Tridacna derasa

giant clam

Tridacna derasa, Tobias Reef, Queensland, Australia, 1 of 2, Photo: Andrew Green

Tridacna derasa, Tobias Reef, Queensland, Australia, 2 of 2, Photo: Andrew Green

Tridacna derasa, Coral Sea, Australia, Photo: Ian Shaw

Tridacna derasa, Great Barrier Reef, Australia, Photo: Graham Edgar

Tridacna derasa, Rowley Shoals, Western Australia, Photo: Graham Edgar

Tridacna derasa, Flinders Reef, Coral Sea, Photo: Andrew Green

Tridacna derasa, Swains Reefs, Coral Sea 1 of 2, Photo: Andrew Green

Tridacna derasa, Swains Reefs, Coral Sea, 2 of 2, Photo: Andrew Green

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Same Genus

Tridacna sp. [cf noae]

Tridacna squamosa

Distribution

Description

Very symmetrical and smooth shell with many (6-7) ribs; mantle hardly extends beyond shell. Flat curves of the shell are distinctive (i.e. wavelength along shell edge is much greater than amplitude), particularly towards the ends. Mantle pattern often contains thin streaks or lines.

Information

Max Size: 52 cm

Sea Temperature Range: 21.2-30.4°C

Depth: N/A

Habitat Generalization Index: N/A

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: Vulnerable

Occurrence: Frequent (15.4% 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: Andrew Green

Further Information

Atlas of Living Australia IUCN Red List