Epaulette SharkHemiscyllium ocellatum
This carpet shark got its name from the large black spots with white margins just above its pectoral fins which look like decorations on a military uniform. It is a long, slender shark, with rounded fins and an asymmetrical, elongated caudal (tail) fin. They tend to be creamy or brown, with widely spaced brown spots, but as juveniles also have several dark saddle-like bands for camouflage. They often forage for food in tidal pools and risk being stranded, so they can survive several hours out of water, and even crawl small distances on their muscular pectoral fins.
Order - Orectolobiformes
Family - Hemiscylliidae
Genus - Hemiscyllium
Species - ocellatum
English language common names include epaulette shark, blind shark, and itar shark. Other common names are almindelig epaulethaj (Danish), bamboa ocellada (Spanish), epaulethaai (Dutch), lyhtytetra (Finnish), requin-chabot ocellé (French), and sokkopartahai (Finnish).
Importance to Humans
The epaulette shark is quite docile and easy to approach without risk of injury. Beachcombers can easily catch this species due to its clumsy manner of movement over the bottom substrate and its preference for shallow water habitats. When caught, it will squirm but doesn't cause any harm to its captors other than perhaps a nip, but itself is often harmed in the ordeal. It is often displayed in public aquarium facilities in the US, Canada, and Australia due to its high rates of survival in captivity. It is of no interest to commercial or recreational fisheries at this time.
Danger to Humans
The epaulette shark is considered harmless to humans although it may bite if handled.
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 epaulette shark is found in the western Pacific Ocean in waters around New Guinea and northern Australia. Off the coast of Australia, this shark is found from Shark Bay in Western Australia around the northern coast south to Newcastle and perhaps even to Sydney, New South Wales. The epaulette shark may also reside off Malaysia, Sumatra (Indonesia), and the Solomon Islands, however these reports need to be confirmed.
Commonly found in shallow water coral reef habitats from 0-164 feet (0-50 m) in depth, this bottom-dwelling shark is able to "walk" along the sea floor with muscular pectoral fins. The epaulette shark is also often found caught in tide pools cut off by the receding tide and exposed reef flats. It is well adapted for survival in these low-oxygen habitats by turning off non-essential bodily functions for several hours. One scientific study determined that the blood pressure of an epaulette shark dropped 50% during conditions of hypoxia.
The epaulette shark is a small, slender shark with a short snout. It has an oronasal groove connecting the subterminal mouth to the nostrils and small nasal barbels. The two spineless dorsal fins are similar in size and are located on posterior on the body. The anal fin is located just anterior to the tail. The precaudal tail is elongated and thick. The pectoral and pelvic fins are broadly rounded and paddle-like. Modifications of the attachment of these fins to the body allow for a dramatically increased range of motion. This allows this shark to use these fins to move over the substrate in a "walking" type of motion. The caudal fin has a subterminal notch and lacks a ventral lobe.
In Australian waters, the family Hemiscyllidae includes the epaulette shark and the speckled carpet shark (H. trispeculare). The epaulette shark can be distinguished from the speckled carpet shark by the presence of small dark spots located immediately behind the ocellus of the speckled carpet shark. The epaulette shark lacks these spots.Coloration
The body is cream-colored or brownish with numerous widely spaced brown spots. There are two large black spots surrounded by a white margin located above the pectoral fins. These look like ornamental epaulettes on a military uniform, giving rise to its common name. Juvenile epaulette sharks have several darker brown saddles extending as dark crossbands on the back and tail which are lost, turning into spots, as they reach maturity. This coloration provides protective camouflage with their natural environment.
The teeth are similar in each jaw and are small, broad-based, and narrowly triangular cusps.
The maximum size of the epaulette shark is 42.1 inches (107 cm) total length. Males reach maturity at 23.6 inches (60 cm) total length while females reach maturity at 25.2 inches (64 cm) total length.
The epaulette shark feeds at dusk and at dawn, often in tide pools. The senses of electroreception and olfaction are relied upon when searching for food. Benthic invertebrates provide prey for this shark. In the waters off Australia, crustaceans and segmented worms make up the majority of the adult epaulette shark diet. Juveniles feed predominantly on polychaete worms. The snout is sometimes used to overturn bottom debris in search for hidden worms and crustaceans. When feeding on hard-shelled prey, this shark's sharp teeth flatten to form crushing plates making it possible for it to feed on such items. The epaulette shark often chews on its food for quite sometime before ingesting it.
The reproductive mode of the epaulette shark is oviparous. During mating, the male grasps the female by biting the body and the gill region. The female later releases paired ellipsoid egg cases into the aquatic environment. Each female may release up to 50 eggs annually. These egg cases measure approximately 3.9 inches (10 cm) in length and 1.6 inches (4 cm) in width and hatch after about 120 days. When the young emerge, each measures around 5.9 inches (15 cm) in length. Growth is slow, measuring about 1.2 inches (3 cm) during the first year.
Larger fish including other sharks are potential predators of the epaulette shark.
Parasites of the epaulette shark include the praniza larvae of gnathiid isopods. These are found near the cloaca and clasper regions as well as the buccal and brachial cavities. However, it is believed that these parasites cause no harm to the overall health of the host shark.
Bonnaterre originally described the epaulette shark as Squalus ocellatus in 1788. This name was later changed to the currently valid Hemiscyllium ocellatum (Bonnaterre 1788). The genus name, Hemiscyllium, is derived from the Greek 'hemi' meaning half and 'skylla' translated as a kind of shark. The epaulette shark is a member of the family Hemiscyllidae, often referred to as the longtail carpet sharks. One synonym, Squalus oculatus Banks & Solander 1827, has appeared in past scientific literature referring to this species.
Prepared by: Cathleen Bester