BIOTIC Species Information for Didemnum spp.
Researched bySean Lindsley-Leake Data supplied byMarLIN
Refereed byThis information is not refereed
Scientific nameDidemnum spp. Common nameA colonial ascidian
MCS CodeZD48 Recent Synonyms

PhylumChordata SubphylumTunicata
Superclass ClassAscidiacea
Subclass OrderEnterogona
SuborderAplousobranchia FamilyDidemnidae
GenusDidemnum Species

Additional Information
Taxonomy References
General Biology
Growth form Feeding method
Mobility/MovementPermanent attachment
Environmental position
Typical food typesphytoplankton HabitAttached
Bioturbator FlexibilityLow (10-45 degrees)
FragilityIntermediate SizeSmall(1-2cm)
Height Growth Rate
Adult dispersal potential DependencyIndependent
General Biology Additional InformationOn collection all pores become invisible due to contraction of the colony, and the appearance changes considerably. 3mm thick x 10mm across as individual, large size from colonial mats up to 1m in size. They have the ability to attach tenaciously to substrates but the tunic is flaccid and tears easily. If even a small bit adheres to any organisms that are transported, it can rapidly colonize a new substrate and may already be in reproductive mode
Biology References Bullard et al, 2007, nurc website, Dias & Sergio de Almeida, 2004,
Distribution and Habitat
Distribution in Britain & IrelandFound on many British and Irish coasts, although rare in eastern Scotland, south-east England and much of Ireland.
Global distributionFound in north-west Europe from Norway to the Azores, in the Phillippines, off eastern Australia and New Zealand, and on west and east coasts of North America.
Biogeographic rangeTemperate to warm temperate. Depth range
Distribution Additional Information

Substratum preferences Physiographic preferences
Biological zone Wave exposure
Tidal stream strength/Water flow Salinity
Habitat Preferences Additional Information
Distribution References
Reproduction/Life History
Reproductive typePermanent hermaphrodite
Developmental mechanismLecithotrophic
Reproductive SeasonJuly to Sept Reproductive LocationWater column
Reproductive frequencyAnnual protracted Regeneration potential Yes
Life spanInsufficient information Age at reproductive maturity<1 year
Generation time<1 year Fecundityenvironmental variance
Egg/propagule size0.2mm Fertilization typeExternal
Larval/Juvenile dispersal potential100-1000m Larval settlement period<1day
Duration of larval stage<1 day   
Reproduction Preferences Additional InformationThe fecundity of these ascidians appears to be susceptible to water temperature, precipitation and other factors that vary yearly. Fecundity may also vary due to environmental differences among microhabitats.
Reproduction References Bullard et al, 2007, nurc website, Valentine et al., 2007, Dias & Sergio de Almeida, 2004, Hurlbut, 1991a,
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