sand shark

Sand tiger sharks Fossil range: Upper Cretaceous–Recent PreЄ Є O S D C P T J K Pg N [1]
Sand tiger shark, Carcharias taurus
Scientific classification
Kingdom: Animalia Phylum: Chordata Class: Chondrichthyes Order: Lamniformes Family: Odontaspididae Müller & Henle, 1839
Genera
Carcharias Odontaspis

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Sand sharks, also known as sand tiger sharks or ragged tooth sharks, are lamniform sharks of the family Odontaspididae (or sometimes - but incorrectly - referred to as Carchariidae). They are found on both sides of the Atlantic coast, but most notably in the Western Indian Ocean and in the Gulf of Maine. There are four species in two genera. Sand sharks are the only known shark to surface for gulps of air. They store the air in their stomachs which allows them to float motionless in the water as they hunt for prey.

Description

Sand sharks have a large second dorsal fin. They grow up to 3.9 metres (13 ft) in adult length^[1]. A Sand Shark can reach up to 250 pounds, which is quite light compared to other sharks. The body tends to be brown in color with dark markings in the upper half. They possess a rudimentary swim bladder^{[citation needed]} - a highly unusual feature in sharks - which enables them to have exquisite control over their buoyancy compared with other sharks. Their needle-like teeth are highly adapted for impaling fish, their main prey. Their teeth, are long, narrow, and very sharp with smooth edges, with one and on occasion two small spurs "denticles" on either side of the jaw. ^[2]

Reproduction

Sand sharks only develop two embryos, one in each uterus. The strongest pups eat other embryos and any other unfertilized eggs in a process called "intrauterine cannibalism" before being born. They have a gestation period of about 9 to 12 months. A female Sand Shark becomes sexually mature when she reaches 2 meters long. At birth, Sand Sharks are already 1 meter long.^[3]

Conservation

The sand tiger shark is managed by the Highly Migratory Species Fishery Management Plan (FMP). However, sand tiger sharks have also been used for fishmeal and oil (from its liver), and its fins are used for the Asian sharkfin trade. Sand tigers are very susceptible to fishery exploitation because they aggregate in large numbers during the mating season at particular coastal spots. These aggregations have been targeted in the past by fisheries.

The sand tiger shark is a U.S. National Marine Fisheries Service species of concern. Species of Concern are those species about which the U.S. Government's National Oceanic and Atmospheric Administration, National Marine Fisheries Service, has some concerns regarding status and threats, but for which insufficient information is available to indicate a need to list the species under the U.S. Endangered Species Act.

Conservation designations

• IUCN^[4]: Vulnerable
• American Fisheries Society: Vulnerable
• A status review under the Endangered Species Act is underway^[when?].

Species

The family contains four species, in two genera:

• Genus Carcharias
  • Sand tiger shark, Carcharias taurus Rafinesque, 1810 ^[5]
  • Indian sand tiger, Carcharias tricuspidatus Day, 1878 ^[6]
• Genus Odontaspis
  • Smalltooth sand tiger or bumpytail raggedtooth, Odontaspis ferox (Risso, 1810) ^[7]
  • Bigeye sand tiger, Odontaspis noronhai (Maul, 1955) ^[8]

References

• NMFS Species of Concern Fact Sheet. 2008
• FishBase

See also

• List of sharks

External links

• Sand shark facts