Sandtiger or grey nurse shark
(Carcharias taurus)
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Given Names
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French
: Requin Taureau.
German: N/A
Spanish : Tiburon toro; Toro bacoto; Salroig de sorra;
Salraig.
Italian: Squalo toro; Pisci tauru.
Other Scientific Names : Eugomphodus taurus (Rafinesque,
1810); Odontaspis taurus (Rafinesque, 1810) |
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Diagnosis
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| A fairly
large, stocky shark with dorsal fins and anal fin essentially subequal in
size; dorsally-flattened conical snout with mouth extending behind the eyes;
small eyes (diameter about 1%TL) without nictitating eyelids and of rather
feline appearance; teeth large, unserrated; protruding and dagger-like
with prominent pair of lateral cusps; fourth upper-tooth (intermediate)
much smaller than third and fifth. First dorsal fin origin nearer to pelvic
fins that pectorals; pectoral fins rather short, broad and paddle-like in
shape. No keels on caudal peduncle. Caudal fin strongly asymmetrical, upper
lobe measuring ca. 27%TL and ventral lobe ca. 11%; precaudal pit present.
Colour dorsally ranging from light brown, sandy-brown or grey-brown and with
a conspicuous bronzy sheen in life; darker mottled spots often present on
body and caudal fin which may fade with maturity. Ventral surfaces
white; demarcation between dorsal and ventral pigment abrupt in places although
fading rapidly after death. |
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Size
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| Attaining
320 cm TL but generally smaller to about 300 cm; size at birth 95 to 105cm. |
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Distribution
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| Océan
Atlantique : Restricted to southern areas below, where rare or occasional.
Northern range limit probably at southern Iberian peninsula; abundance
increases slowly southwards along the coasts of Morrocco, Mauritania, Western
Sahara and to Senegal, where considered moderately common; also found at
the Cape Verde Islands and Canaries; range continues south to equatorial
West Africa.
Mer Méditerranée : Generally rare in the region
and perhaps declining. Occasional and sporadic from Gibraltar along the Spanish
coasts to the Gulf of Lyons; also Balearics; Morocco, Melilla, Algeria and
Tunisia along North African coasts; Western Italy (Tyrrhenian Sea, Sardinia,
Elba, Ponza, and other insular sites); Sicily, Isole Pelagie and Malta ;
Ionian Sea coastline of Italy (Calabria); Adriatic Sea but increasingly scarce
there. Greeks seas including the Aegean, but sporadic; generally insular
(e.g., Cyclades, Dodecanese).
Océan Indien : South east Asian coasts.
Océan Pacifique : North American coasts and the south
east coasts of the South America.
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Biology
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| A coastal,
littoral shark inhabiting zones from the surfline to some distance offshore,
but within a depth range of surface to 200m, though normally less than
70m. Sandtigers are normally encountered on or near the bottom but also
sometimes close inshore at the surface. Mediterranean examples are more
commonly found in close association with insular or headland localities,
particularly over rocky or boulder-strewn seabeds but also sandy flats in
bays and around offshore submerged reefs and banks where fish are plentiful.
These sharks form large aggregations for courtship and feeding elsewhere
in their range in regions where they are common (such as off South Africa
and Australia), but Eastern Atlantic and Mediterranean captures infer a
considerably more diffuse population as even in areas where this shark is
taken annually (Sicily), captures are nominal. It is likely that this
species migrates southwards in the winter months, but catch-data throughout
the region is insufficient to establish seasonal or areal trends. A strong
but slow swimmer that is often found grouper-like, hanging virtually motionless
just above the bottom, this species is more active nocturnally; it will gulp
air at the surface and retain it within the stomach to acheive near neutral
buoyancy, rather as by means of a makeshift swimbladder. Oviphagous, with
uterine cannibalism. Having consumed other fertilised ova, one dominant embryo
survives in each egg-case and, soon after hatching within the uterus, develops
teeth. It then actively devours other hatched siblings in utero, eventually
surviving as one of just two offspring - i.e., one in each uterus. Gestation
is about 9 months to one year, with pups born at a comparatively large size
(ca. 100cm). Females mature at about 220 cm; males 220-260cm or above. |
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Feeding
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| Sandtigers
are active predators of a wide range of bony fish and elasmobranchs, including
sea-basses, mullets, jacks, flatfish and some scombroids; small sharks
such as Mustelus spp.; rays, cephalopods, crabs and other benthic
invertebrates. |
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Similar Species
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| The Smalltooth
sandtiger (Odontaspis Ferox) and the Odontaspis noronhai. |
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Endangerment
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| Endangered.
Several countries have designated it a protected species. |
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Danger to humans
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| Harmless.
But this is a big shark, and it has all ready attaqued human. Do not miss
with these sharks. |
This page has been designed by Fadi Fakhoury
with the help of the Shark Trust
and its chairman Mr
Ian Fergusson.
The Shark Trust
36 Kingfisher Court,Hambridge
Road,
Newbury, Berkshire,RG14
5SJ, UK.
Tel(+44) 01635 551150
Fax(+44) 01635 550230
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