Dusky Whaler, Carcharhinus obscurus (Lesueur, 1818)

Scientific name: Carcharhinus obscurus
Alternative name/s:
Dusky Shark, Black Whaler
Two juvenile Dusky Whalers Click to enlarge image
Two juvenile Dusky Whalers at a depth of 2m to 3m, Shelly Beach, Sydney, New South Wales, 2 May 2009. Image: Rob Harcourt
© Rob Harcourt

Fast Facts

  • Classification
    Genus
    Carcharhinus
    Species
    obscurus
    Family
    Carcharhinidae
    Order
    Carcharhiniformes
    Class
    Chondrichthyes
    Subphylum
    Vertebrata
    Phylum
    Chordata
    Kingdom
    Animalia
  • Size Range
    The Dusky Whaler grows to 3.65 m in length.

The Dusky Whaler is a 'typical', streamlined, grey-coloured shark. It has a very wide distribution in tropical and warm temperate waters.

Identification

The Dusky Whaler has a long pointed snout, long pectoral fins and a low ridge between the dorsal fins. The first dorsal fin is tall and the tail is heterocercal. The teeth are serrated. Those in the upper jaw are broad and triangular. The lower jaw teeth are more slender.

The species is grey to grey-brown above and pale below. There is an indistinct stripe on the side of the body. It extends forward from above the pelvic fins. In juveniles, the lower lobe of the caudal fin and underside of the pectoral fins are dusky. Fin markings become less distinct as the fish ages.

Sharks

Dusky Shark, Carcharhinus obscurus, denticles.

Image: Sue Lindsay
© Australian Museum

Habitat

It occurs in continental and insular shelf waters from the surface to a depth of 400 m.

Distribution

It is found worldwide in tropical and warm temperate waters. In Australia it is found in all coastal and continental shelf waters. Juvenile Dusky Whalers have been regularly observed in the Shelly Beach/Fairy Bower area of Sydney.

The map below shows the Australian distribution of the species based on public sightings and specimens in Australian Museums. Click on the map for detailed information.

Feeding and diet

Dusky Whalers feed primarily on bony fishes and other sharks but also eat crustaceans and cephalopods.

Life history cycle

The species makes seaonal migrations. Females move into shallow coastal waters in warmer months to give birth. Litters are produced every two to three years.

Danger to humans

Large individuals are potentially dangerous to people but few attacks have been documented.

References

  1. Allen, G.R. 1997. Marine Fishes of Tropical Australia and South-east Asia. Western Australian Museum. Pp. 292.
  2. Daley, R.K., Stevens, J.D., Last, P.R., & G.K. Yearsley. 2002. Field guide to Australian Sharks & Rays. CSIRO Marine Research and Fisheries Research & Development Corporation. Pp. 84.
  3. Hutchins, B. & R. Swainston. 1986. Sea Fishes of Southern Australia. Complete Field Guide for Anglers and Divers. Swainston Publishing. Pp. 180.
  4. Kuiter, R.H. 1996. Guide to Sea Fishes of Australia. New Holland. Pp. 433.
  5. Kuiter, R.H. 2000. Coastal Fishes of South-eastern Australia. Gary Allen. Pp. 437.
  6. Last, P.R. & J.D. Stevens. 1994 Sharks and Rays of Australia. CSIRO. Pp. 513.
  7. Randall, J.E., Allen, G.R. & R.C. Steene. 1997. Fishes of the Great Barrier Reef and Coral Sea. Crawford House Press. Pp. 557.