GREAT HAMMERHEAD SHARK

Sphyrna mokarran
Family: Sphyrnidae

Description: Light grey or grey-brown in color with white ventral countershading. Very large cephalofoil (hammerhead) with a notch at the center of its head. Tall, large first dorsal fin, small second dorsal with long trailing edge.

Distribution and Habitat: Population distributed worldwide in tropical and warm temperate waters. Occurs in coastal-pelagic and semi-oceanic waters. Found around continental shelves, island terraces, lagoons, and coral reefs both close to and far off shore. Depth can range from 0-300 meters.

Size: Maximum size reported at 610 cm total length, more commonly observed max size of around 400 cm total length. Size at birth is typically 50-70 cm total length.

Reproduction: Aplacental viviparity with litter sizes of 6-42 pups. Gestation period is 11 months on a biennial cycle. Males have been found to reach sexual maturity around 225-269 cm total length, and females mature around 210-300 cm total length.

Life span: Estimated at 44 years in the Northwest Atlantic.

Diet: Primarily feeds on batoids such as southern stingrays (Hypanus americanus) and spotted eagle rays (Aetobatus narinari), as well as bony fishes.
IUCN Status: Critically endangered.

Human pressures: Targeted and caught as bycatch globally in commercial and small-scale fisheries by many different gear types: longline, purse seine, gillnets, and trammel nets. Great hammerheads are usually retained for their fins unless prohibited. At-vessel and post-release mortality rate is high for this species regardless of method of capture.