Colour

Other colours Cliona have been described as range from the more common dark brown with obvious yellow oscula (Vacelet et al. 2008) to yellow, dark greyish-brown, bright yellow to orange (C. celata) and the less common purple cliona’s such as C.schmidti, C. purpurea and C. tinctoria, which are the only three species so far to be found in this colour (Schonberg 2000).

Size and Form

Due to its encrusting nature, size range is variable and is dependent on how large the surface area of the substrate is, as it aims to overtake most of the substrate. It is possible that light availability also affects the size of sponges as a result of its symbiotic relationship with zooxanthellae. This also suggesting why it is found in shallow depths (Lopez-Victoriaand Zea 2005; Schonberg 2002).  

Upon lateral spread, the encrusting, excavating form of Cliona produces a shallow depression of approximately 1-2cm deep into the substrate. They can expand from a few centimetres to several meters wide depending on the substrates surface area (Lopez-Victoria and Zea 2005; Schonberg 2002).

Growth form of various Cliona, dictates size and location. For example sponges without symbiotic zooxanthellae such as C. aprica, requires less light therefore can be found in deeper waters and may be more cryptic within its substrate rather than be light exposed (Lopez-Victora and Zea 2005, Schonberg 2002).

Once the sponge has overtaken the surface of the substrate and no longer has space to spread laterally, the sponge tissue begins to thicken (Lopez-Victoria and Zea 2005).

Further information

Detailed descriptions of sponge characteristics useful for identification of common Great Barrier Reef Cliona’s including C. celata, C.orientalis and C. tinctoria can be found in reference to Schonberg, C.H., 2000.Bioeroding sponges common to the central Australian Great Barrier Reef:Descriptions of three new species, two new records and additions to two previously described species. Senckenbergiana maritima, 30, 161-221.