such as animal milk.
Recipe for pioka flan
by Esther Goualt
Ingredients:
1 litre cow’s or plant-based milk
10 g dried pioka
60 g whole cane sugar
Flavouring of your choice: vanilla, cardamom, saffron, cinnamon or chocolate.
Cover the pioka with fresh water to rehydrate.
Drain once it has regained a soft and gelatinous consistency.
Mix with milk and add sugar.
Bring to the boil, then allow to cook on a very low heat for a few minutes.
Add your chosen flavouring and pour the mixture into ramekins.
The flans will set as they cool.
BROWN ALGAE
Wracks
These are mainly collected for their cosmetic and medicinal benefits (high in calcium and selenium).
Fucus serratus (toothed wrack)
Fucus serratus is common on the foreshore of the Pays Pagan. It can be recognised by its notched edges, and often grows under bladder wrack (another wrack with floating air bladders).
The ends are collected when young and tender, using scissors. Its taste is similar to baby cornichons.
These wracks provide fibre, calcium, magnesium, potassium, sodium and vitamin B8, useful for the skin and hair, etc.
Recipe for marine salad
by Régine Quéva
Ingredients:
2 potatoes
2 tomatoes
20 g fresh Fucus serratus
100 g tuna
Shallot, vinegar, oil
Cook the potatoes and cut into rounds.
Chop the shallots, cut the wrack into small pieces, cut the tomatoes and crumble the tuna.
Season and mix.
Sea spaghetti (Himanthalia elongata)
This seaweed can be found in the form of long, thin strips that gradually divide into two and develop from a small brown disk attached to the rock.
It is precious and easy to collect, cook and store. It can be found at the very bottom of the foreshore, accessible during spring tides. It is ideally collected in May–June, as it becomes too thick after this period.
Its blades grow annually, though the entire plant takes two years to grow.
On the palate, it has a crunch and reveals a salty and smoky flavour.
Once cut, it will not last long in the air or water, and so must be quickly prepared. Ideally, the youngest blades should be stored in the freezer and the oldest in jars, in a half water/half cider vinegar mixture brought to the boil, or in slightly salted, boiled water. This way, it will keep for a long time, with a melt-in-the-mouth texture.
Sea spaghetti is high in fibre, potassium, iodine and magnesium, among other benefits.
Consumed fresh, it provides vitamin C, vitamin E and plenty of vitamin A.
Recipe for tagliatelle with smoked salmon and sea spaghetti
by Hubert Grall (Brigoudou association)
Ingredients (serves 4):
300 g tagliatelle
200 g sea spaghetti
2 eggs
20 cl crème fraîche
150 g smoked salmon
1 mandarin
Juice of half a mandarin
Cook tagliatelle for 10 minutes and sea spaghetti for 25 minutes.
While cooking, finely dice the salmon, peel the mandarin and cut into quarters.
Squeeze the juice of the second mandarin and set aside.
Drain the tagliatelle and sea spaghetti, sprinkle with mandarin juice, then add salmon and crème fraîche.
Before serving, add beaten eggs, salt, pepper and continue cooking for two minutes over a low heat to bring together.
Royal kombu (Saccharina latissima) – Sugar kelp – Devil’s apron
This large seaweed, crimped on the sides, is a kelp located at the very bottom of the foreshore. It is therefore collected during spring tides, cutting just above the stipe.
Remember to check current regulations to find the minimum size authorised for harvest.
Please note that no kelps may be eaten raw, as they contain high quantities of iodine.
Once cooked, dry on a washing line – a warm day will take care of it. Fold or flake, or even roll up in a jar filled with a mix of water and cider vinegar, brought to the boil. To store fresh, we recommend rolling up in a freezer bag then removing the air.
Royal kombu is high in fibre and provides iodine, magnesium, calcium, potassium, phosphorous, iron, zinc and several vitamins (A, C, D, E and K), as well as around 20% protein.
It has antioxidant, anti-inflammatory, and anti-coagulant properties. It detoxifies, remineralises and regulates arterial pressure.
In cooking, kombu is great for making fish en papillote.
Recipe for seaweed tartare
by Esther Goualt
Ingredients:
A large bowl of dried seaweed (sea lettuce, nori, dulse, kombu, sea spaghetti, etc.), mixed and flaked.
3 shallots
1 garlic clove
2 tablespoons cider vinegar
1 tablespoon honey
Juice of two lemons
1 cup olive oil
1 tablespoon of an aromatic herb of your choice (Esther recommends lemon balm)
In a salad bowl, mix seaweed with the chopped shallots, grated garlic and aromatic herbs.
Dissolve the honey in the vinegar and add to the seaweed mixture, with lemon juice and oil.
Fill a sterilised jar with the tartare and leave at room temperature for 2 to 3 days (the seaweed and shallots will soften in the mixture).
This tartare can be kept for around 1 month in the fridge (as long as the seaweed remains covered in oil).
Harvesting seaweed today
Harvesting kelp by boat
With its cold waters, stirred up by the tides, Finistère is home to a real wealth of seaweed and enjoys some of the largest kelp beds in Europe. These large brown algae, Laminaria digitata and Laminaria hyperborea, are harvested by seaweed farmers in boats equipped with a Scoubidou or a Norwegian comb.
70,000 tonnes of kelp are collected each year and delivered to two alginate-production factories in France: Algaia (Lannilis, Finistère) and JRS Marine Products (La Forest-Landerneau, Finistère).
In order to preserve algal resources, this harvesting is subject to specific monitoring by the Breton Regional Fisheries Committee and Ifremer (the French Institute for Sea Research and Exploitation).
It is permitted from April to October, encouraging seaweed gatherers to diversify their activities with shellfishing in the Roadstead of Brest in winter (replacing their Scoubidou with a dredger), for example.
Gathering seaweed from the foreshore
Shore-seaweed gathering, in other words, collecting seaweed by hand from the foreshore at low tide, between sunrise and sunset (depending on when the lighthouses are switched on).
Some thirty shore seaweed species are collected in Brittany and sold fresh, dried or ground by processing companies. The main species collected today are Himanthalia (sea spaghetti) for food and cosmetics and Ascophyllum nodosum (knotted wrack).
Pharmaceutical industries use alginates to create gastric dressings and dental impressions. In cosmetics, seaweed extracts are used as rejuvenating active ingredients for the skin.
For many years, this practice was a seasonal activity open to casual gatherers, just like that of pioka (Chondrus crispus) in summer, for example. Today, it is mainly centred around professionals equipped with a regional licence (176 licences granted in 2020).
Strict regulations govern harvesting periods, authorised species and harvesting techniques. Professionals must declare their harvest on a monthly basis, allowing departmental maritime agencies to carry out dedicated monitoring of resources and adapt regulatory measures if necessary.
A few figures
9th largest seaweed-producer country in the world
2nd largest producer country in Europe, after Norway
1,600 harvesting jobs (shore and on-board harvesting)
80 processing and marketing companies
35 seaweed-gathering boats operating in Brittany (Lanildut, Plouguerneau, Landéda and Roscoff)
Leisure seaweed gathering
Good practices for eco-citizens
- Consult the regulations for the region in question
Though no macroalgae are toxic, their gathering is subject to regulations which change each year.
Visit the Finistère Prefecture website to download the « La récolte de loisir des algues de rive sur le littoral du département du Finistère » document [Leisure shore-seaweed gathering on the coast of Finistère] (document also available from the reception desks of the Maison de Territoire).
Find more information at foodalgues.bzh
- Suitable tools
A wicker basket to rinse the seaweed with sea water (or a bucket if you don’t have one), a pair of scissors and boots.
- Basic techniques
Only gather living seaweed attached to rocks
Cut to promote regrowth (do not pull)
Leave rocks in place
Do not gather young seaweed (refer to regulatory sizes and quantities)
Gleaning = harvesting by leaving bunches intact
Gather according to your needs, without excess
- Tides
A few precautions:
Choose a day with a coefficient of at least 90, leave 1.5 hours before the tide and make your way down with the water.
Check the sanitary quality of the water (town hall or dedicated website).
Seaweed on your plate
Long collected for their gelling properties, seaweed can also be consumed like vegetables or herbs. Here are a few tips to add them to your daily cooking:
All collected seaweed should be rinsed in fresh water (at least 3 baths).
Preparing seaweed:
- Fresh seaweed
Blanch in salted boiling water, then cook for 20 to 30 minutes depending on thickness.
- Dried seaweed
For seaweed flakes (dulse, nori and green algae): these can be rehydrated directly in fats or fromage blanc, etc.
For sea spaghetti and kombu: rehydrate these seaweeds for five minutes in warm water.
- Frozen seaweed
For sea spaghetti, for example: blanch in salted boiling water for 3 minutes, drain and store in freezer bags.
MORE INFO: Find local recipes based on seaweed in a dedicated booklet at the reception desks of the Maison de Territoire!
What next?
Cultivating the sea?
In France, the majority of seaweed is gathered, while in the rest of the world, 97% of seaweed comes from seaweed farming or algaculture (particularly in Asia).
Demand for seaweed has boomed in human and animal food industries, cosmetics, agriculture and even biomaterials. French production is therefore no longer sufficient.
Seaweeds represent a very useful resource for three reasons:
- fast reproduction
- growth without food or fresh water
- oxygen production
Their cultivation can contribute to:
- fighting climate change
- protecting biodiversity
France Haliotis (Plouguerneau), Algolesko or C-Weed Aquaculture (Saint-Malo) are three companies operating offshore concessions for seaweed cultivation (sea lettuce, kombu and dulse). Seaweed is sown in-house, then taken out to sea before being harvested by hand.
Seaweed cultivation could be the way forward, allowing us to meet growing demand while creating new jobs. However, it’s important to remember that this will involve developing specific know-how. It will also be necessary to find available cultivation areas at sea, bearing in mind possible conflicts of use with other coastal users (fishers, oyster farmers, pleasure boaters, etc.).
A base of bio-sourced materials?
Several laboratories, mainly based in Brittany (Ifremer and Lebam in Brest or the C.N.R.S. biological station in Roscoff), are gradually discovering the surprising properties of seaweed.
Crop-protection products have been developed thanks to collaborative research between the C.N.R.S. and the Goémar company (Saint-Malo). Liquid extracts made from brown algae are sprayed onto plants. Molecules present in these seaweeds act on seed germination, bacteria resistance and crop yield.
In the Côtes d’Armor, the CEVA Algae Experimentation and Development Centre collaborates with industrial partners to implement alternative, eco-friendly materials
> Algopack in Saint-Malo offers compostable plastics containing 50 to 100% brown algae.
> Algo in Rennes produces eco-friendly seaweed-based paint.
Today, seed film coatings made from seaweed can replace petrochemical-based films.
In Hamburg, algae installed on the outer walls of a block of flats provides hot water and heating.
Certain industries are already using seaweed-based ingredients for their raw materials (leather work).
Tanguy Mélinand is a creator based on Landéda, making clothes from kelp. The procedure, which he developed in 2021, allows him to retain the natural texture of kelp, outside of its natural environment. This seaweed fashion designer collects Laminaria digitata and Saccharina latissima from the coast of Saint-Marguerite in Landéda to develop an alternative leather. His goal is not to create a large-scale business, but to enrich research into seaweed as a viable and biodegradable material.
Though new uses of seaweed are being developed in several sectors, the question of this resource’s availability currently prevents large-scale use.
To find out more
- Maison de l’Algue Seaweed Centre
In the port of Lanildut, dive into the Iroise Marine Park to learn everything there is to know about local seaweed and, in particular, kelp.
- Seaweed-Gatherer Eco-Museum
In the centre of Plouguerneau, discover how the seaweed-gathering profession has developed over the years.
- Maison des Abers in Saint-Pabu
Located on the edge of the Aber Benoît and along the GR34 long-distance hiking trial, this information centre is dedicated to the natural and culture heritage of the Abers, offering activities focused on seaweed, for example.
To spot them during spring tides
Seaweed outings with the Brigoudou association in Plounéour-Brignogan-Plages
Seaweed outings with Esther Goualt in Kerlouan
‘Estran’ordinaire’ foreshore discovery with Nadia Chichiarelli in Plounéour-Brignogan-Plages
To try them
Restaurants, according to weekly menus: La Butte in Plouider, Surnaturel in Kerlouan, Le Moulin du Couffon in Kerlouan and L’Hôtel de la Mer in Plounéour-Brignogan-Plages.
Discover a range of seaweed-based products in the Maison de Territoire shop.
France Haliotis in Plouguerneau offers a range of seaweed (sea lettuce, royal kombu) in condiments.
To see them from a new perspective
Anne Dayot’s photography
« La biodiversité littorale, vue par Mathurin Méheut » [Coastal Biodiversity, As Seen by Mathurin Méheut], Michel Glémarec