The inhalant anterior opening into the gut is larger and terminal with eight lobes while the atrial siphon is smaller and shorter with six lobes (McDonald, 2004). Larvae are free swimming and tadpole-like in appearance, with a dorsal nerve cord, a rudimentary brain and a notochord (Holland, 2002). After dispersal, larvae attach to a surface with their head after which the tail is reabsorbed and metamorphosis into a sessile filter-feeding adult occurs (Holland, 2002).

Once settled, C. intestinalis provide a poor substrate for other settlers, producing strong anti-microbial compounds that may restrict epibiosis and therefore limit recruitment of other species (Finslay & Smith, 1995; in Blum et al, 2007). The maximum reported lifespan of individuals is 2 years, but a more typical lifespan is 1 year (Jackson, 2000; in Blum et al, 2007).

Additionally, as a highly competitive species within subtidal, epibenthic communities, C. intestinalis has also displaced native species, lowered biodiversity, and altered community properties in some invaded habitats (Blum et al 2007; Therriault & Herborg, 2008b).

Preventative measures: A risk assessment carried out by Hayes et al (2005) in Australia determined that C. intestinalis was one of top ten species in both its likelihood to be spread to uninfected bioregions by shipping and its damage potential. Preventative requirements on Prince Edward Island, Canada failed to stop the spread of C. intestinalis (Locke et al., 2009b). The only regulated vector in Canada is ballast water coming in from commercial shipping (Locke et al., 2009a)

Monitoring: Tunicate collectors were created and used to detect the presence and distribution of exotic tunicate species in the Bay of Fundy, including Ciona intestinalis (LeGresley et al, 2008).

Physical control: Aquaculture farmers surveyed by Clancey & Hinton (2003) revealed that physical removal methods such as hand scrubbing, scraping or high pressure spraying were the most common treatments used to remove tunicates that had become established on gear, however C. intestinalis quickly re-established populations within short periods.

Chemical control: A number of chemical treatments to control C. intestinalis have been trialed (Carver et al, 2003). While some like acetic acid and calcium hydroxide have shown promising results, chemicals have the potential to alter estuarine pH are and have been shown to be biocidal to a variety of non-target organisms such as species of bacteria, shrimp and fish (Locke et al, (2009b).

Biological control: Potential biological control agents include the rock crab, Cancer irroratus and green crab, Carcinus maenas. The use of crab predators for the control of C. intestinalis in aquaculture is limited for a number of reasons (Carver et al, 2003). Grazing species such as Littorina littorea and the shrimp Rhynchocinetes typus have also been trialled, with the shrimp in particular showing promising results (Dumont et al., 2009).

Cultural control: These refer to aquaculture management practices and generally include avoiding times of high C. intestinalis recruitment, changing or rotating the gear used or air drying depending on the species being farmed and the gear being used. More information on C. intestinalis recruitment patterns and population development is necessary to develop more effective management procedures (Ramsay, et al, 2009).