BIOTIC

BIOTIC Species Information for Fucus vesiculosus

Researched by

Nicola White

Data supplied by

MarLIN

Refereed by

Dr Stefan Kraan

Taxonomy

Scientific name

Fucus vesiculosus

Common name

Bladder wrack

MCS Code

ZR384

Recent Synonyms

None

Phylum

Chromophycota

Subphylum

Superclass

Class

Phaeophyceae

Subclass

Order

Fucales

Suborder

Family

Fucaceae

Genus

Fucus

Species

vesiculosus

Subspecies

Additional Information

No text entered

Taxonomy References

Howson & Picton, 1997, Wippelhauser, 1996,

General Biology

Growth form

Foliose
Shrub

Feeding method

Photoautotroph

Mobility/Movement

Permanent attachment

Environmental position

Epifloral

Typical food types

Not relevant

Habit

Attached

Bioturbator

Not relevant

Flexibility

High (>45 degrees)

Fragility

Intermediate

Size

Large(>50cm)

Height

Up to 1.5. m in the U.K.

Growth Rate

0.48 cm / week

Adult dispersal potential

None

Dependency

Independent

Sociability

Solitary

Toxic/Poisonous?

General Biology Additional Information

Air 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 & Ireland

All coasts of Britain and Ireland.

Global distribution

See additional information.

Biogeographic range

Not researched

Depth range

Not relevant

Migratory

Non-migratory / Resident

Distribution Additional Information

The 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 preferences

Bedrock
Large to very large boulders
Small boulders
Cobbles
Pebbles
Gravel / shingle
Artificial (e.g. metal/wood/concrete)

Physiographic preferences

Open coast
Strait / sound
Sealoch
Ria / Voe
Estuary
Enclosed coast / Embayment

Biological zone

Upper Eulittoral
Mid Eulittoral

Wave exposure

Moderately Exposed
Sheltered
Very Sheltered

Tidal stream strength/Water flow

Strong (3-6 kn)
Moderately Strong (1-3 kn)
Weak (<1 kn)
Very Weak (negligible)

Salinity

Reduced (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 type

Gonochoristic

Developmental mechanism

Insufficient information

Reproductive Season

December until late summer

Reproductive Location

Water column

Reproductive frequency

Annual episodic

Regeneration potential

Life span

3-5 years

Age at reproductive maturity

Insufficient information

Generation time

1-2 years

Fecundity

Possibly >1,000,000 eggs

Egg/propagule size

Insufficient information

Fertilization type

External

Larvae/Juveniles
Larval/Juvenile dispersal potential	Insufficient information	Larval settlement period	Insufficient information
Duration of larval stage	Insufficient information

Reproduction Preferences Additional Information

The 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,