A large conspicuous kelp which can grow up to 3.5 m in length in suitable conditions although this length is rarely attained (J. Jones, pers. comm.). The blade is broad, large, tough, flat and divided into 5 - 20 straps or fingers (digitate). The blade is glossy, golden brown to very dark brown in colour. The holdfast is large, conical and branched with conspicuous haptera. The stipe is stiff, rough textured, thick at the base and tapers towards the frond. The stipe stands erect when out of water. The stipe is often covered with numerous epifauna and epiflora. The amount of energy allocated to growth of the stipe, and consequently maximum length of stipe, varies with season, the age of plant and location.

Link for Algaebase

Laminaria hyperborea is a large, leathery kelp in the family Laminariaceae. Because there is a lot of commercial and industrial interest in Laminaria hyperborea, this species has been extensively studied over the years throughout its habitat range. The large and conspicuous holdfast is conical with branched rhizoids, resembling the foot of a bird. The stipe of Laminaria hyperborea is long and circular in cross section, thicker at the base and tapering upwards. The stipe is stiff rather than flexible, and can snap when bent by strong waves if it has been cut or nicked. The stipe's rough texture makes it easier for epiphytic red algae and epiflora to cover its surface, especially in older plants. The color of the smooth and glossy blade can range from yellowish brown to golden brown to very dark brown. The blade of Laminaria hyperborea is large, tough, flat, lacks a midrib, and usually split into from 5 to 20 fingers or straps (digitate). Regarding size, the stipe is usually up to 1 meter long but stipes up to 3 meters long have been recorded. The blade length varies with season, age of plant and location, but is commonly around 1 meter, and reaching over 2 meters in suitable conditions. Thus, the entire thallus (plant) of Laminaria hyperborea can often exceed an impressive 2 meters.

Laminaria hyperborea is a long-lived perennial species and has a life span of 10 to 20 years, in contrast to other Laminaria species in the upper sublittoral, which have a typical life of about 3 years. Longevity is thought to be higher in its northern distribution. Blade area and stipe length of adults grow rapidly until about 5 years old. In 1-year old Laminaria hyperborea plants however, growth mainly occurred in the lamina in order to maximize the area for photosynthesis in the light limited understory. Laminaria hyperborea also follows a distinct seasonal growth pattern. Peak growth occurs during winter (November to June) and stops in summer, although metabolic rate remains high. Each November the new blade starts growing below the old one, leaving a distinct collar between the two; the growth continues until around June. Nutrients from the old blade contribute to the growth of the new blade, and the old blade tissue is shed in the spring and early summer. The amount of energy allocated by Laminaria hyperborea to growth of the stipe, and consequently maximum length of stipe, varies with season, the age of plant and location. If the Laminaria hyperborea is growing in a more exposed location with stronger wave and tidal forces, more growth is allocated to the stipe and hapteron to help secure it to the substratum. Also, in sheltered conditions the blade has few or no digits and the stipe becomes thin, but in exposed conditions the blade is deeply digitate and the stipe becomes thick.

Laminaria hyperborea is often difficult to distinguish from Laminaria digitata, particularly when plants are young. However, the stipe of Laminaria digitata is darker and usually oval in cross section instead of cylindrical, is not thicker at the base, does not snap easily, and does not have epiphytes on the stipe. Also, the belt of Laminaria hyperborea is nearly always below (in deeper water) any belt of Laminaria digitata. Laminaria ochroleuca is a similar species, but has a smooth stipe (not rough like Laminaria hyperborea), and its fronds are typically more golden or yellow. Saccorhiza polyschides, another commercially utilized kelp, appears similar to Laminaria hyperborea from the frond, but has a twisted stipe near a bulbous haptera, which is very different from Laminaria hyperborea's bird claw holdfast.

Laminaria hyperborea can be found on bedrock or other stable substrata in cold temperate waters of the sublittoral zone. It may also grow on stable boulders, pebbles on large gravel, deeper parts of pontoons and moorings and other man-made structures. Laminaria hyperborea does not grow in areas subject to sand scouring but can sometimes be found in areas of siltation. Its depth ranges from the extreme low water mark to depths dependant on light penetration - typically about 8 meters depth in turbid coastal waters to 30 or 40 meters in very clear coastal waters. Laminaria hyperborea grows as dense forests under suitable conditions, and thins out in deeper waters. Laminaria hyperborea grows in weak to moderately strong currents, but is unable to survive where wave action is extreme (such as in coastal surge gullies), since its stiff stipe, topped with a large lamina, is prone to being snapped.

Link for Algae Handbook (Pereira, 2010).

Link for Seaweeds Industry Association

Direct industrial applications - removal of heavy metals

Direct medicinal applications - gynaecology/obstetrics

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

Source of hydrocolloids - source of alginate and laminaran; Contains: alginates/alginic acids; laminarins/laminarans.

Source of organic chemicals excluding hydrocolloids - source of polyols; Contains: mannitol

Terrestrial plant and animal production - animal feed (additive); Contains: ash; carbohydrates; fibre; lipids; protein; water.

Terrestrial plant and animal production - animal feed (direct); Contains: ascorbic acid (vitamin C); calcium; carbohydrates; cobalamin (vitamin B12); iodine; iron; laminarins/laminarans; magnesium; manganese; mannitol; niacin (vitamin B3); protein; riboflavin (vitamin B2); saturated fatty acid; sodium; thiamin (vitamin B1).

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

Other uses: In Europe, Laminaria hyperborea is one of the two kelp species commercially exploited by the hydrocolloid industry, the other being Laminaria digitata. Laminaria hyperborea is also utilised by the cosmetic and agrochemical industries and for biotechnological applications, and by the food industry for emulsifiers and gelling agents. Drift kelp has long been collected as an agricultural fertilizer and soil conditioner, and is Laminaria hyperborea is still harvested and used in popular kelp meal fertilizer products. Laminaria hyperborea is a source of laminarin and mannitol, which are used in industrial and other applications. Because of its ability to absorb and retain water, Laminaria hyperborea has been used in wound dressings to prevent adhesions, and has also been used to help dilate the cervix during childbirth.

Kain (Jones), J.M. (1971). Synopsis of biological data on Laminaria hyperborea. FAO Fisheries Synopsis No 87(Rev. 1): 74.

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

McHugh, D.J. (2003). A guide to the seaweed industry. FAO Fisheries Technical Paper 441: x + 105, 64 figs.

Common names used in commerce, often for edible algae: oarweed {Eng}

Other names: Anguillier, barrai raic, baudrée, bezhin avel, bezhin ebren, ceann a’ tSlat, cuvie, cuvy, feamainn dearg, goémon d’avril, havetare, hestatare, kurvtare, laminaire rugueuse, laminaria rugosa, laminària rugosa, mantelet, mayweed, múrach bealtaine, múrach foghmhair, Palmentang, Palmetang, palmetare, redware, ruwgesteeld vingerwier, scothach, screadhbhuidhe, sea rod, sea rods, sgothach, skrame, Slat mara, stokktare, stolpetare, stortare, Stórthari, tali-ebrel, tali-penn, tangle, troll tare, trolltare

Basionym: Fucus hyperboreus Gunnerus