Sphyrna lewini

Scalloped Hammerhead
Sphyrna lewini
Sphyrna lewini, Photo: Graham Edgar


Mediterranean, Temperate Africa, Temperate Australasia, Temperate South America, Temperate northern Atlantic, Temperate northern Pacific, Tropical Atlantic/Caribbean, Tropical Eastern Pacific, Tropical Indo-Pacific


Noticeable indentation in middle of \'hammer\' distinguishes it from S. mokarran (great) and S. zygaena (smooth) hammerheads.


Max Size: 430 cm

Sea Temperature Range: 19-30.2°C

Depth: 1-500m

Habitat Generalization Index: 2.08

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: Endangered

Occurrence: Common (28.7% 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 (4 per transect)

Abundance is calculated as the average number of individuals recorded per RLS transect, where present.

Edit by: extract from RD Stuart-Smith, GJ Edgar, AJ Green, IV Shaw. 2015. Tropical Marine Fishes of Australia. Reed New Holland