Smooth hammerhead shark (Sphyrna zygaena) B A
D
C C
Scientific Classification: Species Identification:
Class: Chondrichthyes (fish with cartilogenous skeletons) Morphology: Order: Carcharhiniformes A). Hammerhead shape head that bugles forward but has no central Family: Sphyrnidae indentation Genus: Sphyrna B). Large rigid triangular dorsal fin Species: S. zygaena C). Relatively short penctoral fins (Bonnaterre, 1788). D). Small secondary dorsal fin E). Long upper tail lobe
Distribu tion: Teeth: -Very broad cusps with slightly serrated edges.
Colouration: Greyish dorsal colouration.
Size: Adults reach a maximum length of 5 meters. Males (1.7m) ♂ are smaller than females ♀ (2.2 m). Pups born between 50–61 cm.
Most tolerant hammerhead species to temperate water, and occurs worldwide to higher latitudes than any other species. In the Atlantic, it occurs from Nova Scotia to the Virgin Islands and from Brazil to southern Argentina in the west, and from the British Isles to Côte Biology d'Ivoire, including the Mediterranean Sea. In Northern Europe, there are only six confirmed records from the British Isles, and one record for Irish waters as of June 2019, recorded during a Marine Institute Thermoregulation: survey in the Celtic Sea. Hammerhead sharks are ectothermic animals which must use heat acquired from the environment and behavioral adaptations to Ecology: regulate body temperature.
Reproduction: Habitat: Compared to the scalloped and great hammerheads, the Males become mature at 2.1–2.5 m, while females at 2.7 m. Like smooth hammerhead stays closer to the surface, in water less than other hammerheads, the smooth hammerhead is viviparous: once 20 m deep. However, it has been recorded diving to a depth of 200 m. the young exhaust their supply of yolk, the empty yolk sac is Prefers inshore waters, such as bays and estuaries, but is sometimes converted into a placental connection through which the mother found in the open ocean over the continental shelf, and around delivers nourishment. Females bear relatively large litters of 20– oceanic islands. In the summer, smooth hammerheads migrate 50 pups after a gestation period of 10–11 months. Birthing occurs poleward to stay in cooler water, heading back towards the equator in in shallow coastal nurseries. winter. Adult sharks may form small groups during migrations and juveniles form massive shoals. Lifespan: 20+ years
Diet: an active-swimming predator that feeds on bony fishes, rays, sharks (including of its own species), cephalopods, and to a lesser extent crustaceans such as shrimp, crabs, and barnacles. They readily scavenge from fishing lines., Copyright ©O.R.C.Ireland2019.