The Striped Shark, also known as the Pyjama Shark (Poroderma africanum) is a type of catshark that belongs to the family of Scyliorhinidae and is native to the coastal waters of South Africa. Read on to find out more about the biology, habitat and vast description of the Striped Shark.
Striped Shark – Description
The Striped Shark, also known as the Pyjama Shark (for their striped pattern) is an abundant species that lives in tidal zones at depths of up to 100 m in rocky reefs and kelp beds. With a series of thick parallel dark stripes running across his stocky body, they have a very distinctive appearance.
The Striped Shark can grow up to 1.1 m long. It is characterized by a short head and a short snout, a pair of short slender barbels that do not reach the mouth and two dorsal fins close to the body. It is nocturnal and spends most of the day motionless in caves and crevices in the vegetation.
It is an opportunistic predator that feeds on a variety of fish and invertebrates, although it prefers cephalopods and visits spawning grounds for chokka squid (Loligo reynaudi). When threatened, it will curl up into a circle with its tail covering its head.
The pyjama shark has the largest and thickest body of the two Poroderma species and weighs from 79kg or more. Both sexes grow up to the same maximum size. Head and muzzle are short and flattened, viewed from above they have a parabolic outline.
The mouth forms a broad arch with a short furrow that extends from the corner of the upper jaw to the lower jaw and exposes the upper teeth when the mouth is closed. The nostrils are divided into tiny, incurable and exact openings, and in the front there is a skin flap; this flap is three-lobed, the middle flap forming a long conical barb. The barbel is thicker than that of leopard sharks and cat sharks, but does not reach the mouth. The eyes are oval and placed close to the head, with a rudimentary nicking membrane and a protective third eyelid with a thick ridge running over it.
The teeth are slender, with a central tip, flanked by a pair of small canines, and adult males have thicker teeth than females. The teeth are in rows of 18–25 and 14–24 on either side of the jaws, both upper and lower sides. The body is compressed from side to side and tapers to the tail. Two dorsal fins are present, the first comes from the back of the pelvic fin and the second from the middle of the anal fin.
The body is quite compressed from side to side and tapers towards the tail. The two dorsal fins are placed far back: the first arises over the back of the pelvic fins, while the second arises over the middle of the anal fin. The first is much larger than the second. The pectoral fins are large and broad. The pelvic fins are lower than the pectoral fins, but their bases are approximately the same length.
Adult males have a pair of short, thick claspers on which the inner edges of the pelvic fins partially fuse to form an ‘apron’. The short, broad caudal fin has an indistinct lower lobe and a ventral notch near the end of the higher lobe. The skin is very thick and has well calcified dermal teeth. Each denticle has an arrowhead shaped crown with three posterior points mounted on a short stem.
The dorsal coloration is distinctive and consists of 5-7 dark, parallel and thick stripes that go from the snout to the caudal peduncle, on a grey or brownish background; the strips break near the tail and abdomen. In some sharks, the main stripe may be forked on either side behind the eye, the stripes may be divided in two by lighter central lines, or there may be one or more large dark spots.
The underside is pale, sometimes with light grey spots and clearly demarcated by the color of the flank. Young sharks are similar to adults, but they can be much lighter or have much darker stripes.
Striped Shark Interactions With Humans
Among the most common South African cat sharks, the Striped Shark is harmless to humans and difficult to approach underwater. Due to its small size, attractive appearance and strength, it is commonly displayed in public aquariums. The aquarium trade supports small-scale fishing aimed at this species and the similar leopard catshark.
Commercial fishing accidentally catches large numbers of Striped Sharks with longlines, gillnets and bottom trawls. They are also easily hooked by recreational fishermen, especially during the summer when they are added. Although edible, most are discarded, while some are used as lobster bait. The number of casualties from bycatch fishing is likely greatly underestimated, as many line fishermen view Striped Sharks as parasites that ‘steal’ the bait and kill them before discarding them.
Reproduction
The reproduction takes place oviparously, with the female laying rectangular, dark brown eggs twice per year.
The Striped Shark gives birth to rectangular shaped eggs, with the females producing two eggs each. When a young hatches, it is about 14-15cm long. The female Striped Shark can grow up to 101cm long. Male Striped Sharks, especially adolescents, are 78-81cm long, while adult males are 75-91cm long. Female Striped Sharks, especially juveniles, can be 79-83cm long, while adults can be 75-93cm long.
Conservation
These small, harmless sharks are often caught as by-catch in both commercial and recreational fisheries. Many are killed by fishermen who regard them as pests. The data indicates that their numbers are not declining, and the International Union for Conservation of Nature (IUCN) rates them as the least worrying in terms of conservation. They adapt well to captivity and are often exhibited in public aquariums.
Striped Shark – Geographical Location & Habitat
The Striped Shark is an inhabitant of the seabed in temperate coastal waters, and is found off South Africa, from Table Bay off Cape Town to the north of East London. It is most abundant in the Western Cape and can reach as far as Saldanha Bay in the west and eastern KwaZulu-Natal.
The Striped Shark is commonly found in very shallow coastal and intertidal waters at no more than 5m (16 ft) deep, although in and around Algoa Bay it is found at depths of 50 to 100m (160 to 330 feet) and has been reported to be as roaming as deep as 108m (35 ft). It prefers rocky cliffs and Ecklonia seaweed beds (kelp).