Leopard shark (Stegostoma fasciatum)
|Also known as:||zebra shark|
|Size||Length: 2.40 – 3.50 m (2)|
Classified as Vulnerable (VU) on the IUCN Red List. In Australia, it is classified as Least Concern (LC) (1).
The leopard shark is an immediately recognisable, stunningly attractive species, which derives its common name from its distinctive markings of dark brown leopard-like spots set against a yellow-brown skin tone (2). Juveniles, which are less than 70 centimetres in length, can be distinguished from adults by their markedly different colouration. This consists of narrow white stripes and blotches contrasted against a dark brown base colour, from which its alternative common name of ‘zebra shark’ arises (3) (4). Adults also have prominent longitudinal skin ridges that are lacking in young (5). This shark has a cylindrical body with large pectoral fins, two close-set spineless dorsal fins and a very long caudal fin, almost as long as the rest of the body (2). There are five gill slits on the sides of its broad head (6). Harmless to man, this beautiful shark is approachable, especially during the day as it rests on the seabed (3).
The leopard shark is found over continental and insular shelves in warm temperate to tropical areas of the Indian Ocean (including the Red Sea and the Arabian Gulf) and west Pacific Ocean. The leopard shark is more abundant in Australian waters than in other parts of its range, as it is not exploited to the same extent as it is elsewhere (2) (6).
Leopard sharks inhabit shallow inshore and offshore waters near the bottom, at depths down to around 62 metres, often found close to coral reefs (1). Recorded to have entered freshwater in the Philippines but this needs to be confirmed (5).
These sharks are mostly solitary (6) but can occasionally be found in aggregations of 20 to 50 individuals (1). Believed to be a nocturnal hunter, they spend most of the day lazily swimming and resting on the bottom (5), becoming active at night when they hunt for sleeping fish, molluscs and crustaceans (3). A slow but powerful swimmer, leopard sharks have unusually flexible bodies that are used to squirm into tiny crevices in search of food (5) (6).
Female leopard sharks lay large, purplish-black eggs, which they anchor to the floor with many long hair-like fibres (7). It is likely that more than one egg is laid at a time. Once hatched, the young are independent of their mother (6). Males reach sexual maturity once they reach a size of between 1.5 and 1.8 metres and females at around 1.7 metres (8). The life-span of leopard sharks in the wild is not exactly known, but it is thought that they may live for an average of 25 years (6).
There is no direct evidence of a decline in leopard shark numbers but Indo-West Pacific surveys of local fish markets suggest it is much less common than it used to be. Incidental and deliberate capture by fishing companies is the principal threat to the leopard shark across its range outside Australia; it can be found in fish markets all around Indonesia, Thailand, Malaysia, the Philippines, Pakistan, Taiwan and India (1). The liver is used to make vitamins and its fins are dried for the Oriental shark-fin trade to be used in soups (6) (8). Threats in Australia are minimal. Evidence from the Gulf of Thailand show it was historically more abundant and may have been affected by the use of explosives and poisons on reefs (1).
There are currently no conservation measures in place for this species (1).
For further information on the conservation of sharks and rays see:
Authenticated by Dr. Colin Simpfendorfer (31/03/08) Director of Fishing and Fisheries Research Centre, James Cook University, Australia.
- Caudal fin: the tail fin of a fish, used for steering, balancing or propulsion.
- Crustaceans: diverse group of arthropods (a phylum of animals with jointed limbs and a hard chitinous exoskeleton) characterised by the possession of two pairs of antennae, one pair of mandibles (parts of the mouthparts used for handling and processing food) and two pairs of maxillae (appendages used in eating, which are located behind the mandibles). Includes crabs, lobsters, shrimps, slaters, woodlice and barnacles.
- Dorsal fin: in fish, one of the unpaired fins found on the back of the body.
- Molluscs: a diverse group of invertebrates, mainly marine, that have one or all of the following; a horny, toothed ribbon in the mouth (the radula), a shell covering the upper surface of the body, and a mantle or mantle cavity with a type of gill. Includes snails, slugs, shellfish, octopuses and squid.
- Nocturnal: being active at night.
- Pectoral fins: in fish, the pair of fins that are found one on each side of the body just behind the gills. They are generally used for balancing and braking.
IUCN Red List (December, 2009)