Nocturnally active angel shark with a brown and white pattern
The Australian angelshark (Squatina australis) is a species of shark belonging to the family Squatinidae, found in the subtropical waters of southern Australia. They are perfectly camouflaged in brown and white, allowing them to lay motionless on the seabed waiting to ambush their prey. They can lay still for extended periods of time. Research suggests that their behavior changes at night and they may be nocturnally active.
Family: Squatinidae – Angel Sharks
Common Name– Angel Sharks or Angelsharks
Average Size and Length: Mature males are around 90 cm/ 3 feet. Mature females have been measured at 97 cm/ 3.2 feet. The maximum length is over 152 cm/ 5 feet. Research suggest males fully mature at 31 inches/ 2.6 feet.
Teeth and Jaw: They have expendable necks and trap-like jaws that can rapidly snap upwards and hinge shut. They have long, needle-like teeth in the upper and in the lower jaws used for gripping.
Head: The head of the Australian angelshark is flat. The area between the eyes is convex. There are 2 small spiracles. Each of these is set at a distance from the eye of about one and a half times the diameter of the eye. There are heavily fringed nasal barbels and anterior nasal flaps. There are no triangular lobes on the lateral head folds.
Denticles: There are no large thorns in the adults. The dermal denticles are enlarged on the snout and head. There are multiple pre-dorsal rows in young sharks.
Tail: The caudal fin is very short, nearly symmetrical but not lunate. Its lower lobe is slightly longer than the upper lobe.
Demographic, Distribution, Habitat, Environment and Range: The Australian angelshark can be found in the eastern Indian Ocean in southern Australia, including New South Wales (18°S – 41°S, 113°E – 150°E). They can be found in the sand and mud, even seagrass or close to rocky reefs between 49-840 feet. They are marine demersal preferring temperate seas.
Diet: They feed on fish and crustaceans.
Ram-Suction Index: They have an RSI more towards the suction end of the scale. They lay flat and still on the bottom, when the time comes, they lung at prey and suck it into their mouths with negative pressure.
Aesthetic Identification: The Australian angelshark has a broad, vertically compressed body. The Australian angelshark is much duller in color than some of its relatives. It is greyish-brown with dense white spots, and smaller darker brown spots. They have white-edged fins with spots on the leading edge of the pale dorsal fins and lower tail lobe. The pectoral fins are greatly enlarged, with a broad triangular lobe extending forward from their bases on either side of the gill slits. There are free trailing flaps. The pelvic fins are enlarged and wing-like. There are two small dorsal fins set far back.
Biology and Reproduction: The Australian angelshark is ovoviviparous, having up to 20 pups per litter in the autumn. Research suggests that the gestation period is around 10 months long.
Behavioral Traits, Sensing and Intelligence: The Australian angelshark lies semi-buried in the sand or on the muddy bottom waiting and ready to ambush prey. They can remain still on the bottom for extremely long and extended periods of time. Research suggest their behavior changes at night, and they are nocturnally active.
Australian angelsharks have a unique way of breathing compared to most other benthic sharks and fish. They do not pump out water from the oropharyngeal cavity. Instead, they use gill flaps located on the sides of their body to pump out water during respiration. Doing so also allows them to be more unnoticeable and prevent detection from unwanted predators.
Australian Angelshark Future and Conservation: They are commercially valuable, and have a limited range, but they are currently of least concern because their population appears to be large and stable. The reason why is their range is mostly unfished. It is occasionally trawled. The population has been monitored for 11 years from 1994 to 2004.
Australian Angelshark Recorded Attacks on Humans: Australian angelsharks aren’t dangerous to humans unless provoked. Because of their powerful jaws and sharp teeth, they can inflict injury on anyone or anything that may pose a threat to them. There have been cases of Angel sharks biting divers that have tried to restrain them, approach too close to the head, corner them, or grab their tails.