An encrusting bryozoan (Oshurkovia littoralis)
Oshurkovia littoralis
Photographer: Keith Hiscock Copyright: Dr Keith Hiscock
Distribution data supplied by the Ocean Biodiversity Information System (OBIS). To interrogate UK data visit the NBN Atlas.Map Help
| Researched by | Dr Keith Hiscock | Refereed by | Dr Peter J. Hayward |
| Authority | (Hastings, 1944) | ||
| Other common names | - | Synonyms | Umbonula littoralis |
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 mIdentifying 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 -
Biology review
Taxonomy
| Phylum | Bryozoa | Sea mats, horn wrack & lace corals |
| Class | Gymnolaemata | Naked throat bryozoans |
| Order | Cheilostomatida | |
| Family | Umbonulidae | |
| Genus | Oshurkovia | |
| Authority | (Hastings, 1944) | |
| Recent Synonyms | Umbonula littoralis | |
Biology
| Typical abundance | Moderate density | ||
| Male size range | |||
| Male size at maturity | |||
| Female size range | Very small(<1cm) | ||
| Female size at maturity | |||
| Growth form | Crustose hard | ||
| Growth rate | Data deficient | ||
| Body flexibility | |||
| Mobility | |||
| Characteristic feeding method | Active suspension feeder, No information | ||
| Diet/food source | |||
| Typically feeds on | Suspended material | ||
| Sociability | |||
| Environmental position | Epifaunal | ||
| Dependency | Independent. | ||
| Supports | None | ||
| 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 preferences | Open coast, Strait / sound, Ria / Voe, Enclosed coast / Embayment |
| Biological zone preferences | Sublittoral fringe, Upper infralittoral |
| Substratum / habitat preferences | Bedrock, Cobbles, Large to very large boulders, Small boulders |
| Tidal strength preferences | Moderately 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 preferences | Exposed, Extremely exposed, Moderately exposed, Sheltered, Very exposed |
| Salinity preferences | Full (30-40 psu) |
| Depth range | Intertidal to 6 m |
| Other preferences | None |
| Migration Pattern | Non-migratory / resident |
Habitat Information
No text enteredLife history
Adult characteristics
| Reproductive type | Permanent (synchronous) hermaphrodite | |
| Reproductive frequency | Annual protracted | |
| Fecundity (number of eggs) | No information | |
| Generation time | Insufficient information | |
| Age at maturity | Insufficient information | |
| Season | June - November | |
| Life span | Insufficient information |
Larval characteristics
| Larval/propagule type | - |
| Larval/juvenile development | Lecithotrophic |
| Duration of larval stage | No 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 review
The MarLIN sensitivity assessment approach used below has been superseded by the MarESA (Marine Evidence-based Sensitivity Assessment) approach (see menu). The MarLIN approach was used for assessments from 1999-2010. The MarESA approach reflects the recent conservation imperatives and terminology and is used for sensitivity assessments from 2014 onwards.
Physical pressures
| Intolerance | Recoverability | Sensitivity | Evidence/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
| Intolerance | Recoverability | Sensitivity | Evidence/Confidence | |
| No information | Not relevant | No information | Not relevant | |
| Insufficient information. | ||||
| No information | Not relevant | No information | Not relevant | |
| Insufficient information. | ||||
| 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. | ||||
| No information | Not relevant | No information | Not relevant | |
| Insufficient information. | ||||
| 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
| Intolerance | Recoverability | Sensitivity | Evidence/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
| National (GB) importance | - | Global red list (IUCN) category | - |
Non-native
| Native | - | ||
| Origin | - | Date Arrived | Not relevant |
Importance information
Umbonula littoralis is a characteristic species of the sublittoral fringe and of some biotopes.Bibliography
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.
Eggleston, D., 1972a. Patterns of reproduction in marine Ectoprocta off the Isle of Man. Journal of Natural History, 6, 31-38.
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
Hayward, P.J. & Ryland, J.S. 1979. British ascophoran bryozoans. London: Academic Press.
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
MBA (Marine Biological Association), 1957. Plymouth Marine Fauna. Plymouth: Marine Biological Association of the United Kingdom.
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.
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.
Datasets
Centre for Environmental Data and Recording, 2018. Ulster Museum Marine Surveys of Northern Ireland Coastal Waters. Occurrence dataset https://www.nmni.com/CEDaR/CEDaR-Centre-for-Environmental-Data-and-Recording.aspx accessed via NBNAtlas.org on 2018-09-25.
Environmental Records Information Centre North East, 2018. ERIC NE Combined dataset to 2017. Occurrence dataset: http://www.ericnortheast.org.ukl accessed via NBNAtlas.org on 2018-09-38
Fenwick, 2018. Aphotomarine. Occurrence dataset http://www.aphotomarine.com/index.html Accessed via NBNAtlas.org on 2018-10-01
Kent Wildlife Trust, 2018. Biological survey of the intertidal chalk reefs between Folkestone Warren and Kingsdown, Kent 2009-2011. Occurrence dataset: https://www.kentwildlifetrust.org.uk/ accessed via NBNAtlas.org on 2018-10-01.
Kent Wildlife Trust, 2018. Kent Wildlife Trust Shoresearch Intertidal Survey 2004 onwards. Occurrence dataset: https://www.kentwildlifetrust.org.uk/ accessed via NBNAtlas.org on 2018-10-01.
Manx Biological Recording Partnership, 2018. Isle of Man historical wildlife records 1990 to 1994. Occurrence dataset:https://doi.org/10.15468/aru16v accessed via GBIF.org on 2018-10-01.
NBN (National Biodiversity Network) Atlas. Available from: https://www.nbnatlas.org.
OBIS (Ocean Biodiversity Information System), 2023. Global map of species distribution using gridded data. Available from: Ocean Biogeographic Information System. www.iobis.org. Accessed: 2023-03-28
Yorkshire Wildlife Trust, 2018. Yorkshire Wildlife Trust Shoresearch. Occurrence dataset: https://doi.org/10.15468/1nw3ch accessed via GBIF.org on 2018-10-02.
Citation
This review can be cited as:
Last Updated: 24/02/2005
