Pelvetia canaliculata, often called channelled wrack, is a very common brown alga (Phaeophyceae) of Europe. It is the only species remaining in the monotypic genus Pelvetia. It is relatively small, not growing longer than 15 centimeters. When viewed underwater, its color can be light olive green, and sometimes yellowish brown. Pelvetia canaliculata's color can range from dark brown to dark olive to very dark or blackish green when dried. Its extremities can appear swollen and with orange during spring and summer. These bumpy, irregularly v-shaped swellings with forked tips at the ends of the fronds are its reproductive structures. It appears bushy and grows in dense tufts. Each frond is curled longitudinally (rolled lengthwise) to form a distinct channel. It is irregularly dichotomously branched; each tough and thick branch is of uniform width up to 1 centimeter, lacks a midrib, and lacks air vesicles or bladders. Pelvetia canaliculata is a perennial species; it is at least two years old before it reaches maturity, and has a life span of up to 4 or 5 years, growing 3 to 4 centimeters per year.

Pelvetia canaliculata grows attached to hard substrata with a small basal disc on the upper shore, and forms the uppermost zone of algae growing at or above high water mark. It needs periods of exposure to the air, and sometimes grows so high up a beach that coarse grass and other longshore angiosperms grow among it. Pelvetia canaliculata is found right at the top of the beach in sheltered to moderately exposed areas where it can dry out completely to become black and crispy. When it is dessicated, it has the appearance of being stunted and dead, but it is not the case.

One of the most significant attributes of Pelvetia canaliculata is its ability to withstand dessication and a wide range of exposure conditions. It can survive several days without being covered by the tide and often only gets splashed by the sea’s spray. In fact it requires these relatively dry conditions - if channelled wrack is submerged for more than 6 hours out of 12 it begins to decay. Its physiology is perfectly adapted to these difficult conditions (variations in temperature, light, current, freshwater rain, and salinity). To cope with the light, desiccation, heat, the rythm of the tides, Pelvetia canaliculata has developed sought chemical and biological countermeasures. The deeply channelled fronds help it to retain moisture when the tide is out, which is partly why it can grow so high up on the shore; these channels and a mucus layer help prevent the seaweed drying when the tide is out. Pelvetia canaliculata is very tolerant of desiccation, surviving up to 8 days out of the water. It may spend up to 90 percent of the time out of the water and can tolerate 65 percent water loss. During the rising tide, it rehydrates rapidly upon contact with the water. The species can photosynthesize when exposed to air but may suffer nutrient stress as it can only obtain nutrients when submerged.

Link for (Pereira, 2010) Handbook Guide

Link for Seaweed Industry Association

Original publication: Decaisne, J. & Thuret, G. (1845). Recherches sur les anthéridies et les spores de quelques Fucus. Annales des Sciences Naturelles, Botanique, Troisième série 3: 5-15, pls 1, 2: 40 figs.

 Download PDF from Algaebase

Provide biological, medical and pharmacological activity - anticoalgulant; Contains: arabinose; fucoidins/fucoidans; fucose; galactose; glucose; peptides.

Source of hydrocolloids - source of alginate and fucoidan. Contains: fucose.

Terrestrial plant and animal production - animal feed (direct).

Other uses: Pelvetia canaliculata was historically harvested for use as animal fodder, and in certain areas there are still animals which graze on the growing plants. It has also been collected historically as a source of food for people. It is included in dozens of products from Italy, France, UK, and the United States. According to one leading cosmetics producer, Pelvetia canaliculata stimulates the synthesis of collagens and proteoglycans, which are responsible for giving connective tissue its elastic properties. Using it as a compound can increase the skin’s firmness and reduce the appearance of lines and wrinkles. It is reported from another leading cosmetics company that it increases microcirculation and can help reduce fat and cellulite. Pelvetia canaliculata can be found on ingredient labels for moisturizing lotions, masks and creams, and in body creams, day creams, and night creams. It is found in quality restorative and hydrating serums, and in compounds and extracts used in different products. For food, it is sold in different dried forms, and as a seasoning mix.

Cho, G.Y, Rousseau, F., Reviers, B. de & Boo, S.M. (2006). Phylogenetic relationships within the Fucales (Phaeophyceae) assessed by the photosystem I coding psaA sequences. Phycologia 45: 512-519.

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

In English: Channeled Wrack

Other names: algue à gouttière, caisíneach, caisineach no muirin na muc, channel-wrack, channelled wrack, dúlamán, groefwier, múirín na muc, pelvecia, pelvétia, pelvétie, pelvétie cannelée, Rinnentang, Rinnentaug, zakjeswier.

Type species: This is the type species (holotype) of the genus Pelvetia.

Basionym: Fucus canaliculatus Linnaeus