Dusky Whaler, Carcharhinus obscurus (Lesueur 1818)


Other Names: Black Whaler, Black Whaler Shark, Bronze Whaler, Common Whaler Shark, Dusky Shark, River Whaler, Slender Whaler Shark, Whaler Shark

A Dusky Whaler, Carcharhinus obscurus, Sydney, New South Wales, August 2006. Source: petersimpson / iNaturalist.org. License: CC by Attribution-NonCommercial

Summary:
A large predatory bronze-grey to dark grey shark with a white underside, a faint pale stripe extending anteriorly on the side, and dusky fins tips in juveniles, but less so in adults. The species has an interdorsal ridge and dusky tip on the second dorsal fin.
Juvenile Dusky Whalers in the Cabbage Tree Bay Aquatic Reserve, Fairy Bower, Sydney.

Cite this page as:
Bray, D.J. 2022, Carcharhinus obscurus in Fishes of Australia, accessed 05 Oct 2022, https://fishesofaustralia.net.au/home/species/1953

Dusky Whaler, Carcharhinus obscurus (Lesueur 1818)

More Info


Distribution

Found around Australia including the Lord Howe Province and Norfolk Island in the Tasman Sea, although rare in Tasmanian waters. Elsewhere the species has a patchy distribution in tropical and temperate seas of the Indian and Pacific Oceans. The species is coastal and pelagic, occurring along continental margins from the surf zone to well offshore.

Features

Vertebrae 173–194 (86–97 precaudal)

Snout moderately long (length to mouth 5–10% TL), bluntly rounded; labial furrows short and inconspicuous; upper teeth broadly triangular with serrated cusps; 1st dorsal-fin origin over free rear tip of pectoral fin, both sets of fins tapering distally, apices pointed or narrowly rounded; interdorsal ridge present.

Size

Reaches 3.65 m TL.

Colour

Bronzy grey to dark grey above, white below; faint pale stripe extending anteriorly on flank from pelvic fins; fins tips mostly dusky in juveniles, but less so in adults (dusky tip on second dorsal fin).

Biology

Males mature at 265–280 cm TL, females mature at 257–310 cm TL. Reproduction is placental viviparous with a long gestation of 22 months, litter sizes of 2–18 pups, a two or three year reproductive cycle, and size-at-birth of 70–100 cm TL.

Fisheries

Targeted and taken as bycatch in commercial and small-scale pelagic longline, purse seine, and gillnet fisheries worldwide - mostly as bycatch of commercial pelagic fleets in offshore and high-seas waters. The species may be retained for the meat and fins. 

Remarks

The Dusky Whaler is one of the pelagic sharks most vulnerable to overfishing.

Species Citation

Squalus obscurus Lesueur, 1818, J. Acad. nat. Sci., Philad., 1: 223, pl. 9. Type locality: No locality (= east coast U.S.A.)

Author

Bray, D.J. 2022

Resources

Atlas of Living Australia

Dusky Whaler, Carcharhinus obscurus (Lesueur 1818)

References


Benavides, M.T., Horn, R.L., Feldheim, K.A., Shivji, M.S., et al. 2011. Global phylogeography of the dusky shark Carcharhinus obscurus: implications for fisheries management and monitoring the shark fin trade. Endangered Species Research 14(1): 13-22.

Compagno, L.J.V. 1984. FAO Species Catalogue. Sharks of the World. An annotated and illustrated catalogue of shark species known to date. Carcharhiniformes. FAO Fisheries Synopsis No. 125. Rome : FAO Vol. 4(2) 251-655 pp.

Compagno, L.J.V., Dando, M. & Fowler, S. 2005. A Field Guide to the Sharks of the World. London : Collins 368 pp.

Compagno, L.J.V. & Niem, V.H. 1998. Family Carcharhinidae. pp. 1312-1360 in Carpenter, K.E. & Niem, V.H. (eds). The Living Marine Resources of the Western Central Pacific. FAO Species Identification Guide for Fisheries Purposes. Rome : FAO Vol. 2 687-1396 pp.

Garrick, J.A.F. 1982. Sharks of the genus CarcharhinusNational Marine Fisheries Service (U.S.). Technical Report 445: 1-194 figs 1-83

Geraghty, P.T., Macbeth, W.G., Harry, A.V., Bell, J.E., Yerman, M.N. & Williamson, J.E. 2013. Age and growth parameters for three heavily exploited shark species off temperate eastern Australia. – ICES Journal of Marine Science, doi.10.1093/icesjms/fst164.

Grant, E.M. 1975. Guide to Fishes. Brisbane : Queensland Government, Co-ordinator General’s Department 640 pp.

Hoschke, A., Whisson, G. & Moore, G.I. 2019. Complete list of fishes from Rottnest Island. pp. 150-161 in Whisson, G. & Hoschke, A. (eds). The Rottnest Island fish book. 2nd ed. Perth : Aqua Research and Monitoring Services.

Hutchins, J.B. & Swainston, R. 1986. Sea Fishes of Southern Australia. Complete field guide for anglers and divers. Perth : Swainston Publishing 180 pp.

Junge, C., Donnellan, S.C., Huveneers, C., Bradshaw, C.J.A., et al. 2019. Comparative population genomics confirms little population structure in two commercially targeted carcharhinid sharks. Marine Biology 166(2): https://doi.org/ 10.1007/s00227-018-3454-4

Kailola, P.J., Williams, M.J., Stewart, P.C., Reichelt, R.E., McNee, A. & Grieve, C. 1993. Australian Fisheries Resources. Canberra : Bureau of Resource Sciences and the Fisheries Research and Development Corporation 422 pp.

Kuiter, R.H. 1993. Coastal Fishes of South-eastern Australia. Bathurst : Crawford House Press 437 pp.

Larson, H.K., Williams, R.S. & Hammer, M.P. 2013. An annotated checklist of the fishes of the Northern Territory, Australia. Zootaxa 3696(1): 1-293.

Last, P.R. & Stevens, J.D. 1994. Sharks and Rays of Australia. Canberra : CSIRO Australia 513 pp. 84 pls.

Last, P.R. & Stevens, J.D. 2009. Sharks and Rays of Australia. Collingwood : CSIRO Publishing Australia 2, 550 pp.

Lesueur, C.A. 1818. Descriptions of several new species of North American fishes. Journal of the Academy of Natural Sciences of Philadelphia 1(2): 222-235 fig. 9-10 See ref at BHL

Macbeth, W.G., Vandenberg, M. & Graham, K.J. 2008. Identifying Sharks and Rays; a Guide for Commercial Fishers. Sydney : New South Wales Department of Primary Industry 71 pp.

McAuley, R. Lenanton, R., Chidlow, J. Allison, R. & Heist, E. 2005. Biology and stock assessment of the thickskin (sandbar) shark, Carcharhinus plumbeus, in Western Australia and further refinement of the dusky shark, Carcharhinus obscurus, stock assessment. Final FRDC Report – Project 2000/134. Fisheries Research Division Western Australian Fisheries and Marine Research Laboratories Fisheries Research Report no. 151.

Pepperell, J. 2010. Fishes of the Open Ocean a Natural History & Illustrated Guide. Sydney : University of New South Wales Press Ltd 266 pp.

Ramsay, E.P. & Ogilby, J.D. 1887. On an undescribed shark from Port Jackson. Proceedings of the Linnean Society of New South Wales 2 2(1): 163-164 (described as Carcharias macrurus, type locality  Port Jackson, NSW).

Randall, J.E., Allen, G.R. & Steene, R. 1990. Fishes of the Great Barrier Reef and Coral Sea. Bathurst : Crawford House Press 507 pp. figs.

Randall, J.E., Allen, G.R. & Steene, R. 1997. Fishes of the Great Barrier Reef and Coral Sea. Bathurst : Crawford House Press 557 pp. figs.

Reid, D.D., Robbins, W.D. & Peddemors, V.M. 2011. Decadal trends in shark catches and effort from the New South Wales, Australia, Shark Meshing Program 1950-2010. Marine and Freshwater Research 62: 676-693.

Rigby, C.L., Barreto, R., Carlson, J., Fernando, D., Fordham, S., Francis, M.P., Herman, K., Jabado, R.W., Liu, K.M., Marshall, A., Pacoureau, N., Romanov, E., Sherley, R.B. & Winker, H. 2019. Carcharhinus obscurus. The IUCN Red List of Threatened Species 2019: e.T3852A2872747. https://dx.doi.org/10.2305/IUCN.UK.2019-3.RLTS.T3852A2872747.en. Accessed on 26 September 2022.

Rogers, P.J., C. Huveneers, S.D. Goldsworthy, W.W.L. Cheung, G.K. Jones, J.G. Mitchell & L. Seuront.  2013. Population metrics and movement of two sympatric carcharhinids: a comparison of the vulnerability of pelagic sharks of the southern Australian gulfs and shelves. Marine and Freshwater Research 64(1): 20-30 http://dx.doi.org/10.1071/MF11234

Rogers, P.J., Huveneers, C., Goldsworthy, S.D., Mitchell, J.G. & Seuront, L. 2013. Broad-scale movements and pelagic habitat of the dusky shark Carcharhinus obscurus off Southern Australia determined using pop-up satellite archival tags. Fisheries Oceanography 22(2): 102-112. http://dx.doi.org/10.1111/fog.12009

Simpfendorfer, C.A. 2000. Growth rates of juvenile dusky sharks, Carcharhinus obscurus (Lesueur, 1818), from southwestern Australia estimated from tag-recapture data. Fish Bulletin 98: 811–822.

Simpfendorfer, C.A., McAuley R.B., Chidlow J. & Unsworth P. 2002. Validated age and growth of the dusky shark, Carcharhinus obscurus, from Western Australian waters. Marine and Freshwater Research 53: 567-573.

Stevens, J.D. 1994. Families Carcharhinidae, Triakidae, Scyliorhinidae. pp. 120-138 figs 76-107 in Gomon, M.F., Glover, C.J.M. & Kuiter, R.H. (eds). The Fishes of Australia's South Coast. Adelaide : State Printer 992 pp. 810 figs.

White, W. 2008. Shark Families Heterodontidae to Pristiophoridae. pp. 32-100 in Gomon. M.F., Bray, D.J. & Kuiter, R.H (eds). Fishes of Australia's Southern Coast. Sydney : Reed New Holland 928 pp.

Whitley, G.P. 1940. The Fishes of Australia. Part 1. The sharks, rays, devil-fish, and other primitive fishes of Australia and New Zealand. Sydney : Roy. Zool. Soc. N.S.W. 280 pp. 303 figs. (as Galeolamna macrurus)

Whitley, G.P. 1944. New sharks and fishes from Western Australia. The Australian Zoologist 10(3): 252-273 figs 1-6 [described as Galeolamna (Galeolamnoides) eblis, type locality off Bald Head, toward Breaksea Island, WA].

Quick Facts


CAAB Code:37018003

Conservation:IUCN Endangered

Depth:0-500 m

Fishing:Commercial fish

Habitat:Pelagic, coastal, offshore

Max Size:420 cm TL

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CAAB distribution map