Bigeye Thresher, Alopias superciliosus (Lowe 1841)


Bigeye Thresher, Alopias superciliosus. Source: Australian National Fish Collection, CSIRO. License: CC by Attribution-NonCommercial

Summary:

A strong-swimming active shark that can maintain its body temperature above that of the surrounding water.

Identifying features:
Distinct grooves from top of head behind eyes to above gill slits;
Huge eyes extending onto the top part of the head;
First dorsal fin set well back on the body, rear of fin above origin of pelvic fins; pectoral fins very large with broad tips;
Upper caudal-fin lobe about equal in length to rest of body;
Brownish to purplish grey above, uniform creamy-white below.


Cite this page as:
Dianne J. Bray, Alopias superciliosus in Fishes of Australia, accessed 16 Nov 2018, http://fishesofaustralia.net.au/home/species/1849

Bigeye Thresher, Alopias superciliosus (Lowe 1841)

More Info


Distribution

Found worldwide in tropical to temperate oceanic waters, from the surface to 700 metres in Australia; occasionally found inshore.

Size

To 4.9 metres.

Colour

Metallic brownish to purplish-grey above, creamy white below.

Feeding

Thresher sharks have an unusual hunting method – herding schools of smaller pelagic fishes towards the surface then stunning them with the large thrashing tail. The Bigeye Thresher feeds mostly on fishes (hake, scombrids, alepisaurids, clupeids, istiophorids and elasmobranchs) and squid (Smith et al., 2008).

Biology

Thresher sharks are ovoviviparous. The embryos develop in a primitive uterus within the female, where they are nourished by yolk-filled egg capsules that are continually produced by the mother for the developing young to consume. This is a form of intra-uterine (within-the-uterus) cannibalism, known as oophagy or oviphagy (Smith et al. 2008). Female Bigeye Threshers give birth to litters of 2-4 pups.

Fisheries

Taken as a target species and as bycatch throughout its range in gillnet, longline  and trawl fisheries. The flesh is marketed fresh, dried or salted and the fins are sold in the Asian shark fin trade. The species is also caught by recreational anglers.

Conservation

  • EPBC Act 1999 : Not listed
  • IUCN Red List : Vulnerable.
  • The Bigeye Thresher is especially vulnerable to fisheries exploitation (target and bycatch) as it occurs within the range of many largely unregulated gillnet and longline fisheries (Amorim et al. 2009).

    Remarks

    Thresher sharks, like other mackeral sharks, have a highly-developed vascular exchange system called the 'rete mirabile' around the brain and eyes, thought to keep the brain and eyes considerably warmer than the surrounding water temperature during deep dives into cold water.

    Similar Species

    Differs from the other thresher shark species, Alopius pelagios and Alopias vulpinus, in the following combination of characters: a pair of deep grooves on the top of the head; the large, vertically expanded eyes extend onto the top of the head; the long upper lobe of the caudal fin is broader that in the other species; the first dorsal fin is placed further back on the body with the free rear tip positioned above or just before the pelvic fins.

    Etymology

    The specific name superciliosus is from the Latin super (above), and ciliosus (eyebrow), in reference to the deep grooves above the eyes.

    Species Citation

    Alopecias superciliosus Lowe 1841, Proc. Zool. Soc. Lond. 1840 8(89): 39. Type locality: Madeira.

    Author

    Dianne J. Bray

    Bigeye Thresher, Alopias superciliosus (Lowe 1841)

    References


    Amorim, A., Baum, J., Cailliet, G.M., Clò, S., Clarke, S.C., Fergusson, I., Gonzalez, M., Macias, D., Mancini, P., Mancusi, C., Myers, R., Reardon, M., Trejo, T., Vacchi, M. & Valenti, S.V. 2009. Alopias superciliosus. In: IUCN 2011. IUCN Red List of Threatened Species. Version 2011.2. <www.iucnredlist.org>. Downloaded on 14 January 2012.

    Anderson, R.C. & Simpfendorfer, C.A. 2005. Indian Ocean, pp. 140-149. In: S.L. Fowler, M. Camhi, G.H. Burgess, G.M. Cailliet, S.V. Fordham, R.D. Cavanagh, C.A. Simpfendorfer &  J.A. Musick (eds). Sharks, rays and chimaeras: the status of the chondrichthyan fishes. IUCN SSC Shark Specialist Group, IUCN, Gland, Switzerland and Cambridge, UK.

    Clarke, S., Magnusson, J.E., Abercrombie, D.L., McAllister, M. & Shivji, M.S. 2006. Identification of shark species composition and proportion in the Hong Kong shark fin market using molecular genetics and trade records. Conservation Biology 20: 201-211.

    Compagno, L.J.V. 1984. FAO species catalogue. Vol. 4. Sharks of the world. An annotated and illustrated catalogue of shark species known to date. Part 1. Hexanchiformes to Lamniformes. FAO, Rome.

    Compagno, L.J.V. 1990. Shark exploitation and conservation. In: H.L. Pratt, Jr., S.H. Gruber & T. Taniuchi (eds). Elasmobranchs as living resources: Advances in the biology, ecology, systematics and the status of the fisheries. NOAA Techncal Report. NMFS.

    Compagno, L.J.V. 2001. Sharks of the World: An Annotated and Illustrated Catalogue of Shark Species Known to Date. Volume 2. Bullhead, Mackerel and Carpet Sharks (Heterodontiformes, Lamniformes and Orectolobiformes). FAO. Rome, Italy.

    Cortés, E. 2008. Comparative life history and demography of pelagic sharks, pp. 309-322. In: M. Camhi, E.K. Pikitch & E.A. Babcock (eds). Sharks of the Open Ocean. Blackwell Publishing.

    Dulvy, N.K., Baum, J.K., Clarke, S., Compagno, L.J.V., Cortés, E., Domingo, A., Fordham, S., Fowler, S.L., Francis, M.P., Gibson, C., Martinez, J., Musick, J.A., Soldo, A., Stevens, J.D. & Valenti, S.V. 2008. You can swim but you can’t hide: the global status and conservation of oceanic pelagic sharks and rays. Aquatic Conservation: Marine and Freshwater Ecosystems 18(5): 459-482.

    Gilmore, R.G. 1983. Observations on the embryos of the Longfin Mako, Isurus paucus, and the Bigeye Thresher, Alopias superciliosus. Copeia 1983(2): 375–382.

    Gilmore, R.G. 1993. Reproductive biology of lamnoid sharks. Environmental Biology of Fishes 38: 95-114.

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

    Maguire, J.-J., Sissenwine, M.P., Csirke, J., Grainger, R.J.R. & Garcia, S.M. 2006. The state of world highly migratory, straddling and other high seas fisheries resources and associated species. Fisheries Technical Report. FAO, Rome.

    Patterson, J.C., Sepulveda, C.A. & Bernal, D. 2011. The vascular morphology and in vivo muscle temperatures of thresher sharks (Alopiidae). Journal of Morphology 272(11): 1353-1364.

    Smith, S.E., Rasmussen, R.C., Ramon, D.A. & Cailliet, G.M. 2008. The biology and ecology of thresher sharks (Alopiidae). In: Camhi, M.D., Pikitch, E.K. & Babcock, E.A. (eds). Sharks of the Open Ocean: Biology, Fisheries and Conservation. Blackwell Publishing. Oxford, UK.

    Sepulveda, C.A., Wegner, N.C., Bernal, D. & Graham, J.B. 2005. The red muscle morphology of the thresher sharks (family Alopiidae). Journal of Experimental Biology 208(22): 4255–4261.

    Weng, K.C. & Block, B.A. 2004. Diel vertical migration of the Bigeye Thresher Shark (Alopias superciliosus), a species possessing orbital retia mirabilia. Fish. Bull. 102: 221–229.

    White, W.T. 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.

    White, W.T., Last, P.R., Stevens, J.D., Yearsley, G.K., Fahmi & Dharmadi. 2006. Economically Important Sharks and Rays of Indonesia. Australian Centre for International Agricultural Research, Canberra, Australia.

    Quick Facts


    CAAB Code:37012002

    Biology:Live bearer

    Danger:Thrashing tail, sharp teeth

    Depth:0-700 metres

    Fishing:Commercial, recreational

    Habitat:Oceanic, pelagic

    Max Size:To 4.9 metres

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