August Elasmobranch of the Month: Spot-Tail Shark
Author: Linda Weiss
The Spot-tail shark is a medium sized shark, averaging 160 cm (5.2 ft) in length. They are a thinner shark, with a relatively long, rounded snout. They are grayish-brown on top and cream to white underneath. The tips of their lower caudal fin, the second dorsal fin and their pectoral fins display black tips. While their first dorsal fin and the upper lobe of the caudal fin have black edges. The second dorsal fin is significantly smaller than the first and is located near the caudal fin. An interdorsal ridge is not present. The teeth in both the upper and lower jaws are serrated and triangular. Those in the lower jaw are narrower and more pointed compared to the upper jaw.
Habitat and Distribution
The Spot-tail shark is a tropical Indo-Pacific species that ranges from South Africa to China and Australia, including Madagascar, India, Malaysia, and the Philippines. This shark’s habitat includes continental and insular shelves, sand and mud bottoms as well as coral reefs. It can be found at depths ranging from 20 – 140 m (66 – 459 ft), most commonly found inshore in the 20 – 50 m (66 – 164 ft) range.
The Spot-tail’s diet consists crustaceans, fish, squid and octopus.
Spot-tail shark reproduction takes place once a year. Gestation is 10 months long and results in the live birth of 1 - 8 pups per litter (average 3), with each pup measuring approximately 50 cm (19.7 inches) long. This species uses viviparous reproduction where embryos develop inside the female nourished by a placental yolk sac.
The IUCN Red List of Threatened Species currently lists the Spot-tail shark as Near Threatened, with an unknown population trend. An assessment update is needed as the last assessment was made in July 2007.
Spot-tail sharks are targeted by the commercial fishing industry for their meat and fins. Like many other shark species, they are also caught as bycatch in trawls, gillnets, and on longlines. Some nursery areas are also negatively impacted by habitat destruction.
Credit: Fishbase- Tassapon Krajangdara
Sustainable Fisheries Partnership (SFP). Spottail shark Northern Territory. FishSource profile. In: FishSource [online]. Accessed [10 August 2021]. https://www.fishsource.org/stock_page/1936
The IUCN Red List of Threatened Species
Pillans, R., Stevens, J.D. & White, W.T. 2009. Carcharhinus sorrah. The IUCN Red List of Threatened Species 2009: e.T161376A5409506. https://dx.doi.org/10.2305/IUCN.UK.2009-2.RLTS.T161376A5409506.en. Downloaded on 10 August 2021