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TYPES OF SHARKS
SHARK CHAT FORUM
Threat Level: Medium
The Dusky Shark is also known as
bay-shark, black whaler,
bronze whaler, brown dusky shark, brown shark,
common whaler, dusky ground shark , dusky shark,
- DUSKY SHARK
Scientific Name.... Carcharhinus Obscurus
Family Name...... Carcharhinidae
- General Information: The dusky shark has a
long, streamlined body with a broad, rounded short snout. The
first dorsal fin is much larger than the second with a dermal
ridge found between the two dorsal fins. The upper lobe of the
caudal fin is larger than the lower. The pectoral fins are long
and curved on the trailing edge.
- Size: The average length of dusk sharks are
about 10 feet, and the maximum around 13.6 feet.
- Teeth: The upper teeth of the dusky shark are
triangular and slightly oblique with serrated edges, while the
front teeth are virtually erect. Lower teeth differ since they
have narrow, erect cusps with more finely serrated edges than
the upper teeth. Both sets of teeth become increasingly concave
as they move distally in the jaw.
- Color: The dusky shark is a brown-gray to gray
above and white below. A faint pale stripe extends along the side
of the body to the pelvic fins. In juveniles, the tip of the lower
caudal fin and the undersides of the pectoral fins are notably
dark or dusky, but this is indistinct in adults.
- Feeding Habits: There primary diet consists
of bony fishes, including( catfishes, eels, groupers, lizard fishes,
jacks, tunas, flatfishes, mackerel spade fishes and goatfishes)
and elasmobranchs. They are also a predator of angel sharks, saw
sharks, catsharks, smoothhounds, skates and butterfly rays. Although
less important in the diet, they also eat some crustaceans (including
crabs and lobsters), also cephalopods (including cuttlefishes
and octopuses ) sea stars, snails, and sea snakes. It seems to
have a particular preference for bottom-dwelling prey items and
schooling species including squid, anchovies, sardines, and tuna.
- Social Behaviour: This species segregate to
some degree by sex. They are known to feed actively during the
- Habitat | Migration | Distribution: This shark
is found in western and eastern North Atlantic, western Indian
Ocean, western and eastern Pacific. This species occurs primarily
above coastal shelves in offshore waters adjacent to the open
ocean. It is widely distributed in warm temperate and tropical
waters. It can be found from the surface to depth of 1240 feet.
Like many other large requiem sharks, it migrates into higher
latitudes during warm months and more central latitudes during
- Life Span: Dusky sharks may live as long as
- Reproduction: They are viviparous and females
give birth to a litter of 6-10 young that are up to 3 feet long.
They mate in spring, and give birth after a 16-month gestation
period. Females move into shallow water to drop their young and
mate every two years. Reports on studies of mature females showed
signs of mating wounds on the caudal peduncle and first dorsal
fin. They reported observing three mature females with tooth rake
marks over the eyes or on top of the head.
- Swimming: Because the upper lobe of the caudal
fin is well developed, indicates that the dusky shark is a strong
- Dusky Shark Attacks: They are considered dangerous.
- Population Report: Numbers are dwindling in
many areas. Numbers of this species in the western Atlantic have
fallen because of overfishing.