Ascidiella scabra

Researched By	Dr Keith Hiscock	Data Supplied By	MarLIN
Refereed by	This information is not refereed.
Taxonomy
Scientific name	Ascidiella scabra	Common name	A sea squirt
MCS Code	ZD85	Recent Synonyms	None
Phylum	Chordata	Subphylum	Tunicata
Superclass		Class	Ascidiacea
Subclass		Order	Enterogona
Suborder	Phlebobranchiata	Family	Ascidiidae
Genus	Ascidiella	Species	scabra
Subspecies
Additional Information	Specimens as large as 7.5 cm have been sampled from the Dogger Bank. Almost colourless examples can be found.
Taxonomy References	Lindsay & Thompson, 1930, Berril, 1950, Millar, 1970
General Biology
Growth form	Bullate / Saccate	Feeding method	Active suspension feeder
Mobility/Movement	Permanent attachment	Environmental position	Epibenthic, Epifaunal, Epilithic, Epifloral, Epiphytic, Epizoic
Typical food types	Suspended particles including phytoplankton	Habit	Attached
Bioturbator	Not relevant	Flexibility	High (>45 degrees)
Fragility	Fragile	Size	Small-medium(3-10cm)
Height	Up to 4 cm.	Growth Rate
Adult dispersal potential	None	Dependency	Independent
Sociability	Gregarious
Toxic/Poisonous?	No
Additional Information	Ascidiella scabra is usually about 2-3 cm in length although specimens from the Dogger Bank have been recorded at 7.5 cm in length (Lindsay & Thompson, 1930)
Biology References	Lindsay & Thompson, 1930
Distribution and Habitat
Distribution in Britain & Ireland	Present all around Britain and Ireland.
Global distribution	Present from the Faeroe Islands and Trondheimfjord in the north, occurring in the Kattegat and extending into the Mediterranean.
Biogeographic range	Not researched	Depth range	+2 - 300 m
Migratory	Non-migratory / Resident
Distribution Additional Information
Substratum preferences	Artificial (e.g. metal/wood/concrete), Bedrock, Large to very large boulders, Small boulders, Cobbles, Algae, Under boulders, Biogenic reef	Physiographic preferences	Open coast, Offshore seabed, Strait / sound, Sealoch, Ria / Voe, Estuary, Enclosed coast / Embayment
Biological zone	Sublittoral Fringe, Upper Infralittoral, Lower Infralittoral, Upper Circalittoral, Lower Circalittoral	Wave exposure	Moderately Exposed, Sheltered, Very Sheltered, Extremely Sheltered
Tidal stream strength/Water flow	Strong (3-6 kn), Moderately Strong (1-3 kn), Weak (<1 kn)	Salinity	Full (30-40 psu), Variable (18-40 psu)
Habitat Additional Information
AMBI Group (Borja et al., 2000)	III
Distribution References	Lindsay & Thompson, 1930, Millar, 1970, NBN, 2002
Reproduction/Life History
Reproductive type		Developmental mechanism
Reproductive Season	Insufficient information	Reproductive Location
Reproductive frequency	Annual protracted	Regeneration potential	No
Life span	3-5 years	Age at reproductive maturity	<1 year
Generation time	<1 year	Fecundity	Insufficient information
Egg/propagule size		Fertilization type
Larvae/Juveniles Larval/Juvenile dispersal potential 1km-10km Larval settlement period Duration of larval stage 2-10 days
Additional Information	Lindsay & Thompson (1930) noted the great fecundity of Ascidiella scabra and that eggs were produced (in the laboratory) from March onwards. Berrill (1950) notes that the species is oviparous, that the eggs are small (0.16 mm diameter) and sink in still water. Tadpole larvae emerge from eggs.
Reproduction References	Lindsay & Thompson, 1930, Berril, 1950