MarLIN

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

An encrusting bryozoan (Oshurkovia littoralis)

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

Summary

Description

Colonies form large orange crusts that spread irregularly and are often fringed with green.

Recorded distribution in Britain and Ireland

Present all around the British Isles.

Global distribution

Present from Bergen, Norway south along the western Atlantic coast to at least the Channel Isles and western Brittany. Not present in the Mediterranean.

Habitat

A characteristic species of the sublittoral fringe and underboulder habitats. Occurs on rock and on Laminaria spp. holdfasts and Himanthalia elongata buttons.

Depth range

Intertidal to 6 m

Identifying features

  • Sheet-like encrusting form orange in colour.
  • Zooids 0.6 to 0.8 mm x 0.46 x 0.6 mm, oval to hexagonal bordered by raised lines.
  • Aperture of zooid elliptical.
  • Frontal wall finely granular with 14-20 large and conspicuous areolae.

Additional information

No text entered

Listed by

- none -

Further information sources

Search on:

Biology review

Taxonomy

PhylumBryozoa
ClassGymnolaemata
OrderCheilostomatida
FamilyUmbonulidae
GenusOshurkovia
Authority(Hastings, 1944)
Recent SynonymsUmbonula littoralis

Biology

Typical abundanceModerate density
Male size range
Male size at maturity
Female size rangeVery small(<1cm)
Female size at maturity
Growth formCrustose hard
Growth rateData deficient
Body flexibility
Mobility
Characteristic feeding methodActive suspension feeder, No information
Diet/food source
Typically feeds onSuspended material
Sociability
Environmental positionEpifaunal
DependencyIndependent.
SupportsNone
Is the species harmful?No information

Biology information

Umbonula littoralis is a hermaphrodite. The size range given above is for individual zooids.

Habitat preferences

Physiographic preferencesOpen coast, Strait / sound, Ria / Voe, Enclosed coast / Embayment
Biological zone preferencesSublittoral fringe, Upper infralittoral
Substratum / habitat preferencesBedrock, Cobbles, Large to very large boulders, 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 Strong > 6 knots (>3 m/sec.), Weak < 1 knot (<0.5 m/sec.)
Wave exposure preferencesExposed, Extremely exposed, Moderately exposed, Sheltered, Very exposed
Salinity preferencesFull (30-40 psu)
Depth rangeIntertidal to 6 m
Other preferencesNone
Migration PatternNon-migratory / resident

Habitat Information

No text entered

Life history

Adult characteristics

Reproductive typePermanent (synchronous) hermaphrodite
Reproductive frequency Annual protracted
Fecundity (number of eggs)No information
Generation timeInsufficient information
Age at maturityInsufficient information
SeasonJune - November
Life spanInsufficient information

Larval characteristics

Larval/propagule type-
Larval/juvenile development Lecithotrophic
Duration of larval stageNo information
Larval dispersal potential No information
Larval settlement period

Life history information

  • The dispersal phase is probably brief and larvae probably do not travel far.
  • Embryos were recorded as present in the Plymouth area in June and August (Marine Biological Association, 1957), from October and November on the north-east coast of England (Hastings, 1944) and from September to February in Manx waters (Eggleston, 1969).

Sensitivity reviewHow is sensitivity assessed?

Physical pressures

 IntoleranceRecoverabilitySensitivityEvidence/Confidence
High High Moderate Moderate
Removal of substratum will remove the attached species. However, larvae are produced annually and are likely to disperse from nearby unaffected substrata to recolonize.
Intermediate High Low Moderate
Smothering by overgrowth of competing encrusting ascidians may not kill Umbonula sp. (see Turner, 1988). Smothering by silt may however have an adverse effect. Larvae are produced annually and are likely to disperse from nearby unaffected substrata to recolonize.
Intermediate High Low Low
Umbonula lives in habitats that are generally clear of silt (exposed coasts and downward facing surfaces) but is likely to have at least limited ability to clear silt. Larvae are produced annually and are likely to disperse from nearby unaffected substrata to recolonize.
No information
Intermediate High Low Low
Umbonula lives in habitats that are in damp situations where it occurs on the lower shore suggesting that it would not survive desiccating conditions for very long. Larvae are produced annually and are likely to disperse from nearby unaffected substrata to recolonize.
Intermediate High Low Low
Umbonula lives in habitats that are in damp situations where it occurs on the lower shore suggesting that it usually requires submerged conditions. Increased amounts of emergence in desiccating situations are likely to lead to mortality. Larvae are produced annually and are likely to disperse from nearby unaffected substrata to recolonize.
No information
Intermediate High Low Low
Umbonula thrives in habitats that are in areas of strong water movement and is not generally found in sheltered areas suggesting that a decrease in water flow rates where wave action is also weak would be likely to result in mortality most likely as a secondary effect from siltation but possibly reduction in food source. Larvae are produced annually and are likely to disperse from nearby unaffected substrata to recolonize.
No information
Low High Low Low
The British Isles are at the centre of geographical range for Umbonula littoralis suggesting that colonies are likely to tolerate both warmer and colder conditions than those existing in Britain and Ireland. Larvae are produced annually and are likely to disperse from nearby unaffected substrata to recolonize.
No information
Low High Low
Increased turbidity may reduce phytoplankton production and therefore reduce food availability except where increased turbidity results from a plankton bloom.
No information
Intermediate High Low Low
Umbonula thrives in habitats that are in areas of strong water movement and is not generally found in sheltered areas suggesting that a decrease in wave exposure where tidal streams are also weak would be likely to result in mortality most likely as a secondary effect from siltation but possibly reduction in food source. Larvae are produced annually and are likely to disperse from nearby unaffected substrata to recolonize.
No information
Tolerant Not relevant Not sensitive Moderate
Umbonula is unlikely to sense noise but may be sensitive to vibration.
Tolerant Not relevant Not sensitive High
Umbonula may sense changes in light (shadowing) but has no visual organs.
Intermediate High Low Moderate
Umbonula has a hard calcareous skeleton which is likely to be broken through contact with hard surfaces such as cobbles moving around during storms. However, small portions of the colony might survive in irregularities of the substratum and spread after abrasion has ceased. Encrusting bryozoans occupy the zone above bare rock on abraded surfaces where there is a zonation from bare to dense erect growths (authors observations). Larvae are produced annually and are likely to disperse from nearby unaffected substrata to recolonize and so recoverability is recorded as high.
High High Moderate Low
Displacement of colonies off the substratum will result in mortality. Larvae are produced annually and are likely to disperse from nearby unaffected substrata to recolonize.

Chemical pressures

 IntoleranceRecoverabilitySensitivityEvidence/Confidence
No information Not relevant No information Not relevant
Insufficient
information.
Heavy metal contamination
No information Not relevant No information Not relevant
Insufficient
information.
Hydrocarbon contamination
Intermediate High Low Low
Ryland & DePutron (1998) observed no detectable damage to underboulder faunas affected by oil pollution in Watwick Bay, Pembrokeshire. These communities most likely included encrusting Bryozoa. However, it seems likely in the case of heavy pollution or pollution by light oils, damage may occur to encrusting bryozoans. Larvae are produced annually and are likely to disperse from nearby unaffected substrata to recolonize.
Radionuclide contamination
No information Not relevant No information Not relevant
Insufficient
information.
Changes in nutrient levels
No information Not relevant No information Not relevant
Insufficient
information.
High High Moderate Low
Umbonula littoralis appears to be restricted in distribution to areas that are continuously in full salinity conditions. It seems likely that variable or low salinity conditions will have an adverse effect. Larvae are produced annually and are likely to disperse from nearby unaffected substrata to recolonize.
No information
Low High Low
Umbonula littoralis probably survives overgrowth by encrusting ascidians as described by Turner (1988) suggesting that it can survive isolation from easily obtained oxygen. Larvae are produced annually and are likely to disperse from nearby unaffected substrata to recolonize.

Biological pressures

 IntoleranceRecoverabilitySensitivityEvidence/Confidence
No information Not relevant No information Not relevant
Insufficient
information.
No information Not relevant No information Not relevant
Insufficient
information.
Not relevant Not relevant Not relevant Not relevant
Insufficient
information.
High High Moderate Low
Kelp harvesting is removal of substratum (see above). Larvae are produced annually and are likely to disperse from nearby unaffected substrata to recolonize.

Additional information

Importance review

Policy/legislation

- no data -

Status

Non-native

Importance information

Umbonula littoralis is a characteristic species of the sublittoral fringe and of some biotopes.

Bibliography

  1. Eggleston, D., 1969. Marine fauna of the Isle of Man: revised lists of phylum Entoprocta (=Kamptozoa) and phylum Ectoprocta(=Bryozoa). Report of the Marine Biology Station Port Erin, 81, 57-80.

  2. Eggleston, D., 1972a. Patterns of reproduction in marine Ectoprocta off the Isle of Man. Journal of Natural History, 6, 31-38.

  3. Hastings, A.B., 1944. Notes on Polyzoa (Bryozoa). I. Umbonula littoralis auctt: U. ovicellata, sp.n. and U. littoralis, sp.n.. Annals & Magazine of Natural History, Series 11, Vol. 11, 273-284

  4. Hayward, P.J. & Ryland, J.S. 1979. British ascophoran bryozoans. London: Academic Press.

  5. 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

  6. MBA (Marine Biological Association), 1957. Plymouth Marine Fauna. Plymouth: Marine Biological Association of the United Kingdom.

  7. National Biodiversity Network (NBN) Atlas website. Available from: http://www.nbnatlas.org.  Accessed 01 April 2017

  8. Picton, B.E. & Costello, M.J., 1998. BioMar biotope viewer: a guide to marine habitats, fauna and flora of Britain and Ireland. [CD-ROM] Environmental Sciences Unit, Trinity College, Dublin., http://www.itsligo.ie/biomar/

  9. Turner, S.J., 1988. Ecology of intertidal and sublittoral cryptic epifaunal assemblages. II. Non-lethal overgrowth of encrusting bryozoans by colonial tunicates. Journal of Experimental Marine Biology and Ecology, 115, 113-126.

Citation

This review can be cited as:

Hiscock, K. 2005. Oshurkovia littoralis An encrusting bryozoan. 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/1347

Last Updated: 24/02/2005