Australian Blacktip Shark

About the Australian Blacktip Shark

The Australian Blacktip Shark, is a species of requiem shark endemic to Australian waters. It is found mainly in tropical and temperate waters along the northern and eastern parts of Australia, with its known range from Thevenard Island in Western Australia to Sydney in New South Wales.

Biology and Description

The Australian Blacktip Shark has a moderately robust body and a long, pointed snout. The anterior rims of the nostrils are slightly enlarged into triangular flaps. Its eyes are equipped with nictitating membranes. There are 32 to 35 upper tooth rows, with a slender upright cusp, and 29 to 31 lower tooth rows, which are narrower and more finely serrated. The five pairs of gill slits are long. The pectoral fins are sickle-shaped with pointed tips.

The first dorsal fin is falcate and originates above the rear portion of the pectoral fin bases. The second dorsal fin is tall and positioned approximately opposite the anal fin. The caudal fin is asymmetrical, with a strong lower lobe and a longer upper lobe. The dermal denticles are diamond-shaped, closely arranged together and almost overlapping. The species is bronze or greyish-bronze on its back and whitish on its belly.

Australian blacktip sharks typically reach between 1.5 and 1.8 m (4.9–5.9 ft) long. The maximum recorded length and weight are of 2.0 m (6.6 ft) and 23.6 kg (52 lb).

Reproduction

This species is viviparous, which means embryos develop inside the uterus and are nourished through a placental connection. The average litter size is 3 pups, with litters ranging from 1 to 6 young. Their length at birth is around 60 cm (23.6 in) and pups are born in January after a 10 month gestation period. These sharks breed once each year. Males reach maturity at approximately 110 cm (43.3 in) in length, while females mature at 115 cm (45.3 in).

Habitat

Larger sharks tend to occur in deeper water. Tagging studies have found this species mostly moves only short distances along the coastline and rarely enters offshore waters. However, some individuals have been recorded travelling longer distances.

Conservation

Together with the Spottail Shark, Carcharhinus sorrah, the Australian Blacktip Shark is an important species in several northern Australian commercial fisheries. It is caught both intentionally and as bycatch, and it is used for its meat and fins. However, the species is classified as Least Concern by the IUCN because its population has recovered after fishing pressure decreased and management measures were introduced.

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