Publications
Carcharias taurus
Threatened Species Day Fact Sheet
Department of the Environment and Heritage, 2004
Commonwealth: east coast population - Critically Endangered; west coast population - Vulnerable
( Environment Protection and Biodiversity Conservation Act 1999)
NSW: Endangered ( NSW Fisheries Management Act 1994 )
QLD: Endangered ( Nature Conservation Act 1992 )
QLD: Protected ( Fisheries Act 1994 )
VIC: Protected ( Fisheries Act 1995 )
VIC: Threatened ( Flora and Fauna Guarantee Act 1988 )
TAS: Protected ( Fisheries Regulations 1996 )
WA: Protected ( Wildlife Conservation Act 1950)
Grey Nurse Sharks have large, stout bodies, a pointed snout with many rows of visible teeth and small eyes. They are grey to grey-brown on top, paler underneath and sometimes have reddish or brownish spots on their backs. Despite their appearance Grey Nurse Sharks are not a threat to divers or swimmers and actually have a very placid nature.
The sharks have two large dorsal fins of similar size. The tail is distinctive as the top lobe is larger than the bottom. Their upper body is bronze-coloured, while the underside is paler. Juveniles tend to have darker spots on the lower half of their body that fade as they get older.
Grey Nurse Sharks tend to live in shallow inshore waters. Their preferred habitats have sandy-bottomed gutters or rocky caves and are close to inshore rocky reefs or islands. There are two populations of Grey Nurse Sharks in Australia - the east coast population lives along the coast of New South Wales and southern Queensland, and the west coast population is distributed in the southwest coastal waters of Western Australia.
Grey Nurse Sharks are more active at night, when they feed upon fish, smaller sharks, rays, squid and crustaceans.
Male sharks reach sexual maturity at 4 - 6 years of age, and females at 6 - 8 years. Both males and females mature at about 2.2 m and reach a total length of about 3.6m. Pups measure an average of 1m in length at birth.
The breeding of Grey Nurse Sharks is quite unusual. Mating occurs mainly in autumn and is followed by a 9 - 12 month gestation period and the young are born in winter. Towards the end of the gestation period, the more fully developed embryos eat the less developed embryos and unfertilised eggs within the female shark's uterus. As a result, only two pups are produced per litter - one in each uterus. Grey Nurse Sharks tend to breed only once every two years. This is the lowest reproductive rate of any shark and makes it more susceptible to external pressures that increase mortality.
Grey Nurse Sharks have suffered a decline over recent years, resulting in the listing of the east coast population as 'critically endangered'. A New South Wales Fisheries survey in 2000 revealed that the number of Grey Nurse Sharks in New South Wales could be as low as 292 individuals.
Although the sharks are protected today, they were commercially fished quite extensively in the past. Illegal fishing still occurs, and accidental capture by both commercial and recreational fishers also poses a serious threat.
Key habitat sites for Grey Nurse Sharks are often favoured fishing sites, and there have been various reports of recreational fishers accidentally catching Grey Nurse Sharks. Scuba divers have observed a large number of the sharks with hooks and lines in their mouths. Some survive the injuries they sustain from fishing gear, but many don't. An autopsy of a Grey Nurse Shark in 2000 revealed that the cause of death was the perforation of the stomach wall by numerous small hooks of the type used by recreational fishers.
In the 1950s and 1960s, the misconception that Grey Nurse Sharks were 'man-eaters' led to intensive fishing efforts by spearfishers using explosive headed spears. Their placid nature made them easy targets.
Beach safety nets, designed to keep out sharks that are dangerous to humans, can also trap the harmless Grey Nurse Shark.
New South Wales Fisheries
Ph: (02) 4916 3877
Visit: www.fisheries.nsw.gov.au/
Queensland Environmental Protection Agency
Ph: 1300 360 989
Email: greynurseshark@epa.qld.gov.au
Alison Colyer, NSW & ACT Coordinator
Threatened Species Network
Ph: (02) 8202 1222
Email: tsnnsw@wwf.org.au
Keryn Hyslop, QLD Coordinator
Threatened Species Network
Ph: (07) 3221 0573
Email: tsnqld@wwf.org.au
Raquel Carter, WA Coordinator
Threatened Species Network
Ph: (08) 9387 6444
Email: tsnwa@wwf.org.au
You can also find out more information about Australia's threatened species by calling the Department of the Environment and Heritage Community Information Unit on freecall 1800 803 772 or by visiting www.deh.gov.au/biodiversity/threatened.
This fact sheet is also available for download as a PDF file. You will need Adobe Acrobat Reader on your computer to view the PDF file.