BIOTIC Species Information for Fucus vesiculosus
Researched byNicola White Data supplied byMarLIN
Refereed byDr Stefan Kraan
Scientific nameFucus vesiculosus Common nameBladder wrack
MCS CodeZR384 Recent SynonymsNone

PhylumChromophycota Subphylum
Superclass ClassPhaeophyceae
Subclass OrderFucales
Suborder FamilyFucaceae
GenusFucus Speciesvesiculosus

Additional InformationNo text entered
Taxonomy References Howson & Picton, 1997, Wippelhauser, 1996,
General Biology
Growth formFoliose
Feeding methodPhotoautotroph
Mobility/MovementPermanent attachment
Environmental positionEpifloral
Typical food typesNot relevant HabitAttached
BioturbatorNot relevant FlexibilityHigh (>45 degrees)
FragilityIntermediate SizeLarge(>50cm)
HeightUp to 1.5. m in the U.K. Growth Rate0.48 cm / week
Adult dispersal potentialNone DependencyIndependent
General Biology Additional InformationAir bladders or vesicles are produced annually to make the frond float upwards when immersed, except at highly exposed coasts where no air bladders are produced (S. Kraan, pers. comm.). Fucus vesiculosus supports few colonial organisms, but provides substratum and shelter for the tube worm Spirorbis spirorbis, herbivorous isopods, such as Idotea, and surface grazing snails, such as Littorina obtusata.

Growth Rate
The growth rate of fucoids is known to vary both geographically and seasonally (Lehvo et al., 2001). Relative growth rate can vary from 0.05-0.14 cm/day depending on temperature and light conditions (S. Kraan, pers. comm.). The increase in growth rate for Fucus vesiculosus at 10, 12.5 and 15 °C was found to be, on average, 280% higher than it was at 7 °C (Strömgren, 1977). In the northern Baltic, the highest relative growth rate of vegetative branches for Fucus vesiculosus was observed in the summer (up to 0.7% / day ) compared to winter growth (less than 0.3% / day). In Sweden, growth rates of 0.7-0.8 cm / week were reported over the summer months of June and August (Carlson, 1991).

Growth rate can also vary with exposure. In Scotland, Fucus vesiculosus at Sgeir Bhuidhe, a very exposed site, grew about 0.31 cm / week whereas plants at Ascophyllum Rock grew an average of 0.68 cm / week (Knight & Parke, 1950). The proportion of energy allocated between vegetative and reproductive growth also varies throughout the year. In the northern Baltic, reproductive branches experienced a peak in growth rate in mid April where the relative growth rate was almost 0.1% / day (Lehvo et al., 2001).
Biology References Knight & Parke, 1950, Lehvo ., 2001, Carlson, 1991, Strömgren, 1977,
Distribution and Habitat
Distribution in Britain & IrelandAll coasts of Britain and Ireland.
Global distributionSee additional information.
Biogeographic rangeNot researched Depth rangeNot relevant
MigratoryNon-migratory / Resident   
Distribution Additional InformationThe morphology of the plant varies in response to the environmental conditions leading to distinct varieties. Also, the fact that it can hybridize freely with other fucoids leads to the formation of distinct varieties (S. Kraan, pers. comm.). This species can survive in exposed locations, even though it is not a preferred habitat, but survive as a dwarf form (S. Kraan, pers. comm.). Plants from exposed locations usually have no airbladders and are known as Fucus vesiculosus forma linearis. The loss of airbladders is thought to be because they increase a plants drag, making them more vulnerable to being washed off by waves. Depth is not relevant as the plant is intertidal although it does occur at shallow depths in the Baltic.

Global distribution
Fucus vesiculosus is found in the Baltic Sea, Faroes, Norway (including Spitsbergen), Sweden, Britain, Ireland, the Atlantic coast of France, Spain and Morocco, Madeira, the Azores, Portugal, the North Sea coast of Denmark, Germany, the Netherlands and Belgium and the eastern shores of United States and Canada.

Substratum preferencesBedrock
Large to very large boulders
Small boulders
Gravel / shingle
Artificial (e.g. metal/wood/concrete)
Physiographic preferencesOpen coast
Strait / sound
Ria / Voe
Enclosed coast / Embayment
Biological zoneUpper Eulittoral
Mid Eulittoral
Wave exposureModerately Exposed
Very Sheltered
Tidal stream strength/Water flowStrong (3-6 kn)
Moderately Strong (1-3 kn)
Weak (<1 kn)
Very Weak (negligible)
SalinityReduced (18-30 psu)
Full (30-40 psu)
Variable (18-40 psu)
Habitat Preferences Additional Information
Distribution References Hardy & Guiry, 2003, Guiry & Nic Dhonncha, 2002,
Reproduction/Life History
Reproductive typeGonochoristic
Developmental mechanismInsufficient information
Reproductive SeasonDecember until late summer Reproductive LocationWater column
Reproductive frequencyAnnual episodic Regeneration potential No
Life span3-5 years Age at reproductive maturityInsufficient information
Generation time1-2 years FecundityPossibly >1,000,000 eggs
Egg/propagule sizeInsufficient information Fertilization typeExternal
Larval/Juvenile dispersal potentialInsufficient information Larval settlement periodInsufficient information
Duration of larval stageInsufficient information   
Reproduction Preferences Additional InformationThe species is highly fecund often bearing more than 1000 receptacles on each plant, which may produce in excess of one million eggs. Development of the receptacles takes three months from initiation until gametes are released. On British Shores, receptacles are initiated around December and may be present on the plant till late summer. In Sweden receptacles were reportedly present from February through to October (Carlson, 1991).
In England, the species has a protracted reproduction period of about six months which varies only slightly in timing between a population at Wembury on the south coast of Devon and one at Port Erin, Isle of Man (Knight & Parke, 1950). Gametes may be produced from mid winter until late summer with a peak of fertility in May and June. According to Berger et al. (2001), Fucus vesiculosus reproduced in either of two periods in the Baltic, the first period being early summer (May - June) and the second being late autumn (September - November).
Plants are dioecious. Gametes are generally released into the seawater under calm conditions (Mann, 1972; Serrão et al., 2000) and the eggs are fertilized externally to produce a zygote. In the Baltic, summer spawning plants produced smaller but more eggs than plants reproducing in late autumn (September - November): egg production was approximately 210,000 eggs / gram frond mass with an egg size of 0.067 mm and 89,000 egg / gram frond mass with an egg size of 0.07 mm for summer and autumn periods respectively (Berger et al, 2001). Both periods experienced a similar recruitment success. Eggs are fertilized shortly after being released from the receptacle. On the coast of Maine, sampling on three separate occasions during the reproductive season revealed 100% fertilization on both exposed and sheltered shores (Serrão et al., 2000). Fertilization is not considered as a limiting factor in reproduction in this species (Mann, 1972; Serrã0 et al., 2000). Zygotes start to develop whenever they settle, even if the substratum is entirely unsuitable. The egg adheres to the rock within hours of settlement and the germling may be visible to the naked eye within a couple of weeks (Knight & Parke, 1950). The zygote is sticky (S. Kraan, pers. comm.) and may adhere firmly enough to resist removal by the next returning tide (Knight & Parke, 1950). Mortality is extremely high in the early stages of germination up to a time when plants are 3 cm in length and this is due mostly to mollusc predation (Knight & Parke 1950). In the Baltic, for example, a total of more than 1000 fertilized eggs per cm² were observed on the sea floor around the females over the two month reproductive season (Serrão et al., 2000). By the end of the season, however, the number of germlings growing in the same area was at least an order of magnitude lower.
The timing of reproduction in this species can, to a certain extent, be influenced by wave exposure and reproduction is sometimes initiated earlier in sheltered condition (Knight & Parke, 1950). In Finland, the amount of energy proportioned to reproduction was significantly higher on exposed sites than sheltered localities (Bäck et al, 1991).
Reproduction References Knight & Parke, 1950, Munda, 1997, Bäck et al., 1991, Serrão et al., 2000, Berger et al., 2001,
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