Zebra SharkStegostoma fasciatum
This stout coastal carpetshark is torpedo-shaped, with ridges that run down its flanks to its very long caudal (tail) fin. It has a rounded snout and small eyes, rounded pectoral fins, small dorsal fins, and a small mouth with teeth made for crunching mollusks. Adults are light yellow-brown and covered in dark spots, while the juveniles are quite dark with white bars across their bodies. They are considered harmless to humans, and are popular attractions for dive tourism and public aquariums.
Order - Orectolobiformes
Family - Stegostomatidae
Genus - Stegostoma
Species - fasciatum
English language common names are zebra shark, leopard shark, and variegated shark. Other common names include bagea oneone (Gela), butanding (Bikol), cá nhám nhu mí (Vietnamese), chalarm-sue-dao (Thai), chkuot (Khmer), chlarm (Khmer), corootoolti-sorrah (Telugu), coruhgun-sorrah (Tamil), corungum sorrah (Tamil), cucut poto (Malay), cucut tekeh (Malay), farluuq shabeellow (Somali), hitha miyaru (Maldivian), komarasi (Telugu), komarasi-sorrah (Tamil), komrasi (Telugu), kooseh-e-Goor-e-khari (Persian), korangum sorrah (Tamil), magara (Gujarati), mangra (Sindhi), moemoeao (Samoan), mushi (Marathi), musia (Gujarati), nirééré (Carolinian), orookoolti-sorrah (Telugu), pating (Tagalog), pazifischer Zebrahai (German), pollee makum (Telugu), poochasurav (Malayalam), potrava (Telugu), rekin brodaty (Polish), requin tigre (French), requin zèbre (French), sebrahaai (Afrikaans), sebrahaj (Swedish), shinavla (Marathi), shinawala (Gujarati), shinvala (Gujarati), ta'aneva (Samoan), talakitiki (Visayan), thalab al bahar (Arabic), tiburón acebrado (Spanish), torafu zame (Japanese), torafuzame (Japanese), tubarão-zebra (Portuguese), wolaaliy (Carolinian), yu chechak (Malay), yYu chechok (Malay), yu kebut (Malay), yu tokeh (Malay), zebra sravu (Malayalam), zebrahaai (Dutch), zebrahai (German), and zebrahaj (Danish).
Importance to HumansThis shark is of only minor interest to commercial fisheries although it is considered a gamefish by recreational fishers. The zebra shark is often taken as bycatch in drift nets intended for other targeted species. It is sometimes marketed fresh or dried-salted for human consumption, as well as for use in fishmeal. The fins are dried and sold in the asian sharkfin market.
Zebra sharks are also used in a number of display aquarium facilities around the world as they adapt quite readily to captivity. They are easily approached by scuba divers as long as a safe distance is maintained.
Danger to Humans
They are generally harmless to humans however, they may bite if provoked. There has been one documented unprovoked attack on a human according to the International Shark Attack File, however this attack resulted in no injuries.
Zebra sharks are susceptible to declines in population due to inshore fishery activities and coral reef habitat loss because of its limited habitat preference and geological distribution. It is listed as "Vulnerable" by the World Conservation Union (IUCN) throughout most of its range. In Australia it is considered "Least Concern" due to its abundance in this area. The IUCN is a global union of states, governmental agencies, and non-governmental organizations in a partnership that assesses the conservation status of species.
Geographical DistributionThe zebra shark resides in the Indo-West Pacific Ocean in the Red Sea and off East Africa, north to southern Japan and south to New South Wales (Australia). There has also been a recent record of a zebra shark from the waters of Tonga and there is one unconfirmed report of a zebra shark residing in fresh water in the Philippines.
A tropical, inshore species, the zebra shark lives on sand, rubble, and coral bottoms at depths from 0-207 feet (0-63 m). Due to its sluggish behavior during daylight hours, it is believed to be a nocturnal species. It is often observed sitting on the bottom in close proximity to coral reefs. This small shark has been recorded in marine and brackish waters as well as in freshwater habitats.
The zebra shark has a moderately stout, cylindrical body with prominent ridges running along the dorsal surface and on the flanks. The head has five small gill slits with the last three slits located behind the origins of the pectoral fins. The nostrils are close to the front of the rounded snout which has short barbels. The nasoral grooves connect the nostrils with the mouth. The spiracles are as large as the eyes. The large pectoral fins are broadly rounded. The first dorsal fin is larger than the second dorsal fin. The rear tip of the first dorsal fin is close to the origin of the second dorsal fin. Both dorsal fins lack spines. The caudal fin is very long, reaching lengths close to the size of the rest of the body. It has a deep subterminal notch however the lower lobe lacks much development.
The body is yellow-brown with dark brown spots while the young (smaller than 70 cm in length) are dark in color with white spots and stripes, fading to a pale ventral surface. These stripes are what give this species its common name of zebra shark. The adults have longitudinal skin ridges which are absent in young individuals.
The dentition is similar in both jaws with 28-33 teeth in the upper jaw and 22-34 in the lower jaw. These teeth are small and each has three cusps (tricuspid).
The maximum reported size of a male zebra shark is 7.7 feet (2.35 m) total length and the maximum size of a female is 7.6 feet (2.33 m) total length. Sexual maturity is obtained at lengths of 5.6 feet (1.70 m). The lifespan of the zebra shark is believed to be 25-30 years in the wild; shorter lifespans can be expected for zebra sharks that are maintained in small aquariums.
This small shark feeds primarily on mollusks as well as small bony fishes that it sucks out of the sand. Other prey items include crabs and shrimp. It also swims slowly and squirms into narrow crevices and channels in reefs in search of prey.
The zebra shark is an oviparous species meaning that it releases egg cases into the environmental where they are anchored to the bottom substrate by hair-like fibers. The egg cases of this shark are large and dark brown or purplish black with longitudinal striations, measuring 6.7x3.1x2 inches(17x8x5 cm). When the young emerge, they measure approximately 7.9-10 inches (20-26 cm) total length.
Potential predators of the zebra shark include larger bony fish and sharks as well as marine mammals.
At least four species of tapeworm (Pedibothrium spp.) are documented parasites of the zebra shark.
Hermann originally described the zebra shark as Squalus fasciatus in 1783. However that name was later changed to the currently valid Stegostoma fasciatum (Hermann 1783). The genus name, Stegostoma, is derived from the Greek stego meaning 'cover' and stoma meaning 'mouth'. It is the only species within its genus. Synonyms referring to this species in past scientific literature include Squalus longicaudus Gmelin 1789, Scyllia quinquecornuatum Van Hasselt 1823, Scyllium heptagonum Rüppell 1837, Stegostoma carinatum Blyth 1847, Squalus cirrosus Gronow 1854, Stegostoma varius Garmin 1913, Stegostoma varium Garmin 1913, Stegastoma varium Graman 1923, and Stegostoma tigrinum naucum Whitley 1939.
Prepared by: Cathleen Bester