Trinorfolkia clarkeiCommon threefin | Norfolkia clarkei
Pink or brown body with a prominent stripe below the eye. Mostly distributed in coastal reef habitats, the species also occurs in estuaries, where it is often found around jetty pylons. Two almost identical species with similar colouration and a stripe below the eye have also been recorded from the south coast. Trinorfolkia incisa, a very small species (<30 mm) found between Esperance and Wilsons Promontory, has a first dorsal fin with the webbing between the spines deeply indented. The rare SA species Trinorfolkia cristata has a first dorsal fin higher than the second; in T. clarkei it is lower.
Max Size: 8 cm
Sea Temperature Range: 10.4-23.3°C
Depth: 0-30 m
Habitat Generalization Index: 10.2
Also referred to as the SGI (Species Generalisation Index), this describes the habitat niche breadth of the species. Species with values less than 15 are found in a relatively narrow range of reef habitat types (specialists), while those over 25 may be found on most hard substrates within their range (generalists). Learn more here.
Conservation and Rarity
IUCN Status: Not Evaluated
Occurrence: Common (36.1% of sites)
Occurrence describes how often the species is found on surveys within its distribution. It is calculated as the % of reef sites surveyed by RLS divers across all the ecoregions in which the species has been observed
Abundance: Few (2 per transect)
Abundance is calculated as the average number of individuals recorded per RLS transect, where present.
Edit by: GJ Edgar. 2008. Australian Marine Life. New Holland, Sydney