Practical ecological knowledge for the temperate reader.

Fucus - Rockweed

"Bladderwrack seaweed (Fucus vesiculosus) is a species of brown algae that grows on the northern coasts of the Atlantic and Pacific oceans and the North and Baltic seas." [FAP Rogers] "Although it is widespread along the coastlines in virtually every part of the world and is possibly one of the more valuable of all the species of seaweeds, it is held in relatively low esteem." [Mouritsen Seaweeds]

"The male and female reproductive organs may occur on the same or separate organisms, and some species produce eggs and sperm all year long. Fucus is a perennial alga with a lifespan of up to four years." [FAP Rogers]

Local Species;

  1. Fucus distichus - no common name [E-flora]
  2. Fucus spiralis - no common name [E-flora]

Species Mentioned;


"The iodine content in kelp may cause hyp"er- or hypothyroidism. In view of this, ingestion of kelp preparations by children is inadvisable. The iodine content in kelp has also been associated with acneiform eruptions and aggravation of pre-existing acne." [HerbalMed3]

"In general, brown seaweeds are known to concentrate various heavy metals and other toxic elements." [HerbalMed3]

Edible Uses

"Sometimes used for collecting herring eggs. Used by Tanaina as salty seasoning. Boiled and eaten by eskimos of Greenland. Can be used acceptably, past its prime in late summer. Can be laid on campfire coals as a bed for barbecuing fish.Rinsed briefly in cool to lukewarm (never hot) water. Use immediately or store in the fridge. For long-term storage, dry spring-harvested Fucus rapidly in the sun. When brittle, store in a cool, dry place. I've found that drying bladderwrack slowly with artificial heat produces a poor tasting product.The sun-dried or fresh sea vegetable, steeped as tea, yields a broth reminiscent of chicken bouillon. It' s excellent as a hot beverage and as the basis for a consommé or stew." [???]

"A common food in Japan, it is used as an additive and flavoring in various food products in Europe. It is dried and made into a nutritious tea, added to soups, particularly Japanese- and Chinese-style noodle soups. It flavors stews, fortifying them with iodine. I like to put a dried piece in my mouth and suck on it until soft, and then chew and swallow." [Meuninck EWPUH] " It has a strong taste of iodine and is generally very salty, both indicators that bladder wrack has a chemical composition that mirrors that of konbu. It is good in cooked dishes, soups, or sprinkled on salads" [Mouritsen Seaweeds]

F. gardneri; "People pick this algae them from rocks in the spring, after herring lay their eggs on them. The herring and seaweed are eaten together. Cecilia Andrews of Chevak said this species can be braided, hung and stored for winter in seal pokes or in a dry place. They can be soaked and eaten as desired. People on Nunivak Island sometimes eat the seaweed raw without fish eggs on it." [Jernigan EYK]

Soil Additive: "Macroalgae meal is dried, milled macroalgae, and again it is usually based on the brown macroalgae because they are the most readily available in large quantities. Species of Ascophyllum, Ecklonia, and Fucus are the common ones. They are sold as soil additives and function as both fertilizer and soil conditioner. They have a suitable content of nitrogen and potassium, but are much lower in phosphorus than traditional animal manures and the typical N : P : K ratios in chemical fertilizers. The large amounts of insoluble carbohydrates in brown macroalgae act as soil conditioners (improve aeration and soil structure, especially in clay soils) and have good moisture retention properties. Their effectiveness as fertilizers is also sometimes attributed to the trace elements they contain, but the actual contribution they make is very small compared with normal plant requirements." [Barsanti Algae]

Animal Feed: "Pigs are said to thrive on a meal prepared from species of Laminaria, although its digestibility is lower for them than for sheep. Another meal prepared from Fucus vesiculosus, f serratus and Ascophyllum is said to be lower in digestibility than the Laminaria meal. All these meals have some value because of their strong laxative effect. Two different methods of preparing meal are currently used in Norway, one involving natural drying and the other drum drying, the latter producing a product of quite constant quality" [Chapman SU]

Other Uses

Medicinal Uses

"Unproven Uses: Preparations of Bladderwrack are used internally for diseases of the thyroid, obesity, overweight, arteriosclerosis and digestive disorders and externally for sprains." [PDR] "Nowadays, it is no longer used because of the untoward effects on thyroid activity when treatment ceases." [Capasso PQR]

"(Fucus vesiculosis). Helps prevent radiation from being absorbed by the body. Antioxidant and nutritive." [Mars NFA] "Bladderwrack contains alginic acid that swells upon contact with water. When taken orally, it forms a seal at the top of the stomach and is sold over the counter as a heartburn treatment and bulking laxative. Natural health enthusiasts also use the plant to treat dysmenorrhea." [Meuninck EWPUH]

Herbalists recommend Fucus tea as a-tonic for the lungs and as a thyroid-stimulating weight loss aid. I like to sip a cup of the accompanying Fucus blend fifteen minutes before meals. [???]

In A Modern Herbal, Grieve says that a liniment made by bottling the mucilage from Fucus bladders in rum is used ". . . for strengthening the limbs of rickety children. Fucus liniment is also said to be soothing for rheumatic pain. According to Grieve, Fucus wine "... has been praised as a remedy in diseases of the hip and other joints and bones in children." Traditionally, the mucilaginous substance in Fucus bladders is rubbed on skin tumors and corns and rinsed off with salt water. [???]

The California School of Herbal Studies recommends covering sore feet and ankles with warm Fucus and a towel. I like adding this seaweed to footbaths. [????]

"Alginates (sodium and potassium salts) and some specialty carageenans are now being marketed for their effects in combating obesity. The effects are attributed to their prebiotic fibres, and the benefits seen with higher fibre diets. There is a product on the market that is specifically targeting weight loss. It contains Fucus vesiculosus and is sold under the trade name Quantrim™. This product makes a direct claim for weight loss based upon its chelated iodine content, as well as its induction of satiety due to the alginates’ hygroscopic properties (gut bulking)" [Sahoo TAW]

Fucus vesiculosus; "The jelly-like mucilage contained in the swollen vesicles (or pneumatocysts) of Fucus vesiculosus is an age-old embrocation in coastal areas for rheumatism, bruised limbs and sprains. In Britain it has been recorded from Cornwall,60 Somerset,61 Essex,62 Cumbria63 and Angus.64 It was boiled into an oily lotion and rubbed in or simply placed hot against the skin or, more simply still, put in a bath of hot sea-water. The relaxing effect has been valued in Yorkshire fishing villages especially as a cure for bow legs in small children; the fresh fronds and sliced vesicles together with equal parts of water and gin or rum were placed in a corked bottle for a week and then applied as a rub.65 Another unusual use for the plant was encountered by Martin Martin in 1695 in Jura in the Inner Hebrides: steam from the boiled plant was inhaled to cure a stitch after a fever.66... A less orthodox practice recorded from Donegal has been to suck the mucilage out of the vesicles and swallow it to cure a sore throat.70 In official medicine the mucilage was also applied to throats—but externally, as a poultice for glandular swellings." [MPFT]


Fucus vesiculosus; Herb - Thyroid stimulant, weight reducing and demulcent. [BMWH] "Fucus possesses antihypothyroid, antiobesic, and antirheumatic properties." [PDBHM]

"Fucus ceranoides crude extract exhibited protumoral activity by increasing the cell viability of Daudi tumoral cell lines. The phenolic compounds of this extract likely involved in its radical-scavenging activity could also be implicated in this protumoral activity. The ability of phenols to protect cells from oxidative stress has been demonstrated, but these compounds have a contradictory behaviour characterised by anti- and protumoral activities according to their chemical structure, the system and conditions used in the study" [HMA]

"Activities (Fucus) — Alterative (f; MAD); Antiaggregant (1; CAN); Antihypothyroid (f; CAN; PHR); Antiobesity (1; CAN; PNC); Antirheumatic (f; CAN); Antiseptic (1; PNC; PH2); Demulcent (1; PED); Depurative (f; PED); Emollient (1; PED); Hemagglutinant (1; PH2); Hypoglycemic (1; PH2); Immunomodulator (1; PNC); Laxative (1; CAN); Metal-Chelator (PED); Tonic (f; MAD)." [HMH Duke]

"Polysaccharides and polyphenols obtained from Fucus vesiculosus have anti-HIV activity. It has been postulated that adhesion is the fi rst step in HIV infection; the active compounds from Fucus vesiculosus block adhesion which prevents transmission of HIV-1 (Beress et al., 1993). A novel reverse transcriptase inhibitor has been isolated from Fucus vesiculosus. It inhibits HIV reverse transcriptase by competing with the nucleic acid substrate." [HPEP]

"... dietary bladderwrack may prolong the length of the menstrual cycle and exert antiestrogenic effects in premenopausal women." [Hudson WENM]

"Fucus is stated to possess antihypothyroid, anti-obesity and antirheumatic properties. Traditionally, it has been used for lymphadenoid goitre, myxoedema, obesity, arthritis and rheumatism." [HerbalMed3]


The total carotenoid content of Fucus serratus was found to be approximately 0.08% of the dried extracted cells, and fucoxanthin comprises about 70% of the total carotenoid" [Dominguez FIAFN]

Fucoidan (Fucoidin): Fucus spiralis; 9-11% "It has been found that littoral rockweeds contain a higher quantity than do sublittoral plants." [Chapman SU] "Fucoidan extracted from Fucus vesiculosus is commercially available and is composed of 44.1% fucose, 26.3% sulfate, and 31.1% ash, and a little aminoglucose." [Marine Algae] "Fucoidan is a sulfated polysaccharide of Fucus vesiculosus, which has a wide spectrum of biological activities. It contains L-fucose as the main sugar constituent, which can interact with transforming growth factor-β (TGF-β) that can scavenge oxygen species. Fucoidan can partially prevent carbon tetrachloride (CCl4)-induced liver fibrosis in a preclinical model." [Sahoo TAW]

"Accumulation [of heavy metals] has been shown to be controlled by salinity of the medium with bladder wrack (brown alga, Fucus vesiculosus L.) (9)." [Barker HPN] " The sea weed Fucus vesiculosus has the capability of desorbing and accumulating Cu adsorbed onto particles of suspended sediment (Luoma and Bryan 1982)." [Bini PHE]

"It has been found that Fucus vesiculosus gives mostly labelled 18:1 fatty acids at 5°C" [BMNP]

Fucus Sp. (Greenland) 13 mg per 100g fresh wt. Ascorbic acid [Chapman SU]

"Fucus vesiculosus is the dominant habitat-providing seaweed along rocky shores in the Baltic Sea, and phlorotannins act as effective defenses in the adult seaweed against most grazers (Jormalainen and Honkanen 2008)." [ECOStud - 219]

Protein content (%, dry matter basis) ( a: Total nitrogen (% dry weight); b: % crude protein; c: % pure protein.)

Dried Fucus spp (Per ct.); 88.7 total dry matter, 5.2 Protein, 4.2 Fat, 9.4 Fiber, 53.6 N-free extract, 16.3 Total minerals, 0.83 Nitrogen [GGMM Stamets]

F. vesiculosis; 1-43 mg/g K (Potassium) and 11-17 mg/g Ca (Calcium), 0.5-55mg/g Na (Sodium), 0.13-10mg/g mg (Magnesium), and 3 mg/g P (Phosphorus) (All figures in mg/g d.w.) [HMA]

"Lanosol enol ether 357, originally isolated from the brown alga Fucus vesiculosus has been shown to be an antibacterial and antifungal component of the brown alga Osmundaria serrata (Barreto and Meyer, 2006)" [HMA]

Total dry weight content of Fucus is 50%. Insoluble dietary fiber is 40% [Marine Algae]

Slim Sipping: A Tea for Reducing

Blend ingredients and store in airtight container in dark closet. Steep 1 heaping teaspoon herb in I cup boiled water for 5 to 10 minutes. NOTE: Except for bladderwrack, all of the above herbs should be dried in shade. [???]

Cultivation & Propagation

"Within a few years of unfavorable abiotic conditions, the reproductive capacity was dramatically reduced in southern European marginal populations of the intertidal brown alga Fucus serratus" [ECOStud - 219]

"higher pH (10.1), lower inorganic carbon (DIC = 0.6 mM), and possibly a supersaturated O2 condition generated by Ulva intestinalis in temperate rockpools inhibit the growth of Fucus vesiculosus and Chondrus crispus; these species normally coexist in the eulittoral where the prevailing natural open water chemistry lies at pH 8.2 and 2.2 mM DIC" [ECOStud - 219]

"The oogonia and antheridia are produced in groups (sori) on the surface of the thallus. Each oogonium produces a single egg which, like that of Fucus, drifts passively in the water when released." [GPOD]

"First field experiments on photoinhibition in macroalgae were done by Huppertz et al. (1990). They showed that the midday depression of photosynthesis was clearly caused by photoprotection. Specimens of the brown alga Fucus serratus living in intertidal rock pools and, hence, are covered by water during low tide, showed a considerable decrease of photosynthetic activity under excessive natural light conditions. The photoinhibitory state is conserved by moderate desiccation in air in this species because the thalli show the same state of photoinhibition after reabsorbing water as measured before they became uncovered during falling tide. Thereafter it was demonstrated that the photosynthetic oxygen production measured at nonsaturating fluence rates and the optimal quantum yield (Fv/Fm) show an approximately inverse course in comparison with the fluence rate of daylight during the day" [Hanelt SB]

Predation Response: "... in some (but not all) populations Fucus vesiculosus induces defenses (measured as palatability) when attacked by either snails or isopods (Rohde et al. 2004).... In F. vesiculosus, waterborne cues resulting in induction of defenses in neighboring individuals are produced in response to predation by isopods but not snails (Rohde et al. 2004). However, although predation by isopods also directly induces defense production in two other species of Fucus, in these other species there is no induction from waterborne cues" [Hanelt SB] "Along the northwestern coast of the United States, levels of phlorotannins in different population of Fucus districhus differ by about 20%. When these plants were damaged to simulate attack by snails, damaged plants increased phlorotannins by about 20%, resulting in a 50% decrease in susceptibility to snail grazing relative to undamaged control plants (Van Alstyne, 1988)." [Rosenthal HerbV2]

Effect of Disturbance: "Observations of Fucus serratus in the western Atlantic Ocean indicate the likely importance of disturbance in the invasion process, since it occurs most abundantly on friable sandstone substratum (Chapman et al. 2002) and in areas with frequent ice scour (A.R.O. Chapman personal communication). An experimental study examining the invasion of F. serratus on eastern Atlantic shores of Spain has further demonstrated the importance of disturbance in the invasion process (Arrontes 2002). While disturbance to native canopies is not required for establishment of F. serratus, disturbance affects the rate at which establishment occurs, and can significantly accelerate the establishment process. For this species, disturbance increases the probability of successful establishment." [Johnson, SI]

Fungal Assocations "Over a 3-year period, Haythorn et al. (1980) recorded six fungal species from Fucus serratus casts: Dendryphiella salina, Alternaria marina, Asteromyces cruciatus, Sigmoidea marina, and unidentified species of Penicillium and Doratomyces. This low diversity was reflected in collections they made from other seaweed casts with only 19 species (52 isolates) observed growing from 10 different species of seaweeds. The diversity of fungi associated with casts of F. serratus during our from the Dothideales formed the prevailing group, with representatives such as Dendryphiella salina and species of Phoma, Cladosporium, and Alternaria. Other orders observed included the Hypocreales, with isolates from the genera Acremonium, Fusarium, and Trichoderma; the Halosphaeriales; and the Lulworthiales. Isolates from the last two orders were identified as Corollospora angusta, Corollospora intermedia, and Lindra obtusa. The number of isolates recovered from healthy fronds totaled 250 representing 10 orders, with members of the Hypocreales, Halosphaeriales, and Dothideales predominating" [Dighton TFC]

Hybridization: "... many algal genera have extreme levels of phenotypic plasticity and species can potentially hybridize with close relatives (e.g., introduced and native populations of Fucus evanescens and F. serratus" [ECOStud - 219]

Bioremediation: Fucus vesiculosus used as biomass for the removal of Cd, Ni, and Pb from aqueous solution. Fucus spiralis used as a biomass for the removal of Cd from aqueous solution. [Fulekar BT]

"For As, Mn, Co, Ni and Ba the biomagnifications in Fucus were significantly higher than in mussels, whereas Hg and Se were more accumulated in mussels than in algae. No significant concentration differences were observed for P, S, Na, K, Mg, Cu, Cd, Pb, and Zn. Both bioindicators represent different pathways of element uptake (Ostapezuk et al., 1997)." [HMA]

"Fucus vesiculosus (Phaeophyta) is one of the species most often used to perform studies about trace element pollution, specifically to monitor heavy metal pollution (Truus et al., 2004) and radionuclides" [HMA] "(Davis et al. 2002, Nielsen et al. 2005) suggested that Fucus serratus often dominate the vegetation of heavy metal-contaminated habitats." [Phytorem2]


  1. bamfieldmsc -, Accessed Jan 23, 2019
  2. [E-flora] 2017. E-Flora BC: Electronic Atlas of the Plants of British Columbia []. Lab for Advanced Spatial Analysis, Department of Geography, University of British Columbia, Vancouver.