BIOTIC

BIOTIC Species Information for Clavelina lepadiformis
All Taxonomy Biology Distribution Reproduction

Researched by	Karen Riley	Data supplied by	MarLIN
Refereed by	Dr Xavier Turon
General Biology
Growth form	Cylindrical	Feeding method	Active suspension feeder
Mobility/Movement	Permanent attachment	Environmental position	Epibenthic Epifaunal Epilithic
Typical food types	Suspended detritus and plankton	Habit	Attached
Bioturbator	Not relevant	Flexibility	Low (10-45 degrees)
Fragility	Fragile	Size	Small(1-2cm)
Height	Up to 2 cm.	Growth Rate	Insufficient information
Adult dispersal potential	None	Dependency	Independent
Sociability	Gregarious
Toxic/Poisonous?
General Biology Additional Information	The light bulb sea squirt grows to a maximum height of 20 mm (Fish & Fish, 1996; Picton, 1997). Colonies grow rapidly in spring and are full size after about two months (K. Hiscock, pers. comm.). The growth rate for settled specimens of Clavelina lepadiformis was found to be high (Tursi et al., 1977), although measures of growth rate were not found. Clavelina lepadiformis is an active suspension feeder, feeding on suspended detritus and plankton present in water passing through the branchial basket (Fish & Fish, 1996). It actively pumps water and can therefore thrive in very still conditions. The structure of the branchial sac for Clavelina lepadiformis is in its simplest form; the gill sheet is formed by a single screen with slits (Fiala-Medioni, 1978). Fiala-Medioni (1974) showed that filtration efficiency decreased with an increase in simplicity of this structure. The zooids of Clavelina lepadiformis are seldom fouled, other than at the base, either because of possible chemical defences or because of the delicate texture of its tunic (Teo & Ryland, 1994). Predators include bottom-feeding fish, carnivorous gastropods and starfish (Millar, 1970). Flatworms are also predators, Prostheceraeus moseleyi being a significant predator of Clavelina lepadiformis is the Mediterranean (X. Turon, pers. comm.). A study by de Caralt et al. (2002) revealed significant differences in certain aspects of the biology of Clavelina lepadiformis between harbour and open rocky littoral populations in the Mediterranean. Although no morphological differences were found, the abundance in the harbour populations were an order of magnitude higher than at the open littoral population. Furthermore, the harbour population did not experience aestivation (a period of inactivity and reduced metabolic activity), unlike the rocky littoral population, and reproduction also varied greatly. The littoral population only produced larvae for 2-3 months over winter and only had one gonadal cycle per year. By contrast, larvae were present in the harbour population from November to June with several gonadal cycles within this time. They concluded that there was marked ecotypic variation between populations of both habitat types and that the harbour population showed more opportunistic traits (Caralt et al., 2002).
Biology References	Fish & Fish, 1996, Millar, 1970, Teo & Ryland, 1995, Teo & Ryland, 1994, Steffan, 1991, Fiala-Medioni, 1978, Tursi et al., 1977, Picton & Costello, 1998, De Caralt et al., 2002, Tarjuelo et al., 2002,