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Grey Nurse Shark

Grey Nurse Shark

Grey Nurse Shark

(Carcharias taurus)

Outside of Australia, grey nurse sharks are also known as the spotted ragged-tooth shark in South Africa and the sand tiger shark in the United States of America (Otway et al. 2004). The scientific name of the grey nurse shark is Carcharias taurus.

Grey nurse sharks belong to a group of cartilaginous fishes (i.e. fish with skeletons made up of cartilage rather than bone) known as elasmobranchs. As well as sharks, this group also includes rays and skates.

Unique biology

Grey nurse sharks do not reach reproductive maturity until four to six years of age, and only bear young every two years (Pollard et al. 1996; Environment Australia 2002). Grey nurse shark offspring are called pups.

For the grey nurse shark, survival of the fittest begins even before birth, during a phenomenon known as intra-uterine cannibalism. Female grey nurse sharks have two wombs (Pollard et al. 1996). Shark embryos hatch from eggs within each uterus and then the strongest in each womb eats the remaining embryos (Pollard et al. 1996; Environment Australia 2002; ‘Grey nurse on the brink’ 2002). Due to this process, the maximum number of pups born per litter is two (Pollard et al. 1996; Environment Australia 2002).

Where are they found?

Grey Nurse Shark Critical Habitat

Grey Nurse Critical Habitat PDF

Within Australia the grey nurse shark can generally be found in coastal waters off southern Queensland, New South Wales and Western Australia (Pollard et al. 1996; Environment Australia 2002; Otway et al. 2004).

Grey nurse sharks are a schooling fish, and a group of five or more sharks in the same place at the same time is referred to as an aggregation (Otway & Parker 2000). Some of the known aggregation sites are officially recognised as critical habitat under the Environmental Protection and Biodiversity Conservation (EPBC) Act 1999 (Environment Australia 2002). Fish Rock is a critical habitat area and aggregations of up to 40 or more grey nurse sharks are often seen there.

Why are grey nurse sharks an endangered species?

Grey Nurse Shark endangered species prime facts

Grey Nurse Shark endangered species prime facts PDF

Grey nurse sharks are large animals with many large, sharp protruding teeth, and it was largely due to their fierce appearance that they were incorrected labelled ‘man-eaters’ in the past (Environment Australia 2002; Kessler 2005). In the 1950s to the 1970s grey nurse sharks were unfairly targeted by spear and line fishers in attempts to remove the species from the east coast of Australia (Environment Australia 2002; Stow et al. 2006). It was not uncommon for ‘shark hunters’ to take more than 20 sharks from a single gutter in one day (Cropp 1964).

The Australian east coast population of grey nurse sharks experienced a dramatic decline and this, combined with the slow reproductive rate of the species, does not promote a quick or easy recovery of the population. Due to these reasons, in 1984 the grey nurse shark was awarded total protection in New South Wales and became the first shark species in the world to be officially protected (Pollard et al. 1996; Environment Australia 2002).

Globally, the grey nurse shark is listed as ‘vulnerable’ on the World Conservation Union’s Red List of Threatened Species 2000 (Environment Australia 2002; Bansemer & Bennett 2008), and nationally the Australian west coast population is listed as ‘vulnerable’ and the east coast population as ‘critically endangered’ under the EPBC Act 1999 (Stow et al. 2006).

grey nurse shark facts

For more information about Grey Nurse Sharks try visiting these interesting websites.

scuba diving with sharks

Grey Nurse Shark – EPA/QPWS

 


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