Despite being relatively common, the hardnose shark is a little-known species (3). A typical member of the requiem shark family, the Carcharhinidae (2)(4), this small, slender shark possesses a long, narrow and stiff pointed snout, hence its common name (5). It is typically grey to grey-brown, with a white underside. The pectoral and caudal fins have distinctive white edges, while the small dorsal fin has faint black edges (2). Another trait which characterises this shark is the extremely long rear tips of the two dorsal fins(2)(3). Vision is important for the hardnose shark; it has large eyes measuring up to 2.5 percent the length of the entire body, giving this agile shark a predatory advantage and enabling it to catch nimble, athletic prey such as squid (3).
The hardnose shark is a gregarious species that forms large groups, often with other species such as the spottail shark (Carcharhinus sorrah) and the Australian black tip shark (Carcharhinus tilstoni). Swimming down to depths of up to 170 metres it feasts on prey such as bony fish, lobster, squid and cuttlefish (2)(3).
During mating, the female is fertilised internally through copulation with the male (2). The species is viviparous meaning that the sharks give birth to live young (3). The female undergoes a long twelve month pregnancy before typically giving birth to two pups (1)(8), measuring around 45 centimetres in length (3). The mother has a biennial cycle, meaning she can reproduce once every two years (8). Little is known about the hardnose shark’s life span but it is estimated to live for up to twenty years (1).
The slender hardnose shark belongs to one of the most sought after shark families in tropical fisheries (7). Shark fishing is a major conservation threat in tropical waters and is the primary cause of dwindling numbers of shark populations (9). Shark fin is one of the most expensive fishery products and is used to make shark fin soup, a delicacy with a 2,000 year old Chinese tradition (9)(10). Fortunately for the hardnose, it is not one of the favoured species for shark fin and is of limited interest to fisheries due to its small size (2)(9). Despite this, the species is still fished for its meat for human consumption by countries such as Pakistan, India and China and is often caught as bycatch and discarded by fisheries specialising in more expensive species such as tuna (1)(2)(9). Throughout its range in the Indo-West Pacific the hardnose shark is caught using various fishery methods such as trawls, long lines and gillnets (6).
The hardnose shark is currently not classed as a threatened species (1), but its long two-year reproductive cycle means it is more vulnerable to fishing pressures than other species as its population is slow to increase (6). Therefore the conservation status of the hardnose shark may change to threatened in the near future if legislation is not introduced to limit its exploitation (6). This, however, cannot be done until more information is acquired about the impact of fisheries on population numbers (1)(6).
Cavanagh, R.D., Kyne, M., Fowler, S.L., Musick, J.A. and Bennett, M.B. (2003) The Conservation Status of Australasian Chondrichthyans. Report of the IUCN Shark Specialist Group, Australia and Oceania Regional Red List Workshop. The University of Queensland, School of Biomedical Sciences, Brisbane, Australia.
Carpenter, K.E. and Niem, V.H. (1998) The Living Marine Resources of the Western Central Pacific. FAO Species Identification for Fishery Purposes. FAO, Rome.
Economakis, A.E. and Lobel, P.S. (1998) Aggregation behaviour of grey reef shark, Carcharhinus amblyrhynchos, at Johnston Atoll, Central Pacific Ocean. Environmental Biology of Fishes, 51: 129-139.
Fowler, S.L., Reed, T.M. and Dipper, F.A. (1997) Elasmobranch Biodiversity, Conservation and Management. Proceedings of the International Seminar and Workshop, Sabah, Malaysia.
Clarke, S.C., Magnussen, J.E., Abercrombie, D.L., McAllister, M.K. and Shivji, M.S. (2004) Identification of shark species composition and proportion in the Hong Kong shark fin market based on molecular genetics and trade records. Conservation Biology, 20(1): 201-211.
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