The Sand Tiger Shark (Carcharias Taurus)

The Sand Tiger Shark (Carcharias Taurus)

Large, bulky shark with flat conical snout, eyes with nicking eyelids, mouth extending from eye to teeth, large, conspicuously narrow canines, lateral canines, upper incisors separated by lateral teeth, small interstitial teeth, anal fin, dorsal fin large at the base of the first dorsal fin, pelvic fin, pectoral fin, upper prevention pit present, caudal stem and tail asymmetric.

Names

  • English: Sand tiger shark
  • French: Requin taureau
  • Spanish: Toro bacota
The Sand Tiger Shark (Carcharias Taurus)
The Sand Tiger Shark (Carcharias Taurus)

Distribution Of The Sand Tiger Shark

The distribution ranges from warm temperate to tropical coastal waters of the Atlantic, Mediterranean and Indo-West Pacific oceans, but is absent in the Central Pacific and Eastern Pacific.

Cape Verde Islands, Morocco, Western Sahara, Mauritania, Sao Tome and Principe,: Canary Islands, Senegal, Ghana, Southern Nigeria, Cameroon, Angola, Namibia, South Africa, Western Cape. Gulf of Maine and New Brunswick (rare), US: Cape Cod, Massachusetts, New York, Rhode Island, Connecticut, New Jersey, Delaware, Maryland, Virginia, North Carolina, South Carolina, Florida, Northern Gulf of Mexico (including West Florida, Louisiana, Texas, Bahamas, Bermuda), southern Brazil, Uruguay and Argentina. Lndonesia, Laiwui, Obi Major, Aru Islands, Malaysia, Vietnam, Philippines, Japan, Taiwan Province, China (China), Australia: Queensland, New South Wales, Victoria, South Australia, Northern Territory, Western Australia, Tasmania (records subject to confirmation). South Africa (central East Coast), Mozambique, Providence, Farquhar and the Cerf Islands, the Western Indian Ocean, the Red Sea, Oman, Pakistan and Lndia.

Colour Of The Sand Tiger Shark

Light brown to dark reddish-brownish with spots all over the body and around the eyes, with light green irises.

Habitat Of The Sand Tiger Shark

Coastal, coastal and coastal sharks. These sharks are found in surfing zones, sandy and rocky beaches, shallow bays, offshore shores, reefs, underwater caves, troughs, sandy areas, coral and rock reefs, tidal reefs (less than 1 m (1.91 m)) and offshore reefs, at most depths from 1.5 to 2.5 m. They occur near the bottom, but can also occur in the middle of the water and near the surface. Frequent, frequent and abundant, they occur in large aggregates and in breeding.

Biology Of The Sand Tiger Shark

The Sand Tiger Shark is a strong but slow medium-water swimmer and is most active at night. When it is in dense water, it swallows air from the surface and holds it in its stomach for neutral buoyancy. Like a bony fish with a floating bladder, it stops and floats motionless in the water and in the stable.

The species occurs as a loner or in small to large groups (schools) of 20 to 80 individuals in Australia and South Africa. Collections of individuals occur during feeding, courtship, mating and birth. The species migrates in all parts of its range from its northern to its southern extremes, with the most obvious polar migration in summer and equatorial migrations in Autumn and winter in Australia, off the east coast of the United States and off the east coast of South Africa.

Before South Africa, it comes to courtship display and combination in the tropical parts of the spread-area, and pregnant females bear in warm-restrained waters. In Australia, sexual segregation (segregated migration of the sexes) occurs along the east coast of Australia, with males predominating in southern Queensland and wintering females in New South Wales. In North America, the breeding areas are not exactly defined, but the species gives birth to its entire range in March and April.

Gordon (1993) has studied the behaviour of sharks in captivity in a large shark tank where sand tigers, young adults of wobbegongs (Orectolobus), grey sharks (Carcharhinus sevengills) and Notorynchus rays live on a reef in the pelagic teleeast. The study showed evidence of complex behavior, including social interactions, courtship and mending between the three adult sharks as well as antisocial interactions with other marine vertebrates and divers. Dominance hierarchies were recorded for all three species.

Two adult males became hesitant and aggressive towards other fish, particularly grey sharks. Most of this behaviour was observed during courtship and mating. Adult female slowed down and had a large shallow sand cup on her pelvic fin. As one male approached the two adult males, the color shifted and began to defend the shallow sand area, grabbing the stalks and tails of immature sand tigers and other sharks and divers. The snapping and tailing resulted in one male expelling the other and scarring it.

A few days after the courtship between the dominant male and the female, the male grabbed the right flank of the female with the pectoral fin and curled its body until the female inserted her right clamp into her cloaca and showed little interest after a few minutes break. The male then bit the female into the anal fin and pectoral fin, and she bit back, and the male returned to patrol the sandy area. The shielding took place with a flare of the female pelvic fin, to which the male reacted with a nose. Additional scars on the female indicated that in at least one case a secondary mating had taken place.

The reproduction of this species, like most other lamnoids, is known for uterine cannibalism (cannibal viviparia). Gilmore, Dodrill and Linley (1983) provide a detailed and fascinating account of this process, documenting a sequence of intrauterine feeding in which successful embryos of the species progress from the use of stored yolks to kill and consume other embryos to the consumption of unfertilized eggs during 9-12 months of gestation. At the time of fertilization and birth, an embryo prevails in its group and eats its rival, and then eats the fertilized eggs of smaller potential siblings in the womb and at birth. The eggs leave the ovary on their way through the egg canal and fertilise in closed groups of 16 to 23 eggs. Two cubs are litters in a uterus.

Both species breed together the rest of the year and twice a year during the entire pregnancy. In egg-shaped (non-cannibal) and viviparous species, the yolk sac is absorbed again and the small size (less than 17 cm) of the umbilical scar is lost. The 17 cm tall foetus has sharp, functional teeth and feeds on 26 cm tall foetuses swimming around in the uterus, while the deceased foetus (1 m long) is the one that bit the hand, as scientist Stewart Springer has studied.

t is thought that the species casts two growth rings on its vertebrae each year, with males growing up at the age of five and females at the age of six. Growth is rapid in the first five years, decreases after 10 years and ceases after 16 years. Growth rings suggest the animal can live to 10 years, and one adult male survived 17 years in captivity in South Africa.

The predators of the elasmobranches are Requiem sharks (Carcharhinidae), cocksharks (Triakidae), Angel sharks (Squatinidae), skates (Rajidae) and Skate eggs and in some cases eagle rays (Myliobatis and Myliobatidae). Invertebrates include cuttlefish (Loliginidae), crabs, lobsters and hermit crabs (Paguridae). The sand tiger feeds on a variety of bony fish, teleosts, and elastomer brains, but the most important secondary prey are crustaceans, cephalopods, and marine mammals, which are also caught. In Uruguay, Praderi (1985) found the remains of 7 individuals (12 of whom were identified as sea lions, Otaria 2 and 557) in the stomach of a sand tiger with wounds attributed to the shark, while two Franciscana dolphins (Pontoporia and Blainvillei) were not among predators. No plant material was found in the stomach contents of the captured animal prey.

Australian and South African sharks have hydroid growths on their teeth, suggesting they don’t feed all the time. It has been observed that swarm sharks feed by surrounding and feeding on a group of swarm marsupials, using tail strokes to scare or confuse the swarm marsupials.

Size Of Sand Tiger Shark

The maximum total length is 318 cm, although recent records of shark mesh operations in Australia indicate a maximum of 4.3 m. Some older reports attribute a size of 6.1 m to the species back in 1878, but this is unlikely. Males grow to 190-195 cm as adults (220-257 cm), females to 220 cm or more and reach 300 cm and immature to 225 cm.

Human Impact On Sand Tiger Sharks

The shark is of only moderate importance for commercial fisheries compared to the more common carcharhinids. Caught on lines or fishing gears attached to the bottom in gold nets or pelagic bottom trawls. Interest in fishing and the impact of fluman on the shark and the fish it finds in the western North Pacific where it is a sought-after food, in tropical West Africa and the northern Indian Ocean off India and Pakistan and in the West Atlantic, where it is less valuable than Atlantic fish due to its skin and fins.

The meat of sharks used for human consumption is used fresh, frozen, smoked, dried or salted, fishmeal, hides, leather, skin, thick, chewy hides, spoiled companions, scarred livers, oiled fins and oriental shark fins traded for jaws, teeth and trophy ornaments. In Australia and New South Wales, meat has been found to contain high levels of mercury, up to ten times higher than the maximum allowable level, making the shark unfit for human consumption. Sand tigers are sought by anglers because of their size for the fishing competition, especially in South Africa, where they are sluggish on the hook and rarely fight.

Australian anglers agreed to a ban on sand tiger sharks in 1979. Divers used poison spears to find the slow-moving species as an easy target in Australia and, to a limited extent, in South Africa. Such a crude and barbaric sport, analogous to shooting domestic cattle with a gun, caused a sharp decline in species numbers in Australia and was banned in 1984. South African divers stopped shooting groupers many years ago.

The sharks have a poor reputation as maneaters in Australian waters and shark attacks are often exaggerated, but this could be due to confusion with other species such as the Requiem shark (Carcharhinidae) and the Great White shark. Separate catch statistics for the sand tiger shark are not reported to the FAO. Sharks are often caught in the public aquarium trade, but the number of sharks involved in this trade is not recorded and can be very small.

Observations of this underwater shark suggest that it is harmless and not aggressive towards people who do not provoke it, and that its size and jagged teeth demand respect. It steals fish sticks and spears underwater, underscoring the usefulness of boats in which to catch them from others. There are few valid cases of it biting people, and reports of minimalist bites by divers in South Africa suggest non-predatory behaviour rather than agonistic activity, similar to scar bites given to divers in aquariums by conspecifics of other shark species. It harasses and bites divers when they take legal action against adults.

Divers can observe accumulations of this shark in Australia, New South Wales, South Africa and offshore North America’s east coast. Regular charter tours include places with frequent shark communities.

Interest in ecotourism diving by sand tiger sharks is high in Australia which leads to potential problems, such as too many divers chasing sharks out of a particular area or overfeeding them, which can lead to possible bite incidents. For the future of the great white shark a management of the dive contact with the sand tiger shark is necessary. In South Africa, tiger sharks have been caught, tagged and released alive by recreational anglers and scientists, and in Australia a sonic tagging is planned to track movements.

The sharks are popular exhibits in large aquariums (Oceanaria) in the United States, Europe, Australia and South Africa. They are hardy and docile in captivity, grow up and live for decades in aquariums that are held with other sharks and fish, where they prey on fish, bite and kill other sharks, impressively displaying their striking, tame, shark-like appearance, size and ability to approach and feed underwater divers. The Aquarium in Cape Town, South Africa, allows ecotourist divers to swim with the sharks in their huge oceanic pools. Adults court and give birth in appropriate tanks.

This species is of concern due to its vulnerability to fisheries and its decline in eastern North America and Australia. It is listed as an endangered species by the IUCN on its Red List of Endangered Species. The species gathers in large numbers during the breeding season in coastal areas accessible to commercial fishermen who can catch them with little effort.

In New South Wales, Australia, it began to decline in the 1960s, when fisheries, including those caught by recreational divers and in anti-shark nets, declined thirty-fold. As Smith (AU) showed in 1998, it has a medium-sized intrinsic recovery potential, but since the creation of a new stimulus plan by the Australian government (Environment Australia, 2000a) it has shown no signs of recovery. New South Australia since 1984, Queensland and Commonwealth waters in Australia and federal waters off the east coast of the USA. A burgeoning Sand Tiger Fishery in the 1990s off the East Coast of America led to a decline in local catches, and in North Carolina, Florida and the Chesapeake Bay was given full protection from recreational and commercial fishing in 1997.

The South African Sea Fisheries Research Institute for Marine and Coastal Management is currently considering a proposal to decompose the species so it can be fished by recreational anglers. Little is known about trends in other places where the Sand Tiger is flung, including the Western North Pacific, the Western South Atlantic and the eastern North Atlantic.

Research

Dental labels were used to distinguish different species (see Bigelow and Schroeder 1948) from different samples from a particular region (Applegate 1965; Sadowsky 1970; Taniuchi 1970). Notes include the synonym Carcharia taurus, but a number of regional species that are considered valid in older literature are probably local representatives of local subspecies and not just a single distribution.

Odontaspisplatensis in the Western South Atlantic, Carcharias tricuspidatus in the Horn of the Indian Subcontinent, C. owstoni in the West Pacific and C. arenariushom in Australia. Carcharia taurus itself was divided into different genera: Odontaspi taurus, Eugomphodus taurus and Synodontaspier taurus.

Literature

  • 1810: Rafinesque
  • 1878: Day
  • 1913: Garman
  • 1940: Whitley
  • 1948: Bigelow and Schroeder
  • 1948: Springer
  • 1956: Cadenat
  • 1964: D’Aubrey
  • 1965: Applegate
  • 1968,1969: Abe et al.
  • 1970: Lineaweaver and Backus
  • 1970: Taniuchi
  • 1970: Sadowsky
  • 1975: Bass, D’Aubrey and Kistnasamy
  • 1983: Gilmore, Dodril and Linley
  • 1984: Compagno
  • 1991: Govender, Kistnasamy and van der Eist
  • 1993: Gordon
  • 1993: Michael
  • 1993: Musick, Branstetter and Colvocoresses
  • 1994: Branstetter and Musick
  • 1994: Last and Stevens
  • 1996: Pollard, Smith and Smith
  • 1998: Hoese and Moore
  • 1998: McEachran and Fechhelm
  • 1998: Smith, Au and Show
  • 1999: Castro, Woodley and Brudek
  • 1999: Gelsleichter, Musick and Nichols
  • 2000: Environment Australia