MarLIN

information on the biology of species and the ecology of habitats found around the coasts and seas of the British Isles

Horned wrack (Fucus ceranoides)

Distribution data supplied by the Ocean Biogeographic Information System (OBIS). To interrogate UK data visit the NBN Atlas.

Summary

Description

A large brown intertidal seaweed, restricted to growing in estuaries or near freshwater streams on the shore. Fucus ceranoides does not have airbladders, but the side of the fronds are often inflated.

Recorded distribution in Britain and Ireland

All coasts of Britain and Ireland

Global distribution

Spitsbergen, Iceland, Norway, Heligoland, Netherlands, Ireland, Britain, N. France, Portugal and Azores.

Habitat

Fucus ceranoides is widely distributed in north-west Europe but is only common in brackish water. It is characteristic of estuaries and is often abundant where freshwater streams run onto the shore. The species is found on the middle part of the shore, where it attaches to stones, rocks or gravel.

Depth range

Not relevant

Identifying features

  • Frond thin with smooth margin.
  • Frond fan shaped with prominent midrib.
  • Without air bladders but frond on either side may be inflated.
  • Reproductive bodies narrow, pointed fronds at ends of branches.

Additional information

No text entered

Listed by

- none -

Further information sources

Search on:

Biology review

Taxonomy

PhylumOchrophyta
ClassPhaeophyceae
OrderFucales
FamilyFucaceae
GenusFucus
AuthorityLinnaeus, 1753
Recent Synonyms

Biology

Typical abundanceHigh density
Male size rangeUp to 60cm
Male size at maturity
Female size rangeLarge(>50cm)
Female size at maturity
Growth formFoliose
Growth rateData deficient
Body flexibility
MobilityNot relevant
Characteristic feeding methodAutotroph
Diet/food source
Typically feeds onNot relevant
SociabilityNo information
Environmental positionEpifloral
DependencyIndependent.
SupportsNo information
Is the species harmful?Data deficient

Biology information

Fucus ceranoides is physiologically adapted to brackish conditions. Suryono & Hardy (1997) found that growth rate was highest between 5 and 25 psu and growth was depressed at 0 and 35 psu. When cultured in high salinity they found that plant tissue decayed within 5 to 6 weeks. Khjafi & Norton (1979) recorded similar results but Baeck et al. (1992) found that Fucus ceranoides grew at full salinity for 11 weeks.

Habitat preferences

Physiographic preferencesOpen coast, Strait / sound, Sea loch / Sea lough, Ria / Voe, Estuary
Biological zone preferencesMid eulittoral, Upper eulittoral
Substratum / habitat preferencesBedrock, Cobbles, Gravel / shingle, Large to very large boulders, Pebbles, Small boulders
Tidal strength preferencesModerately Strong 1 to 3 knots (0.5-1.5 m/sec.), Strong 3 to 6 knots (1.5-3 m/sec.), Very Weak (negligible), Weak < 1 knot (<0.5 m/sec.)
Wave exposure preferencesSheltered, Very sheltered
Salinity preferencesLow (<18 psu), Reduced (18-30 psu)
Depth rangeNot relevant
Other preferencesNo text entered
Migration PatternNon-migratory / resident

Habitat Information

The species is commonly found in the upper reaches of estuaries. It appears to be physiologically adapted to living in reduced salinity and exhibits its maximum growth rate at 11 psu. It is thought to be absent from fully saline sites due to an inability to compete with the faster growing fucoids, such as Fucus vesiculosus and a physiological intolerance of fully saline conditions. In areas of estuaries where salinity varies between 11 and 25 psu, Fucus ceranoides and Fucus vesiculosus can be found living together.

Life history

Adult characteristics

Reproductive typeGonochoristic (dioecious)
Reproductive frequency Annual episodic
Fecundity (number of eggs)No information
Generation timeInsufficient information
Age at maturityInsufficient information
SeasonMay - August
Life span2-5 years

Larval characteristics

Larval/propagule type-
Larval/juvenile development Not relevant
Duration of larval stageNo information
Larval dispersal potential No information
Larval settlement periodNot relevant

Life history information

The species is usually dioecious but monoecious plants have been recorded, although it has been suggested that these are hybrids. Well developed gametangia are present on plants in southern Norway from the end of May to December. Gametes are released on daytime high tides at about full and new moon. Germlings are found from the end of May to the beginning of August. Receptacles usually drop off by October or November.

Sensitivity reviewHow is sensitivity assessed?

Physical pressures

 IntoleranceRecoverabilitySensitivityEvidence/Confidence
High Moderate Moderate Low
Fucus ceranoides is permanently attached to the substratum, so would be removed upon substratum loss. In general, fucoids recruit rapidly to cleared areas, but populations of this species are restricted to brackish waters so new individuals may have to recruit in from some distance.
High Moderate Moderate Moderate
If smothering occurred when the tide was out, the whole plant would be buried underneath the sediment, preventing photosynthesis and killing the plant. If smothering occurred when the plant was immersed, some of the frond may protrude above the sediment and not be affected. In general, fucoids recruit rapidly to cleared areas, but populations of this species are restricted to brackish waters so new individuals may have to recruit in from some distance.
Tolerant Not relevant Not sensitive Moderate
Fucus ceranoides is a resident of estuaries, where high levels of siltation naturally occur, so is likely to be tolerant of this factor.
No information
High Moderate Moderate Low
An increase in the level desiccation may result in the upper limit of the species distribution on the shore becoming depressed. A decrease in the level of desiccation may allow the species to grow further up the shore. In general, fucoids recruit rapidly to cleared areas, but populations of this species are restricted to brackish waters so new individuals may have to recruit in from some distance.
High Moderate Moderate Low
Fucus ceranoides would suffer desiccation and nutrient stress on increased exposure to air. An increase in the period of emersion would cause the upper limit of the population to be depressed. Reduced exposure to air would enable Fucus ceranoides to extend further up the shore.
No information
Intermediate Moderate Moderate Moderate
An increase in water flow rate may tear plants of the substratum or mobilise the substratum with the plants attached. The plants with substratum may be washed away to conditions unsuitable for the growth of the species. In general, fucoids recruit rapidly to cleared areas, but populations of this species are restricted to brackish waters so new individuals may have to recruit in from some distance.
No information
Low Moderate Low Moderate
Decreases in temperature are unlikely to have any effect as the species extends to Northern Norway where temperatures are much cooler. Fucus vesiculosus, a similar species, can withstand temperatures of up to 30 degrees C, so the species is also likely to be tolerant of increases in temperature.
No information
Low Immediate Not sensitive Moderate
The growth rate of Fucus ceranoides may be lowered due to a reduction in the light available for photosynthesis. On return to previous turbidity levels, the growth rate would quickly return to normal.
No information
Intermediate Moderate Moderate Low
An increase in wave exposure could cause the plants to be torn off the substratum or mobilise the substratum with the plants attached. The plants with substratum may be washed away to conditions unsuitable for the growth of the species. Increased exposure would also batter the fronds against the substratum subjecting them to abrasion. In general, fucoids recruit rapidly to cleared areas, but populations of this species are restricted to brackish waters so new individuals may have to recruit in from quite far away.
No information
Not relevant Not relevant Not relevant Not relevant
Seaweeds have no known mechanism for noise perception
Not relevant Not relevant Not relevant Not relevant
Seaweeds have no known mechanism for visual perception
Intermediate Moderate Moderate Low
Abrasion may damage and remove fronds and germlings. Abrasion may result from human trampling which can significantly reduce the cover of fucoid algae on a shore (Holt et al., 1997). In general, fucoids recruit rapidly to cleared areas but populations of this species are restricted to brackish waters. Where populations are restricted to the affected area, new individuals may have to recruit in from some distance.
High Moderate Moderate Moderate
Fucus ceranoides is permanently attached to the substratum so once removed a plant cannot re-establish itself. In general, fucoids recruit rapidly to cleared areas, but populations of this species are restricted to brackish waters so new individuals may have to recruit in from some distance.

Chemical pressures

 IntoleranceRecoverabilitySensitivityEvidence/Confidence
No information Not relevant No information Not relevant
Insufficient
information
Heavy metal contamination
Low Very high Very Low Low
Fucus ceranoides accumulates heavy metals in its tissues (Barreiro et al., 1993). However, little is known of how heavy metals affect the species although fucoids are generally quite robust to chemical pollution and do not appear to be harmed by heavy metals (Holt et al., 1997). Intolerance is therefore, reported to be low. Recovery will be rapid as growth returns to normal.
Hydrocarbon contamination
No information Not relevant No information Not relevant
Insufficient
information
Radionuclide contamination
No information Not relevant No information Not relevant
Insufficient
information
Changes in nutrient levels
High Moderate Moderate Moderate
Fucus ceranoides was found to be absent from areas of high nutrient pollution in the Tyne estuary by Suryono & Hardy (1997). In low concentrations nutrients enhance the growth rate of the alga but in high concentrations growth is stopped. In general, fucoids recruit rapidly to cleared areas, but populations of this species are restricted to brackish waters so new individuals may have to recruit in from some distance.
Intermediate Moderate Moderate Moderate
Fucus ceranoides is adapted to living in brackish waters. It grows fastest at 11 psu and will die when exposed to freshwater for several weeks. Suryono & Hardy (1997) and Khfaji & Norton (1979) both found that vegetative branches of Fucus ceranoides died within 5-6 weeks when grown in fully saline water. However, Baeck et al., (1992) found that Fucus ceranoides survived and grew for 11 weeks in salinities of up to 45 psu.
No information
No information Not relevant No information Not relevant
Insufficient
information

Biological pressures

 IntoleranceRecoverabilitySensitivityEvidence/Confidence
No information Not relevant No information Not relevant
Insufficient
information
No information Not relevant No information Not relevant
Insufficient
information
No information Not relevant No information Not relevant
Insufficient
information
No information Not relevant No information Not relevant
Insufficient
information

Additional information

Importance review

Policy/legislation

- no data -

Status

Non-native

Importance information

-none-

Bibliography

  1. Baeck, S., Collins, J.C. & Russell, G., 1992. Recruitment of the Baltic flora: the Fucus ceranoides enigma. Botanica Marina, 35, 53-59.

  2. Barreiro, R., Real, C., Carballeira, A., 1993. Heavy-metal accumulation by Fucus ceranoides in a small estuary in north-west Spain. Marine Environmental Research, 36, 39-61.

  3. Fish, J.D. & Fish, S., 1996. A student's guide to the seashore. Cambridge: Cambridge University Press.

  4. Hardy, F.G. & Guiry, M.D., 2003. A check-list and atlas of the seaweeds of Britain and Ireland. London: British Phycological Society

  5. Howson, C.M. & Picton, B.E., 1997. The species directory of the marine fauna and flora of the British Isles and surrounding seas. Belfast: Ulster Museum. [Ulster Museum publication, no. 276.]

  6. JNCC (Joint Nature Conservation Committee), 1999. Marine Environment Resource Mapping And Information Database (MERMAID): Marine Nature Conservation Review Survey Database. [on-line] http://www.jncc.gov.uk/mermaid

  7. Khfaji, A.K. & Norton, T.A., 1979. The effects of salinity on the distribution of Fucus ceranoides. Estuarine, Coastal and Shelf Science, 8, 433-439.

  8. Lein, T.E., 1984. Distribution, reproduction and ecology of Fucus ceranoides L. (Phaeophyceae) in Norway. Sarsia, 60, 75-81.

  9. Norton, T.A. (ed.), 1985. Provisional Atlas of the Marine Algae of Britain and Ireland. Huntingdon: Biological Records Centre, Institute of Terrestrial Ecology.

  10. Suryono, C.A. & Hardy, F.G., 1997. Studies on the distribution of Fucus ceranoides L. (Phaeophyta, Fucales) in estuaries on the north-east coast of England. Transactions of the Natural History Society of Northumbria, 57, 153-168.

Citation

This review can be cited as:

White, N. 2007. Fucus ceranoides Horned wrack. In Tyler-Walters H. and Hiscock K. (eds) Marine Life Information Network: Biology and Sensitivity Key Information Reviews, [on-line]. Plymouth: Marine Biological Association of the United Kingdom. Available from: http://www.marlin.ac.uk/species/detail/1333

Last Updated: 03/07/2007