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Class:

Phaeophyceae

Genus:

Fucus Linnaeus

Species:

Fucus serratus

Authority:

Linnaeus

Description:

Fucus serratus is a robust, olive-brown shrubby seaweed. It can grow in high densities low on the shore, forming dense mats of long ribbons up to 1 meter long and 2 to 5 centimeters across. It attaches to rocks via a discoid holdfast about 3 centimeters in diameter. Though technically a brown alga, it can vary in color from olive green through reddish brown (though it often has a greenish tint). It typically grows up to 70 centimeters but has been recorded at over 2 meters in length in very sheltered environments. The flat, strap-like fronds have a forward-pointing serrated edge, a distinct midrib, and grow from a short stipe. The fronds are bifurcating (splitting in two repeatedly). Fucus serratus is similar to Fucus vesiculosus, but lacks the air bladders which are very visible on Fucus vesiculosus. Fucus serratus is also similar to Fucus spiralis, but is not spirally twisted. The frond surface of Fucus serratus has numerous pin-pricks with clusters of tiny white hairs. It grows grows profusely in a wide variety of situations from exposed rocky shores to saline lagoons. It is most commonly found on sheltered, hard, rocky substrata on the lower part of somewhat sheltered coastlines, subject to some degree of disturbance such as from tidal scour. Its growth rate varies considerably depending on environmental conditions, but can range from 4 to 12 centimeters per year. Fucus serratus plants may become detached and lost to winter storms.

Original publication: Linnaeus, C. (1753). Species plantarum, exhibentes plantas rite cognitas, ad genera relatas, cum differentiis specificis, nominibus trivialibus, synonymis selectis, locis natalibus, secundum systema sexuale digestas. Vol. 2 pp. [i], 561-1200, [1-30, index], [i, err.]. Holmiae [Stockholm]: Impensis Laurentii Salvii.

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Original description: Download PDF from Algaebase

Name History

Adjective (Latin), serrated, saw-edged with teeth pointing forwards (Stearn 1973)

Biogeography

Fucus serratus is a seaweed of the north Atlantic Ocean. It extends from the Canary Islands and northern Portugal along the Atlantic coast of France, into the British Isles and North Sea coasts, and into the western Baltic. It is found in Scandinavia up to Novaya Zemlya, around Iceland, and over to the Gulf of St. Lawrence in the western north Atlantic, ranging from Chaleur Bay and the tip of Cape Breton to Bar Harbor, Maine.

Life Cycle

Monogenetic lifecycle

Uses and compounds

Health, cosmetics, thalasotherapy, wellness & folk medicine - mineral supplement; Contains: ascorbic acid (vitamin C)

Provide biological, medical and pharmacological activity - antimicrobial

Source of hydrocolloids - source of alginate; Contains: alginates/alginic acids; fucose; laminarins/laminarans

Terrestrial plant and animal production - animal feed (additive)

Terrestrial plant and animal production - fertiliser; Contains: ash; copper; iron; manganese; molybdenum; nitrogen; organic matter; strontium; water; zinc.

Other uses: Fucus serratus survives by filtering the ocean for nutrients and as a result, amasses a huge amount of minerals and vitamins. Used for hundreds of years in seaweed baths, the oils from this seaweed have positive effects on skin, hair and body. The antioxidant compounds found naturally in this seaweed have long been known to have pronounced anti-aging, skin conditioning, repair and hydrating effects. This seaweed is used as a food, and is harvested for cosmetics, and it is harvested to make fertilizer. Its edible properties are very similar to that of bladderwrack and interest in this plant is growing, as, being a thyroid stimulant it might could counter obesity by increasing the metabolic rate. It is also known to help women with abnormal menstrual cycling patterns and/or menstrual-related disease histories. It can be stored dried to make a nutritious tea as well as for use in soups and stews as a flavoring. This species is collected, dried and used as a soil additive as well. Fucus serratus is used by over a dozen businesses across the United States, Australia, France, Italy, Ireland, and the UK in a wide variety of products, such as:

anti-aging and eye serums
facial moisturizers and sunscreens
a dental care compound
revitalizing compound used in skin and hair products
hair shampoos and conditioners
bath soak products
cleansing lotions
body buffs and gels
hand creams
facial washes, cleansers, and toners
fertilizers

Harvesting: Fucus serratus is known to be harvested in the UK, France, and Ireland.

Harvesting Techniques: Fucus serratus is harvested by hand at low tide. One recommendation is to cut at a height of 15 to 25 centimeters above the holdfast.

References

Brawley, S.H., Coyer, J.A., Blakeslee, A.M., Hoarau G., Johnson, L.E., Byers, J.E., Stam, W.T., & Olsen J.L. (2009). Historical invasions of the intertidal zone of Atlantic North America associated with distinctive patterns of trade and emigration. Proceedings of the National Academy of Sciences of the United States of America 106: 8239-8244.

Braune, W. (2008). Meeresalgen. Ein Farbbildführer zu den verbreiteten benthischen Grün- Braun- und Rotalgen der Weltmeere. pp. [1]-596, 266 pls. Ruggell: A.R.G. Gantner Verlag.

Loiseaux-de Goër, S. & Noailles, M.-C. (2008). Algues de Roscoff. pp. [1]-215, col. figs. Roscoff: Editions de la Station Biologique de Roscoff.

Habitat:

On firm substrata in the lower intertidal; often zone-forming.

Common names:

English: Toothed Wrack

Other names: an mhíoránach, black wrack, blackweed, dubhlamán, feamainn dhubh, fucus denté, fucus dentelé, gemeiner Blasentang, gezaagde zee-eik, míoránach, múrach dubh, Sägetang, savtang, saw wrack, serrated wrack, toothed wrack, varech denticulé, zaagwier

Type information:

Type locality: “Oceano” (Silva, Basson & Moe 1996: 902). Type: LINN