PYJAMA SHARK OR STRIPED CATSHARK
Of course, it’s nocturnal, always wearing its pyjamas!
The Pyjama shark or Striped catshark (Poroderma africanum) is a species of catshark belonging to the family Scyliorhinidae. It is endemic to the coastal waters of South Africa. It has an unmistakable appearance, having a series of thick, parallel, dark stripes running along its body. It is a nocturnal, bottom-dwelling species found in the intertidal zone over kelp beds and rocky reefs.
Family: Scyliorhinidae – Catsharks
Common Name– Ground Sharks
Common Name– Catsharks
Average Size and Length: Hatchlings measure around 14-15 cm/5.5-5.9 inches. Mature males have been measured between 58-76 cm/1.9-2.5 feet. Mature females have been measured between 65-72 cm/2.1-2.4 feet. The maximum recorded has been 95 cm/3.1 feet. One record now claims 101 cm/3.3 feet.
Current Rare Mythical Sightings: The Pyjama shark was originally described as Squalus africanus by German naturalist Johann Friedrich Gmelin in 1789, in the thirteenth edition of Systema Naturae. He did not designate a type specimen. In 1837, Scottish physician and zoologist Andrew Smith created the new genus Poroderma for this species and the related Leopard catshark (P. pantherinum, at the time believed to be multiple species). In 1908, the Pyjama shark was made the type species of the genus by American zoologist Henry Weed Fowler.
Teeth and Jaw: The mouth is large, and forms a broad arch, with short furrows extending from the corners onto both the upper and lower jaws. The upper teeth are exposed when the mouth is closed. There are 18–25 and 14–24 tooth rows on either side of the upper and lower jaws. They have longer, slender pointed teeth with three cusps, with the central cusp much longer than the two surrounding, the two surrounding cusplets are extremely small, they are almost not visible to the eye. The teeth of adult males are slightly thicker than those of females.
Head: The head and snout are short and slightly flattened, with a narrowly parabolic outline when viewed from above or below. Each nostril is split into tiny incurrent and excurrent openings by a flap of skin in front; the flap has a three-lobed shape with the central lobe forming a long, conical barbel, which are prominent but short. The eyes are horizontally oval and placed rather high on the head, with nictitating membranes and a thick ridge running underneath.
Denticles: The skin is very thick and has well-calcified dermal denticles. Each denticle has an arrowhead-shaped crown with three posterior points, mounted on a short stalk.
Tail: The short and broad caudal fin has an indistinct lower lobe and a ventral notch near the tip of the upper lobe.
Demographic, Distribution, Habitat, Environment and Range: The Pyjama shark or Striped catshark can be found in the southeast Atlantic and western Indian Ocean. They are apparently endemic to South Africa in both Capes and on rare occasion KwaZulu-Natal. There are apparent sightings in a few other locations, but these need verification. They are found on the continental shelf to the upper slope from the surf line and intertidal zone to 925 feet, often in shallow areas. They are on or near the bottom in rocky areas and in kelp beds, often found in caves. They are considered demersal.
It favors cephalopods and frequents the spawning grounds of the Chokka squid (Loligo reynaudi). Mass spawning events occur unpredictably year-round but peak from October to December. During this time, they deviate from their nocturnal habits and gather in substantial numbers inside the squids’ “egg beds” during daytime. The sharks conceal their heads amongst the egg masses, while their stripes break up the outlines of their bodies. As the female squid descend to the sea floor to attach their eggs, guarded by the males, they become vulnerable.
They have also been known to scavenge on fish offal. In False Bay the Cape rock lobster (Jasus lalandii) is the most important food source, followed by cephalopods and then fish. Pyjama sharks have been observed seizing and tearing off tentacles from octopus and cuttlefish with a twisting motion; on one occasion three sharks were seen attacking an octopus simultaneously.
They do fall prey to larger sharks. It is one of the cartilaginous fish most frequently consumed by the Broadnose Sevengill shark (Notorynchus cepedianus). Its eggs are fed upon by the whelks Burnupena papyracea and B. lagenaria, which can pierce the outer covering to extract the yolk within.
Aesthetic Identification: The Pyjama shark or Striped catshark has unmistakable longitudinal, think, parallel stripes numbering in between 5-7. They are striking black or dark brown or dark greyish against a light brown, almost white background. The stripes become broken near the tail and the belly. In some sharks, the main stripe on either side may fork behind the eye, the stripes may be split in two by lighter central lines, or one or more large dark spots may be present. The underside is pale, sometimes with light gray spotting, and clearly defined from the flank color. Young sharks resemble the adults, but may be much lighter or have much darker stripes. There are no spots. The body is stout in shape. The body is fairly compressed from side to side and tapers towards the tail. There are prominent dorsal fins, with the second dorsal fin much smaller. They are set very far back on the body. The first dorsal fin originates over the rear of the pelvic fins while the second originates over the midpoint of the anal fin. The pectoral fins are large and broad. The pelvic fins are lower than the pectorals but their bases are about equal in length. Adult males have a pair of short, thick claspers, with the inner margins of the pelvic fins partially fused over them to form an apron.
An albino specimen has been recorded from False Bay.
Biology and Reproduction: They are oviparous. They lay pairs of egg cases, one per oviduct, year-round. One hatched in an aquarium after 5.5 months. Each egg case is rectangular and dark brown in color. Each egg case measures 9.5 cm/3.7 inches long and 4.5 cm/1.8 inches across, with long tendrils at the corners that enable the female to fasten the capsule to underwater structures such as algae stipes or gorgonians.
Like other sharks, the Pyjama shark maintains osmotic balance with the environment by regulating its internal concentration of urea and other nitrogenous wastes. Experiments have shown that the shark’s capacity for osmoregulation is dependent on how well it has fed. (Martin, R.A. Kelp Forests: Pyjama Catshark. ReefQuest Centre for Shark Research).
Behavioral Traits, Sensing and Intelligence: They are nocturnal, but have been spotted sometimes active during the day. It spends most of the day lying motionless and hidden in a cave or crevice or among vegetation like kelp forests. It often forms groups, particularly during summer. When threatened, it curls into a circle with its tail covering its head.
Speed: They are slow-swimming.
Pyjama Shark or Striped Catshark Future and Conservation: They are currently near threatened. They have been taken for aquaria because of their small size and striking appearance, and are robust in captivity. They have also been taken by trawlers and anglers. It is often caught as a bycatch of commercial and recreational fisheries. Many are killed by fishers who regard them as pests. The combination of current fishing interest and its limited range have contributed to its current status, though there is no evidence that their numbers have declined. The South African Sea Fisheries Research Institute is considering legally decommercializing the Pyjama shark, which would limit the degree to which it can be targeted by commercial fisheries.
Pyjama Shark or Striped Catshark Recorded Attacks on Humans: Not a threat to humans. It is hard to approach underwater.