Common thresher shark (Alopias vulpinus) A B

C D C

Scientific Classification: Species Identification:

Class: Chondrichthyes (fish with cartilogenous skeletons) Morphology: Order: Lamniformes A). Heterocerecal caudal fin, with elongated dorsal lobe Family: Alpoiidae B). Small convex shaped snout Genus: Alpoias C). Large dorsal and pectoral fins Species: A.vulpinus D). Large anal fins (Bonnaterre, 1788). Teeth: - 40 small blade-like teeth in upper jaw, 20 each side and 42 in lower Distribu tion: jaw, with 21 each side.

Colouration: Grey, brown, blue or blackish dorsally, ventrally white- above pectoral fins.

Size: Adults reach a maximum length of 7.5 meters (usually up to 3m). Males (4.5 m) ♂ are larger than females ♀ (3.3 m). Pups born between 114- 160 cm.

Almost global distribution, found in tropical and cold temperate seas. In Biology the East Atlantic thresher sharks are distributed from Norway to Cape Province, South Africa, and the Mediterranean Sea. Thermoregulation: Thresher sharks are endothermic; metabolic heat generated by its Ecology: red muscles is conserved within the body by specialized systems of blood vessels called retia mirabilia (Latin for "wonderful nets"; Habitat: Thresher sharks are found in both continental waters and singular rete mirabile), that act as highly the open ocean. They tend to be most abundant in proximity to land, efficient countercurrent heat exchangers. particularly the juveniles, which frequent near-coastal habitats such as

bays. The species has been described as "coastal–oceanic", mostly Reproduction: occurring within 30 km of the coast with considerably lower Males become mature at 3.3 m or 5 years of age, while females at populations beyond this limit. Most individuals are encountered near 2.6–4.5 m (6.6–7.2 ft) and an age of 7 years. The common the surface, but this species has been recorded to at least a depth of thresher has an aplacental viviparous mode of reproduction, 550 m. Among eight individuals tagged and tracked for 22–49 hours with oophagous embryos that feed on undeveloped off southern California, all spent the majority of their time within 40 m eggs ovulated by their mother. Females typically give birth to four of the water surface, but periodically dived much deeper, in five pups at a time, following a gestation period of nine months. New individuals to depths of around 100 m. Prefer water temps of 16 and borns can weigh 5-6 kg and the juveniles grow about 50 cm a 21 °C. year, while adults grow about 10 cm a year. Diet: bony fishes, small schooling forage fish such

as mackerel, bluefish, herring, needlefish, and lanternfish. Before Lifespan: 45-50 years. striking, they compact schools of prey by encircling them and

splashing the water with their tails, often in pairs or small groups. They use the long upper lobes of their tail fins to stun prey, and they are often snagged on longlines by their tails after presumably striking at Copyright ©O.R.C.Ireland2019. the bait.