Tiger catshark

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Tiger catshark
Halaelurus natalensis fb.jpg
Scientific classification OOjs UI icon edit-ltr.svg
Domain: Eukaryota
Kingdom: Animalia
Phylum: Chordata
Class: Chondrichthyes
Subclass: Elasmobranchii
Order: Carcharhiniformes
Family: Pentanchidae
Genus: Halaelurus
Species:
H. natalensis
Binomial name
Halaelurus natalensis
(Regan, 1904)
Halaelurus natalensis distmap.png
Range of the tiger catshark [2]
Synonyms

Scyllium natalenseRegan, 1904

The tiger catshark (Halaelurus natalensis) is a species of shark belonging to the family Pentanchidae, the deepwater catsharks. It is found over sandy areas and near reef peripheries off South Africa and perhaps Mozambique, from close to shore to usually no deeper than 100 m (330 ft). Reaching a length of 50 cm (20 in), this small, slim shark has a broad, flattened head with an upturned snout tip. It can additionally be identified by its dorsal colour pattern of ten dark brown saddles on a yellowish brown background.

Contents

Bottom-dwelling and inactive, the tiger catshark feeds on a wide variety of fishes and invertebrates from on or near the sea floor. An oviparous species, the female retains her eggs internally until the embryos are at an advanced state of development, resulting in a relatively short hatching time after laying. Between 12 and 22 encapsulated eggs are produced at a time, which the female attaches to the bottom. The tiger catshark is caught incidentally by commercial and recreational fishers but has no economic value. It has been listed as vulnerable by the International Union for Conservation of Nature (IUCN).

Taxonomy

British ichthyologist Charles Tate Regan described the tiger catshark in a 1904 issue of the scientific journal Annals and Magazine of Natural History , based on two specimens presented to the British Museum by J. F. Queckett. He placed the species in the genus Scyllium (a synonym of Scyliorhinus ) and gave it the specific epithet natalense, because the type specimens were reportedly collected off the Natal coast of South Africa (though there is suspicion that they were mislabelled and actually came from Algoa Bay). [3] [4] Later authors reassigned this species to the genus Halaelurus . [5] The lined catshark (Halaelurus lineatus) was once treated as conspecific to the tiger catshark, until it was described as a separate species in 1975. [6]

Description

The body of the tiger catshark is slim and firm, and it grows up to 50 cm (20 in) long. The head is broad and flattened, with a distinct and upturned snout tip. The horizontally oval eyes are situated high on the head and protected by rudimentary nictitating membranes. Beneath each eye is a broad ridge, and behind is a spiracle. The medium-sized nostrils are divided by lobe-like flaps of skin on their anterior rims. The nasal flaps do not reach the large mouth, which forms a wide arch and bears short furrows around the corners. When the mouth is closed, the centre of the lower jaw falls well short of the upper, leaving the upper teeth exposed. [5] The teeth are small and 3-cusped (rarely 5-cusped), with the central cusp the longest. [6] The five pairs of gill slits are placed higher than the level of the mouth and face somewhat upwards. [5]

The pectoral fins are fairly large and rounded. The origin of the first dorsal fin lies over the last third of the pelvic fin bases, while the origin of the much larger second dorsal fin lies over the rear of the anal fin. The claspers of adult males are moderately long and tapering, [5] though those of some individuals may be knob-shaped and spiky. [4] The anal fin is roughly equal in size to the pelvic fins, and smaller but longer-based than the second dorsal fin. The short caudal fin has an indistinct lower lobe and a ventral notch near the tip of the upper lobe. The skin is thick; the dermal denticles have three-pointed crowns and are widely spaced compared to other species in the genus. [5] [6] Coloured yellowish brown above and cream below, this shark has a characteristic series of ten dorsal saddles from the head to the tail; each saddle is dark brown with a darker edge and a lighter middle. Unlike in the similar lined catshark, there are no spots or additional markings between the saddles. [2] [4]

Distribution and habitat

The tiger catshark is endemic to southern Africa, but the limits of its distribution are not well known. It is known to occur off the Western and Eastern Cape, South Africa, while easterly records from KwaZulu-Natal and Mozambique are uncertain due to confusion with the lined catshark. A common, bottom-dwelling inhabitant of the continental shelf, this shark favours sandy flats and the edges of reefs. It is usually found from the shore to a depth of 100 m (330 ft); sharks in the eastern part of its range tend to occur in deeper water than those in the west. There are species records from as deep as 172 m (564 ft), [1] as well as a single dubious record from 355 m (1,165 ft) down on the continental slope. It may segregate by size, with the adults found farther from shore. [2] [4]

Biology and ecology

The broadnose sevengill shark is known to prey on the tiger catshark. Notorynchus cepedianus false bay3.jpg
The broadnose sevengill shark is known to prey on the tiger catshark.

The tiger catshark is a sluggish predator of a diverse array of benthic organisms. [4] Its diet is dominated by bony fishes and crustaceans, and also includes cephalopods, polychaete worms, smaller sharks, and scavenged fish offal. [1] [2] It has been observed at the spawning grounds of the chokka squid (Loligo vulgaris reynaudi), feeding on squid that have descended to the bottom to mate and deposit eggs. [7] Documented predators of this species include the broadnose sevengill shark (Notorynchus cepedianus) and the ragged tooth shark (Carcharias taurus). [8] [9]

Reproduction in the tiger catshark is oviparous: females produce 6–11 (typically 6–9) eggs in each of their two oviducts at a time. [1] The eggs are contained in tough capsules around 4 cm (1.6 in) long and 1.5 cm (0.59 in) across; the capsule has thick tendrils at the corners that allow it to be secured to the sea floor. The female retains the eggs internally until the embryos are substantially developed, measuring at least 4.3 cm (1.7 in) long. Thus, the eggs hatch within only one or two months of being laid, reducing the amount of time that they are exposed to predators. [4] [5] Males and females begin to reach sexual maturity at lengths of 29–35 cm (11–14 in) and 30–44 cm (12–17 in) respectively. [2]

Human interactions

Harmless to humans, [10] the tiger catshark is caught incidentally by bottom trawlers, recreational anglers, and rarely squid fishers. Though edible, it is not a valued catch and is usually discarded. The International Union for Conservation of Nature (IUCN) presently classifies this species as vulnerable. [1] [4]

Related Research Articles

<span class="mw-page-title-main">Broadnose sevengill shark</span> Species of shark

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<span class="mw-page-title-main">Sand tiger shark</span> Species of shark

The sand tiger shark, grey/gray nurse shark, spotted ragged-tooth shark or blue-nurse sand tiger, is a species of shark that inhabits subtropical and temperate waters worldwide. It inhabits the continental shelf, from sandy shorelines and submerged reefs to a depth of around 191 m (627 ft). They dwell in the waters of Japan, Australia, South Africa, and the east coasts of North and South America. The sand tiger shark also inhabited the Mediterranean, however it was last seen there in 2003 and is presumed extinct in the region. Despite its common names, it is not closely related to either the tiger shark or the nurse shark.

<span class="mw-page-title-main">Australian swellshark</span> Species of shark

The Australian swellshark or draughtboard shark, is a species of catshark, and part of the family Scyliorhinidae, endemic to southern Australia. This bottom-dwelling species can be found on the continental shelf down to a depth of 220 m (720 ft). Usually measuring 1 m long, it is a stout-bodied, broad-headed shark with a short tail and a first dorsal fin much larger than the second. It can be identified by its variegated dorsal coloration of brown or grey patches and numerous spots.

<span class="mw-page-title-main">Balloon shark</span> Species of shark

The balloon shark is a species of catshark, and part of the family Scyliorhinidae, endemic to the southwestern Indian Ocean off South Africa and Mozambique. Benthic in nature, it is found over sandy and muddy flats at depths of 40–600 m (130–1,970 ft). This thick-bodied species has a broad, flattened head and a short tail; its distinguishing traits include narrow, lobe-like skin flaps in front of the nostrils, and a dorsal color pattern of faint darker saddles on a light grayish background.

<span class="mw-page-title-main">Blotchy swellshark</span> Species of shark

The blotchy swellshark or Japanese swellshark is a common species of catshark, belonging to the family Scyliorhinidae. The Blotchy swellshark is found at depths of 90–200 m (300–660 ft) in the northwestern Pacific Ocean, from Japan to Taiwan. It is benthic in nature and favors rocky reefs. Reaching 1.4 m (4.6 ft) in length, this thick-bodied shark has a broad head, large mouth, and two unequally-sized dorsal fins positioned far back past the pelvic fins. It can be identified by its dorsal coloration, consisting of seven brown "saddles" and extensive darker mottling on a light tan background. This species has often been confounded with the draughtsboard shark and the Sarawak pygmy swellshark in scientific literature.

<span class="mw-page-title-main">Pyjama shark</span> Species of shark

The pyjama shark or striped catshark is a species of catshark, and part of the family Scyliorhinidae, endemic to the coastal waters of South Africa. This abundant, bottom-dwelling species can be found from the intertidal zone to a depth of around 100 m (330 ft), particularly over rocky reefs and kelp beds. With a series of thick, parallel, dark stripes running along its stout body, the pyjama shark has an unmistakable appearance. It is additionally characterized by a short head and snout with a pair of slender barbels that do not reach the mouth, and two dorsal fins that are placed far back on the body. It can grow up to a length of 1.1 m (3.6 ft) long.

<span class="mw-page-title-main">Leopard catshark</span> Species of shark

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<span class="mw-page-title-main">Izak catshark</span> Species of catshark, of the family Scyliorhinidae

The Izak catshark or simply Izak is a species of shark belonging to the family Pentanchidae, the deepwater catsharks. This species is common off the coasts of South Africa and southern Namibia. It typically inhabits the outer continental shelf at depths of 100–300 m (330–980 ft), with the males found deeper than the females and juveniles. The Izak catshark has a short, wide, flattened head and a robust body tapering to a long, slender tail. It can be identified by its ornate color pattern of dark brown spots or reticulations and blotches on a light yellowish background, as well as by the enlarged dermal denticles over its pectoral fins and along its dorsal midline from the snout to the second dorsal fin. This species reaches 69 cm (27 in) in length, with the males larger than females.

<i>Haploblepharus</i> Genus of sharks

Haploblepharus is a genus of deepwater catsharks, belonging to the family Pentanchidae, containing four species of shysharks. Their common name comes from a distinctive defensive behavior in which the shark curls into a circle and covers its eyes with its tail. The genus is endemic to southern Africa, inhabiting shallow coastal waters. All four species are small, stout-bodied sharks with broad, flattened heads and rounded snouts. They are characterized by very large nostrils with enlarged, triangular flaps of skin that reach the mouth, and deep grooves between the nostrils and the mouth. Shysharks are bottom-dwelling predators of bony fishes and invertebrates. They are oviparous, with the females laying egg capsules. These harmless sharks are of no commercial or recreational interest, though their highly limited distributions in heavily fished South African waters are of potential conservation concern.

<span class="mw-page-title-main">Sharptooth houndshark</span> Species of shark

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<span class="mw-page-title-main">Puffadder shyshark</span> Species of shark

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<span class="mw-page-title-main">Dark shyshark</span> Species of shark

The dark shyshark or pretty happy is a species of shark belonging to the family Pentanchidae, the deepwater catsharks. This species is endemic to the temperate waters off southern Namibia and western South Africa. It is benthic in nature and inhabits shallow, inshore waters and favors rocky reefs and kelp forests. Growing to 60 cm (24 in) long, this small, stocky shark has a wide, flattened head with a rounded snout and a large flap of skin extending from before the nostrils to the mouth. Its dorsal coloration is extremely variable and may feature black-edged orange to blackish saddles and/or white spots on a light brown to nearly black background.

<span class="mw-page-title-main">Quagga catshark</span> Species of fish

The quagga catshark is a species of shark belonging to the family Pentanchidae, the deepwater catsharks. A small, slim-bodied shark reaching 37 cm (15 in) in length, it has a distinctive color pattern of narrow, dark brown vertical bars, which resemble those of the quagga. Its head is short and flattened, with a pointed snout tip that is not upturned.

<span class="mw-page-title-main">Blackspotted catshark</span> Species of shark

The blackspotted catshark is a species of shark belonging to the family Pentanchidae, the deepwater catsharks. It is found in the waters off the coasts of Japan, Korea, China, and Taiwan between latitudes 39° N and 20° N, at the depths of between 80 and 100 m. It can grow up to 49 cm in length.

<span class="mw-page-title-main">Speckled catshark</span> Species of shark

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<span class="mw-page-title-main">Australian sawtail catshark</span> Species of shark

The Australian sawtail catshark is a common species of deepwater catshark, belonging to the family Pentanchidae, endemic to southern Australian waters. It is found on or near the bottom of the outer continental shelf and upper continental slope, at depths of 85 to 823 m. This slim-bodied species is characterized by crests of enlarged dermal denticles along both the dorsal and ventral edges of its caudal fin and caudal peduncle, along with a color pattern of broad, dark saddles outlined in white. It can grow to 61 cm (24 in) in length. The Australian sawtail catshark feeds mainly on fishes, crustaceans, and cephalopods. Females are oviparous and lay eggs enclosed by capsules. This species is often caught incidentally by commercial bottom trawl fisheries, but is not significantly threatened by fishing activity. Thus, it has been assessed as of Least Concern by the International Union for Conservation of Nature (IUCN).

<span class="mw-page-title-main">Gecko catshark</span> Species of shark

The gecko catshark is a species of deepwater catshark, belonging to the family Pentanchidae, native to the northwestern Pacific Ocean from southern Japan to Taiwan, and possibly also off Vietnam. It is a common, demersal species found at depths of 100–900 m (330–2,950 ft). Its body is slender, with a pattern of dark saddles and blotches. The dorsal and caudal fins are edged in white, and there is a prominent crest of enlarged dermal denticles along the dorsal edge of the caudal fin. The gecko catshark is a schooling, opportunistic predator of bony fishes, cephalopods, and crustaceans. It is oviparous, with females producing two vase-shaped egg capsules at a time. This species is captured as bycatch, but does not appear to be threatened by fishery activities at present and has been assessed as Least Concern by the International Union for Conservation of Nature (IUCN).

<span class="mw-page-title-main">Mouse catshark</span> Species of shark

The mouse catshark is a species of shark belonging to the family Pentanchidae, the deepwater catsharks. It is common in the northeastern Atlantic Ocean from Iceland to Western Sahara. There is much taxonomic confusion regarding this species in Icelandic waters, where it may be confounded with another species of Galeus or Apristurus. Probably not exceeding 49 cm (19 in) long, the mouse catshark has a uniformly brown body and is characterized by large, rounded pelvic fins and crests of enlarged dermal denticles along both the dorsal and ventral caudal fin margins. In addition, in adult males the inner margins of the pelvic fins are merged into an "apron".

<span class="mw-page-title-main">Broadfin sawtail catshark</span> Species of shark

The broadfin sawtail catshark is a species of shark belonging to the family Pentanchidae, the deepwater catsharks. It is found on or near the bottom at depths of 150–540 m (490–1,770 ft), from southeastern Japan to the East China Sea. A slender species growing to 68 cm (27 in) long, this shark is characterized by a fairly long, pointed snout, a series of indistinct, dark saddles along its back and tail, and a prominent crest of enlarged dermal denticles along the dorsal edge of its caudal fin. In addition, adult males have very long claspers that reach past the anal fin. The broadfin sawtail catshark is an opportunistic predator of bony fishes, cephalopods, and crustaceans, with immature and mature sharks being primarily piscivorous. It is oviparous and reproduces year-round.

<span class="mw-page-title-main">African sawtail catshark</span> Species of shark

The African sawtail catshark is a species of shark belonging to the family Pentanchidae, the deepwater catsharks. Demersal in nature, it is found at depths of 160–720 m (520–2,360 ft) off the western African coast from Morocco to South Africa. This slender species has a rather long, pointed snout, a series of dark saddles along the back and tail, and a prominent crest of enlarged dermal denticles along the upper edge of the caudal fin. Its maximum known length is 46 cm (18 in).

References

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  7. Sauer, W. H. H.; Smale, M. J. (December 1991). "Predation patterns on the inshore spawning grounds of the squid Loligo vulgaris reynaudii (Cephalopoda: Loliginidae) off the south-eastern Cape, South Africa". South African Journal of Marine Science. 11 (1): 513–523. doi: 10.2989/025776191784287736 .
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  9. Smale, M. J. (January 2005). "The diet of the ragged-tooth shark Carcharias taurus Rafinesque 1810 in the Eastern Cape, South Africa" (PDF). African Journal of Marine Science. 27 (1): 331–336. doi:10.2989/18142320509504091. S2CID   84782633. Archived from the original (PDF) on 2012-04-02.
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