Tiger catshark
Encyclopedia
The tiger catshark is a species
of catshark
, family
Scyliorhinidae. 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 (328.1 ft). Reaching a length of 50 cm (19.7 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.
Bottom-dwelling and inactive, the tiger catshark feeds on a wide variety of fish
es and invertebrate
s from on or near the sea floor. An oviparous species, the female retains her eggs internally until the embryo
s 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 Data Deficient
by the International Union for Conservation of Nature (IUCN), pending more information.
by J. F. Queckett. He placed the species in the genus
Scyllium (a synonym
of Scyliorhinus
) and gave it the specific epithet , 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
). Later authors reassigned this species to the genus Halaelurus
. The lined catshark
(Halaelurus lineatus) was once treated as conspecific to the tiger catshark, until it was described as a separate species in 1975.
, 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 reef
s. It is usually found from the shore to a depth of 100 m (328.1 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 (564.3 ft), as well as a single dubious record from 355 m (1,164.7 ft) down on the continental slope. It may segregate by size, with the adults found farther from shore.
s. 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. The teeth are small and 3-cusped (rarely 5-cusped), with the central cusp the longest. The five pairs of gill slit
s are placed higher than the level of the mouth and face somewhat upwards.
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, though those of some individuals may be knob-shaped and spiky. 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. 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.
s. Its diet is dominated by bony fishes and crustacean
s, and also includes cephalopod
s, polychaete worms, smaller sharks, and scavenged
fish offal
. 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. Documented predators of this species include the broadnose sevengill shark
(Notorynchus cepedianus) and the ragged tooth shark (Carcharias taurus).
Reproduction in the tiger catshark is oviparous: females produce 6–11 (typically 6–9) eggs in each of their two oviduct
s at a time. The eggs are contained in tough capsules around 4 cm (1.6 in) long and 1.5 cm (0.590551181102362 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 embryo
s are substantially developed, measuring at least 4.3 cm (1.7 in) long. Thus, the eggs hatch within only 1–2 months of being laid, reducing the amount of time that they are exposed to predators. Males and females begin to reach sexual maturity
at lengths of 29–35 cm (11.4–13.8 in) and 30–44 cm (11.8–17.3 in) respectively.
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 lacks sufficient data to assess its conservation status.
Species
In biology, a species is one of the basic units of biological classification and a taxonomic rank. A species is often defined as a group of organisms capable of interbreeding and producing fertile offspring. While in many cases this definition is adequate, more precise or differing measures are...
of catshark
Catshark
Catsharks are ground sharks of the family Scyliorhinidae, with over 150 known species. While they are generally known as catsharks, many species are commonly called dogfish....
, family
Family (biology)
In biological classification, family is* a taxonomic rank. Other well-known ranks are life, domain, kingdom, phylum, class, order, genus, and species, with family fitting between order and genus. As for the other well-known ranks, there is the option of an immediately lower rank, indicated by the...
Scyliorhinidae. It is found over sandy areas and near reef
Reef
In nautical terminology, a reef is a rock, sandbar, or other feature lying beneath the surface of the water ....
peripheries off South Africa
South Africa
The Republic of South Africa is a country in southern Africa. Located at the southern tip of Africa, it is divided into nine provinces, with of coastline on the Atlantic and Indian oceans...
and perhaps Mozambique
Mozambique
Mozambique, officially the Republic of Mozambique , is a country in southeastern Africa bordered by the Indian Ocean to the east, Tanzania to the north, Malawi and Zambia to the northwest, Zimbabwe to the west and Swaziland and South Africa to the southwest...
, from close to shore to usually no deeper than 100 m (328.1 ft). Reaching a length of 50 cm (19.7 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.
Bottom-dwelling and inactive, the tiger catshark feeds on a wide variety of fish
Fish
Fish are a paraphyletic group of organisms that consist of all gill-bearing aquatic vertebrate animals that lack limbs with digits. Included in this definition are the living hagfish, lampreys, and cartilaginous and bony fish, as well as various extinct related groups...
es and invertebrate
Invertebrate
An invertebrate is an animal without a backbone. The group includes 97% of all animal species – all animals except those in the chordate subphylum Vertebrata .Invertebrates form a paraphyletic group...
s from on or near the sea floor. An oviparous species, the female retains her eggs internally until the embryo
Embryo
An embryo is a multicellular diploid eukaryote in its earliest stage of development, from the time of first cell division until birth, hatching, or germination...
s 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
Bycatch
The term “bycatch” is usually used for fish caught unintentionally in a fishery while intending to catch other fish. It may however also indicate untargeted catch in other forms of animal harvesting or collecting...
by commercial
Commercial fishing
Commercial fishing is the activity of catching fish and other seafood for commercial profit, mostly from wild fisheries. It provides a large quantity of food to many countries around the world, but those who practice it as an industry must often pursue fish far into the ocean under adverse conditions...
and recreational fishers
Recreational fishing
Recreational fishing, also called sport fishing, is fishing for pleasure or competition. It can be contrasted with commercial fishing, which is fishing for profit, or subsistence fishing, which is fishing for survival....
but has no economic value. It has been listed as Data Deficient
Data Deficient
Data Deficient is a category applied by the IUCN, other agencies, and individuals to a species when the available information is not sufficient for a proper assessment of conservation status to be made...
by the International Union for Conservation of Nature (IUCN), pending more information.
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 MuseumBritish Museum
The British Museum is a museum of human history and culture in London. Its collections, which number more than seven million objects, are amongst the largest and most comprehensive in the world and originate from all continents, illustrating and documenting the story of human culture from its...
by J. F. Queckett. He placed the species in the genus
Genus
In biology, a genus is a low-level taxonomic rank used in the biological classification of living and fossil organisms, which is an example of definition by genus and differentia...
Scyllium (a synonym
Synonym (taxonomy)
In scientific nomenclature, a synonym is a scientific name that is or was used for a taxon of organisms that also goes by a different scientific name. For example, Linnaeus was the first to give a scientific name to the Norway spruce, which he called Pinus abies...
of Scyliorhinus
Scyliorhinus
Scylorhinus is a genus of catsharks in the family Scyliorhinidae.-Species:* Scyliorhinus besnardi S. Springer & Sadowsky, 1970 * Scyliorhinus boa Goode & Bean, 1896...
) and gave it the specific epithet , because the type specimens were reportedly collected off the Natal
Natal, South Africa
Natal is a region in South Africa. It stretches between the Indian Ocean in the south and east, the Drakensberg in the west, and the Lebombo Mountains in the north. The main cities are Pietermaritzburg and Durban...
coast of South Africa
South Africa
The Republic of South Africa is a country in southern Africa. Located at the southern tip of Africa, it is divided into nine provinces, with of coastline on the Atlantic and Indian oceans...
(though there is suspicion that they were mislabelled and actually came from Algoa Bay
Algoa Bay
Algoa Bay is a wide inlet along the South African east coast, some 425 miles east of the Cape of Good Hope. It is bounded in the west by Cape Recife and in the east by Cape Padrone. The bay is up to 436 m deep...
). Later authors reassigned this species to the genus Halaelurus
Halaelurus
Halaelurus is a genus of catshark in the family Scyliorhinidae.-Species:* Halaelurus boesemani S. Springer & D'Aubrey, 1972 * Halaelurus buergeri...
. The lined catshark
Lined catshark
The lined catshark or banded catshark is a species of catshark, family Scyliorhinidae, found from Beira, Mozambique to East London, South Africa between latitudes 19° S and 31° S, from the surface to 290 m. Its length is up to 56 cm....
(Halaelurus lineatus) was once treated as conspecific to the tiger catshark, until it was described as a separate species in 1975.
Distribution and habitat
The tiger catshark is endemic to southern AfricaSouthern Africa
Southern Africa is the southernmost region of the African continent, variably defined by geography or geopolitics. Within the region are numerous territories, including the Republic of South Africa ; nowadays, the simpler term South Africa is generally reserved for the country in English.-UN...
, but the limits of its distribution are not well known. It is known to occur off the Western
Western Cape
The Western Cape is a province in the south west of South Africa. The capital is Cape Town. Prior to 1994, the region that now forms the Western Cape was part of the much larger Cape Province...
and Eastern Cape
Eastern Cape
The Eastern Cape is a province of South Africa. Its capital is Bhisho, but its two largest cities are Port Elizabeth and East London. It was formed in 1994 out of the "independent" Xhosa homelands of Transkei and Ciskei, together with the eastern portion of the Cape Province...
, South Africa, while easterly records from KwaZulu-Natal
KwaZulu-Natal
KwaZulu-Natal is a province of South Africa. Prior to 1994, the territory now known as KwaZulu-Natal was made up of the province of Natal and the homeland of KwaZulu....
and Mozambique
Mozambique
Mozambique, officially the Republic of Mozambique , is a country in southeastern Africa bordered by the Indian Ocean to the east, Tanzania to the north, Malawi and Zambia to the northwest, Zimbabwe to the west and Swaziland and South Africa to the southwest...
are uncertain due to confusion with the lined catshark. A common, bottom-dwelling inhabitant of the continental shelf
Continental shelf
The continental shelf is the extended perimeter of each continent and associated coastal plain. Much of the shelf was exposed during glacial periods, but is now submerged under relatively shallow seas and gulfs, and was similarly submerged during other interglacial periods. The continental margin,...
, this shark favours sandy flats and the edges of reef
Reef
In nautical terminology, a reef is a rock, sandbar, or other feature lying beneath the surface of the water ....
s. It is usually found from the shore to a depth of 100 m (328.1 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 (564.3 ft), as well as a single dubious record from 355 m (1,164.7 ft) down on the continental slope. It may segregate by size, with the adults found farther from shore.
Description
The body of the tiger catshark is slim and firm, and it grows up to 50 cm (19.7 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 membraneNictitating membrane
The nictitating membrane is a transparent or translucent third eyelid present in some animals that can be drawn across the eye for protection and to moisten it while maintaining visibility. Some reptiles, birds, and sharks have a full nictitating membrane; in many mammals, there is a small...
s. Beneath each eye is a broad ridge, and behind is a spiracle
Spiracle
Spiracles are openings on the surface of some animals that usually lead to respiratory systems.-Vertebrates:The spiracle is a small hole behind each eye that opens to the mouth in some fishes. In the primitive jawless fish the first gill opening immediately behind the mouth is essentially similar...
. 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. The teeth are small and 3-cusped (rarely 5-cusped), with the central cusp the longest. The five pairs of gill slit
Gill slit
Gill slits are individual openings to gills, i.e., multiple gill arches, which lack a single outer cover. Such gills are characteristic of Cartilaginous fish such as sharks, rays, sawfish, and guitarfish. Most of these have five pairs, but a few species have 6 or 7 pairs...
s are placed higher than the level of the mouth and face somewhat upwards.
The pectoral fins are fairly large and rounded. The origin of the first dorsal fin
Dorsal fin
A dorsal fin is a fin located on the backs of various unrelated marine and freshwater vertebrates, including most fishes, marine mammals , and the ichthyosaurs...
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, though those of some individuals may be knob-shaped and spiky. 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. 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.
Biology and ecology
The tiger catshark is a sluggish predator of a diverse array of benthic organismOrganism
In biology, an organism is any contiguous living system . In at least some form, all organisms are capable of response to stimuli, reproduction, growth and development, and maintenance of homoeostasis as a stable whole.An organism may either be unicellular or, as in the case of humans, comprise...
s. Its diet is dominated by bony fishes and crustacean
Crustacean
Crustaceans form a very large group of arthropods, usually treated as a subphylum, which includes such familiar animals as crabs, lobsters, crayfish, shrimp, krill and barnacles. The 50,000 described species range in size from Stygotantulus stocki at , to the Japanese spider crab with a leg span...
s, and also includes cephalopod
Cephalopod
A cephalopod is any member of the molluscan class Cephalopoda . These exclusively marine animals are characterized by bilateral body symmetry, a prominent head, and a set of arms or tentacles modified from the primitive molluscan foot...
s, polychaete worms, smaller sharks, and scavenged
Scavenger
Scavenging is both a carnivorous and herbivorous feeding behavior in which individual scavengers search out dead animal and dead plant biomass on which to feed. The eating of carrion from the same species is referred to as cannibalism. Scavengers play an important role in the ecosystem by...
fish offal
Offal
Offal , also called, especially in the United States, variety meats or organ meats, refers to the internal organs and entrails of a butchered animal. The word does not refer to a particular list of edible organs, which varies by culture and region, but includes most internal organs other than...
. It has been observed at the spawning grounds of the chokka squid
Loligo vulgaris reynaudi
Loligo reynaudii, commonly known as the Cape Hope Squid, is a large squid belonging to the family Loliginidae. In South Africa it is known as either calamari or chokka....
(Loligo vulgaris reynaudi), feeding on squid that have descended to the bottom to mate and deposit eggs. Documented predators of this species include the broadnose sevengill shark
Broadnose sevengill shark
The broadnose sevengill shark is the only extant member of the genus Notorynchus, in the family Hexanchidae. It is recognizable because of its seven gill slits, while most shark species have five gill slits, with the exception of the members of the order Hexanchiformes and the sixgill sawshark.The...
(Notorynchus cepedianus) and the ragged tooth shark (Carcharias taurus).
Reproduction in the tiger catshark is oviparous: females produce 6–11 (typically 6–9) eggs in each of their two oviduct
Oviduct
In non-mammalian vertebrates, the passageway from the ovaries to the outside of the body is known as the oviduct. The eggs travel along the oviduct. These eggs will either be fertilized by sperm to become a zygote, or will degenerate in the body...
s at a time. The eggs are contained in tough capsules around 4 cm (1.6 in) long and 1.5 cm (0.590551181102362 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 embryo
Embryo
An embryo is a multicellular diploid eukaryote in its earliest stage of development, from the time of first cell division until birth, hatching, or germination...
s are substantially developed, measuring at least 4.3 cm (1.7 in) long. Thus, the eggs hatch within only 1–2 months of being laid, reducing the amount of time that they are exposed to predators. Males and females begin to reach sexual maturity
Sexual maturity
Sexual maturity is the age or stage when an organism can reproduce. It is sometimes considered synonymous with adulthood, though the two are distinct...
at lengths of 29–35 cm (11.4–13.8 in) and 30–44 cm (11.8–17.3 in) respectively.
Human interactions
Harmless to humans, the tiger catshark is caught incidentallyBycatch
The term “bycatch” is usually used for fish caught unintentionally in a fishery while intending to catch other fish. It may however also indicate untargeted catch in other forms of animal harvesting or collecting...
by bottom trawlers, recreational
Recreational fishing
Recreational fishing, also called sport fishing, is fishing for pleasure or competition. It can be contrasted with commercial fishing, which is fishing for profit, or subsistence fishing, which is fishing for survival....
anglers
Angling
Angling is a method of fishing by means of an "angle" . The hook is usually attached to a fishing line and the line is often attached to a fishing rod. Fishing rods are usually fitted with a fishing reel that functions as a mechanism for storing, retrieving and paying out the line. The hook itself...
, 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 lacks sufficient data to assess its conservation status.