Invasive Species Compendium

Detailed coverage of invasive species threatening livelihoods and the environment worldwide


Schizoporella errata
(branching bryozoan)



Schizoporella errata (branching bryozoan)


  • Last modified
  • 20 November 2018
  • Datasheet Type(s)
  • Invasive Species
  • Preferred Scientific Name
  • Schizoporella errata
  • Preferred Common Name
  • branching bryozoan
  • Taxonomic Tree
  • Domain: Eukaryota
  •   Kingdom: Metazoa
  •     Phylum: Bryozoa
  •       Class: Gymnolaemata
  •         Order: Cheilostomatida
  • Summary of Invasiveness
  • Schizoporella errata is a heavily calcified, encrusting cheilostome bryozoan. It colonises most freely available substratum, including artificial underwater st...

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Preferred Scientific Name

  • Schizoporella errata (Waters, 1878)

Preferred Common Name

  • branching bryozoan

Other Scientific Names

  • Lepralia errata

International Common Names

  • English: cheilostome bryozoan; encrusting bryozoan

Summary of Invasiveness

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Schizoporella errata is a heavily calcified, encrusting cheilostome bryozoan. It colonises most freely available substratum, including artificial underwater structures and vessel hulls. Colonies may reach 25cm in height and are widely varying in growth form, sometimes dominating space in fouling assemblages.

Taxonomic Tree

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  • Domain: Eukaryota
  •     Kingdom: Metazoa
  •         Phylum: Bryozoa
  •             Class: Gymnolaemata
  •                 Order: Cheilostomatida
  •                     Family: Schizoporellidae
  •                         Genus: Schizoporella
  •                             Species: Schizoporella errata


Top of page Schizoporella errata is typically dark brick red with orange-red growing margins. This species may form heavy knobbly encrustations on flexible surfaces such as algae or worm tubes, turning them into solid, sometimes erect branching structures. The thickness of the growth is dependent upon the age of the colony. Multilaminar encrustations of 1cm thick are common. The frontal surface of the zoecium (secreted exoskeleton housing of individual zooids) is porous with a wide semicircular aperture and proximal sinus. avicularia (beak-like structures) occur in varying density on colonies, located (one per zooid) to the right or left side of aperture sinus. Bleached specimens show the skeletal features clearly. Preserved specimens lose their colour.
S. errata forms massive colonies with variously shaped colony forms. Forms are determined by interactions with other organisms and hydrodynamic conditions. At exposed sites, colonies form a densely packed mass with no branching, while in calmer waters colonies are erect, highly branched and have thicker bases (Morgado and Tanaka 2001).


Top of page Native range: The native distribution of Schizoporella errata is ascribed to the Mediterranean (Hewitt et al. 2004; Bishop Museum 2002). This designation should be regarded as cursory until taxonomic issues are resolved, and the possibility of early unrecognised introductions is explored.
Known introduced range: S. errata is a common fouling organism worldwide and has been reported from West Africa, the Red Sea, the Persian Gulf, Australia, New Zealand, Hawaiian Islands, the Pacific coast of North America and the East coast of North America through the Caribbean to Brazil (Bishop Museum 2002).

Distribution Table

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The distribution in this summary table is based on all the information available. When several references are cited, they may give conflicting information on the status. Further details may be available for individual references in the Distribution Table Details section which can be selected by going to Generate Report.

Continent/Country/RegionDistributionLast ReportedOriginFirst ReportedInvasiveReferenceNotes

Sea Areas

Atlantic, Western CentralPresentIntroduced Invasive ISSG, 2011
Indian Ocean, WesternPresentIntroduced Invasive ISSG, 2011


ChinaPresentIntroduced Invasive ISSG, 2011
IsraelPresentIntroduced Invasive ISSG, 2011


EgyptPresentIntroduced1977 Invasive ISSG, 2011
West AfricaPresentIntroduced Invasive ISSG, 2011

North America

USAPresentPresent based on regional distribution.
-CaliforniaPresentIntroduced Invasive ISSG, 2011
-HawaiiPresentIntroduced1693 Invasive ISSG, 2011
-New HampshirePresentIntroduced Invasive ISSG, 2011
-South CarolinaPresentIntroduced Invasive ISSG, 2011
-WashingtonPresentIntroduced Invasive ISSG, 2011

South America

BrazilPresentIntroduced Invasive ISSG, 2011


CroatiaPresentNativeISSG, 2011
GermanyPresentIntroduced Invasive ISSG, 2011
GreecePresentNativeISSG, 2011
ItalyPresentNativeISSG, 2011
SpainPresentNative Invasive ISSG, 2011
UKPresentIntroduced Invasive ISSG, 2011


AustraliaPresentIntroduced1982 Invasive ISSG, 2011
-Western AustraliaPresentIntroduced Invasive ISSG, 2011
Midway IslandsPresentIntroduced Invasive ISSG, 2011
New ZealandPresentIntroduced Invasive ISSG, 2011
VanuatuPresentIntroduced Invasive ISSG, 2011


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S. errata is usually found in harbours and embayments in shallow water on hard substrates (pilings, hulls, coral rubble, etc.) and reefs (Bishop Museum, 2002). In southeastern Brazil it occurs in shallow (0–10m) water attached to rocks or pier columns. S. errata occurs mainly in calm waters and is one of few bryozoans that occur in water of the pleiomesohaline region (water salinity around 18-8%) (Winston, 1977).

Habitat List

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Marine Present, no further details Harmful (pest or invasive)

Biology and Ecology

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Bryozoans are suspension feeders with retractable U-shaped crowns of tentacles (lophophores) that bear cilia. The movement of cilia create small currents that bring microscopic prey (plankton) and organic particles toward the animal. The particles are then guided into the mouth by action of the tentacles and cilia    

Each bryozoan colony begins from a single, sexually produced, primary zooid. Schizoporella zooids bud in lines, forming unilaminar, bilaminar or multilaminar sheets. Like most bryozoans, Schizoporella are hermaphroditic. Each zooid is capable of producing sperm and eggs. Larvae are brooded in an external ovicell. Larvae are cilliated and non-feeding and attach and metamorphose within 1 or 2 days following release. S. errata larval settlement occurs throughout the year, except during midwinter (Sutherland and Karlson 1977). Cummings (1975) described zooidal regression and regeneration in colonies of S. floridana, suggesting a potentially important life history response to seasonal changes in temperature and food availability.

New recruits of S. errata are vulnerable to predation immediately (hours to days) after metamorphosis and attachment to the substrate. Experiments show that predators such as the small gastropod Mitrella lunata can result in a high mortality (around 50%) by feeding exclusively on the first zooid or ancestrula of each S. errata colony (Osman and Whitlatch 2004).

Lifecycle stages
Bryozoans have swimming, lecithotrophic larvae that attach and metamorphose within 1 or 2 days following release from the colony. Larvae colonise a variety of artificial substrata including hulls (Mackie et al. 2006).

The new recruits of S. errata are vulnerable to predation immediately (hours to days) after metamorphosis and attachment to the substrate. Experiments show that predators such as the small gastropod Mitrella lunata can result in a high mortality (around 50%) by feeding exclusively on the first zooid or ancestrula of each S. errata colony (Osmana and Whitlatch 2004).

Means of Movement and Dispersal

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Introduction pathways to new locations
Aquaculture:Schizoporella errata / unicornis introductions have been reported in association with oyster transport (Carlton 1989; PWSRCAC 2004; Fuller 2007).
Ship ballast water:
Ship/boat hull fouling:Schizoporella errata occurs on vessel hulls (Ryland 1965). Allen (1953) reported the spread of a Schizoporella (referred to as S. ‘unicornis’, but possibly S. errata) in association with vessel fouling to ports in southern Australia during the 1940s.

Local dispersal methods
Natural dispersal (local):

Pathway Causes

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CauseNotesLong DistanceLocalReferences
Aquaculture Yes

Pathway Vectors

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VectorNotesLong DistanceLocalReferences
Aquaculture stock Yes
Ship ballast water and sediment Yes
Ship hull fouling Yes


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General Impacts
Compiled by IUCN SSC Invasive Species Specialist Group (ISSG)

Bryozoans are one of the main groups of fouling organisms that form encrustations on ships, piers, buoys and other man-made structures in oceans (VMNH 2005). Exotic species may compete for space with natives. Schizoporella errata is known to inhibit the growth of adjacent species (Sutherland and Karlson 1977), Introductions in some areas could potentially contribute to community productivity by providing substratum. In southeastern Brazil S. errata forms colonies of up to 25cm in height and supply a diverse range of secondary structure used by cryptic faunal species, including polychaetes, crustaceans and echinoderms (Nalesso et al. 1995; Duarte and Nalesso 1996 in Morgado and Tanaka 2001).

S. errata has a high recruitment rate over the summer months and is common on pilings. In the US Atlantic, Sutherland (1978) noted colonies were particularly common in areas of space that are regularly cleared by urchin grazing; larvae appear to be relatively inefficient at recruiting into established fouling communities.

Risk and Impact Factors

Top of page Impact mechanisms
  • Competition
  • Fouling

Similarities to Other Species/Conditions

Top of page There is extensive confusion in distinguishing Schizoporella species and a clear need to examine the systematics of the group at a global scale.
Schizoporella unicornis occurs in the North East Atlantic, from the Faroe Islands and western Norway south to north-west Africa, the western Mediterranean. It is believed to be the same species as the form found on the Atlantic coast of North America, north of Cape Cod (Hayward and Ryland 1979). Further south, S. errata is common, however confusion exists with other described species, in particular Schizoporella floridana (Osburn, 1914) which occurs from occurring from Beaufort, North Carolina south to Florida, the Gulf of Mexico and the Caribbean – this taxon may be a distinct species or variant of S. errata (Ryland 1965; Winston 1982).

Reports of introductions are mired by difficulties in distinguishing S. unicornis (Johnston, in Wood 1854), a species described from European Atlantic, and S. errata (Waters, 1878), which may be native to the red-sea or Mediterranean. The zooid aperture is the principal character distinguishing these two species: the aperture of S. unicornis is broader than long, while the S. errata aperture is approximately equal in length and breadth (Ryland, 1968).

Schizoporella errata is widespread in warm temperate-subtropical areas, occurring from the west coast of Africa, the Persian Gulf and the Pacific and Atlantic coasts of America (Hayward and Ryland). Allen (1953) reported that a schizopellid (referred to as ‘S. unicornis’) spread from a Pacific location to Ports in the vicinity of Sydney and Perth, Australia during the 1940s. The species found throughout Australian ports at present appears to be S. errata (Mackie pers. comm. 2007).

Prevention and Control

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Management Information
Compiled by IUCN SSC Invasive Species Specialist Group (ISSG)
Preventative measures: A two-year study was undertaken for the Department of Environment and Heritage (Australia) by the Commonwealth Scientific and Industrial Research Organisation (CSIRO) to identify and rank introduced marine species found within Australian waters and those not found within Australian waters.
All of the non-native potential target species identified in this report are ranked as high, medium and low priority, based on their invasion potential and impact potential. Schizoporella errata is identified as one of ten potential domestic target species most likely to be spread to uninfected bioregions by shipping. S. errata is also identified as one of ten most damaging potential domestic target species, based on overall impact potential (economic and environmental). A hazard ranking of potential domestic target species based on invasion potential from infected to uninfected bioregions identifies S. errata as a 'medium priority species' - these species have a reasonably high impact/or invasion potential.
For more details, please see Hayes et al. 2005.
The rankings determined in Hayes et al. 2005 will be used by the National Introduced Marine Pest Coordinating Group in Australia to assist in the development of national control plans which could include options for control, eradication and/or long term management.
Ballast water control measures can help control the spread of Schizoporella errata from the oyster aquaculture industry (PWSRCAC 2004). Cu (copper) based antifouling coatings on boat hulls can prevent growth of S. errata and stop its spread to new locations (Piola and Johnston 2006).


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Allen, F. E. 1953. Distribution of marine invertebrates by ships. Australian Journal of Marine and Freshwater Research 4: 303-316.

Bishop Museum. 2002. Schizoporella errata (Waters, 1878), Guidebook of introduced marine species of Hawaii. Hawaii Biological Survey, Bishop Museum.

Bock, P. 2000. Schizoporella cf. errata (Waters, 1878). RMIT University: Melbourne.

Carlton, J.T. 1989. Man's role in the changing face of the ocean: Biological invasions and implications for conservation of near-shore environments. Conservation Biology 3(3):265-273.

Centre for Environment, Fisheries & Aquaculture Science (CEFAS)., 2008. Decision support tools-Identifying potentially invasive non-native marine and freshwater species: fish, invertebrates, amphibians.

Cocito, S. 2004. Bioconstruction and biodiversity: their mutual influence, Scientia Marina 68 (Suppl.1): 137-144.

Cocito, S. Ferdeghini, F.. Morri, C. and Bianchi, C.N. 2000. Patterns of bioconstruction in the cheilostome bryozoan Schizoporella errata: the influence of hydrodynamics and associated biota, Marine Ecology Progress Series 192: 153-161.

Cummings, S. G. 1975. Zoid regression in Schizoporella unicornis floridana (Bryozoa, Cheilostomata), Chesapeake Science 16:93-103

Fuller, P. 2007. Schizoporella unicornis. USGS Nonindigenous Aquatic Species Database, Gainesville, FL.

Ghobashy, A.F.A. and El Komy, M.M. 1980. Fouling in the southern region of the Suez Canal, Aquatic Ecology 14(3): 179-185.

Hayes, K., Sliwa, C., Migus, S., McEnnulty, F., Dunstan, P. 2005. National priority pests: Part II Ranking of Australian marine pests. An independent report undertaken for the Department of Environment and Heritage by CSIRO Marine Research.

Hayward, P. J. and Ryland, J. S. 1979. British Ascophoron Bryozoans. London: Academic Press.

Hayward, P.J. 1974. Studies on the cheilostome bryozoan fauna of the Aegean island of Chios, Journal of Natural History 8(4): 369-402

Henderson, R.S. 1986. Effects of Organotin Antifouling Paint Leachates on Pearl Harbor Organisms: A Site Specific Flowthrough Bioassay, Oceans 18: 1226-1233

Hewitt, C. L, Campbell, M. L., Thresher, R. E., Martin, R. B., Boyd, S., Cohen, B. F., Currie, D. R., Gomon, M. F., Keough, M. J., Lewis, J. A., Lockett, M. M., Mays, N., McArthur, N., O'Hara, T. D., Poore, G. C. B., Ross, J. D., Storey, M. J., Watson, J. E. and Wilson, R. S. 2004. Introduced and crytogenic species in Port Phillip Bay, Victoria, Australia. Marine Biology 144: 183-202.

Jara, V.C., Miyamoto, J.H.S., da Gama, B.A.P., Molis, M., Wahl, M. and Pereira, R.C. 2006. Limited evidence of interactive disturbance and nutrient effects on the diversity of macrobenthic assemblages, Marine Ecology Progress Series 308: 37-48.

Mackie, J.A., Keough, M.J. and Christidis, L. 2006. Invasion patterns inferred from cytochrome oxidase I sequences in three bryozoans, Bugula neritina, Watersipora subtorquata, and Watersipora arcuata, Marine Biology 149: 285-295

McKinney, F. K. and McKinney, M. J. 2002. Contrasting marine larval settlement patterns imply habitat-seeking behaviours in a fouling and a cryptic species (phylum Bryozoa), Journal of Natural History 36: 487-500.

Morgado, E.H. and Tanaka, M.O. 2001. The macrofauna associated with the bryozoan Schizoporella errata (Walters) in southeastern Brazil, Scientia Marina 65(3): 173-181.

NEMESIS (National Exotic Marine and Estuarine Species Information System). 2006. Schizoporella errata. Retrieved 19 December, from Chesapeake Bay Introduced Species Database.

Osman, R.W. & Whitlatch, R.B. 2004. The control of the development of a marine benthic community by predation on recruits, Journal of Experimental Marine Biology and Ecology 311: 117-145.

Perkol-Finkel, S. and Benayahu, Y. 2004. Recruitment of benthic organisms onto a planned artificial reef: shifts in community structure one decade post-deployment. Article in press.

Piola, R.F. and Johnston, E.L. 2006. Differential resistance to extended copper exposure in four introduced bryozoans, Marine Ecology Progress Series 311: 103-114.

Prince William Sound Regional Citizens' Advisory Council. 2004. Non-indigenous Aquatic Species of Concern for Alaska. Fact Sheet 9. Single Horn Bryozoan.

Reichert, K. 2002. Tentaculata Bryozoa (dt. Moostierchen) Iris Menn.

Ryland, J. S. 1965. Volume 2: Polyzoa. In Catalogue of main marine fouling organisms (found on ships coming into European Waters). OECD.

Ryland, J. S. 1968. On marine polyzoa III. Schizoporella ansata auctt. Journal of Natural History 2: 535-546.

Sutherland, J.P. 1978. Functional Roles of Schizoporella and Styela in the Fouling Community at Beaufort, North Carolina, Ecology 59(2): 257-264.

Sutherland, J.P. and Karlson, R.H. 1977. Development and Stability of the Fouling Community at Beaufort, North Carolina, Ecological Monographs 47(4): 425-446.

Tao Yan and Wen Xia Yan. 2002. Fouling of Offshore Structures in China–a Review. Biofouling 19 (Supplement): 133-138

United States Geological Survey. 2007. Schizoporella errata. USGS Nonindigenous Aquatic Species Database, Gainesville, FL.

Virginia Museum of Natural History (VMNH), 2005. More Bryozoan Information. VMNH Virginia, USA.

Winston, J. E. 1982. Marine bryozoans (Ectoprocta) of the Indian River area (Florida). Bulletin of the American Museum of Natural History 173: 102-176.

Winston, J.E. 1977. Distribution and Ecology of Estuarine Ectoprocts: A Critical Review, Chesapeake Science18(1): 34-57.

Wyatt, A.S.J., Hewitt, C.L., Walker, D.I. and Ward, T.J. 2005. Marine introductions in the Shark Bay World Heritage Property, Western Australia: a preliminary assessment, Diversity and Distributions 11(1): 33-44

Links to Websites

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GISD/IASPMR: Invasive Alien Species Pathway Management Resource and DAISIE European Invasive Alien Species Gateway source for updated system data added to species habitat list.
Global register of Introduced and Invasive species (GRIIS) source for updated system data added to species habitat list.


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    Reviewed by: Dr. Josh Mackie, Invertebrate Zoology and Molecular Ecology Lab. Moss Landing Marine Laboratories. California USA
    Compiled by: IUCN/SSC Invasive Species Specialist Group (ISSG) with support from La Fondation d'entreprise Total
    Last Modified: Wednesday, May 23, 2007


Distribution Maps

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