Grey Nurse Shark - Definition

The Grey Nurse, Spotted Raggle-Tooth or Sand Tiger is a large shark inhabiting costal waters worldwide, with many different names in different countries in the world. Despite a fearsome appearance, it is a relatively placid and slow moving animal. Through the 1950s and 60s it was hunted to near extinction in Australian waters by spearfishing, and numbers there are only slowly making a resurgence. The Eastern Australian population is critically endangered, whereas in the west of the continent the population is listed as vulnerable.

The sharks typically congregate in costal waters, at depths of 10-60 metres, although deeper depths have been recorded. Often they will shelter in caves or gutters during the day, and come out at night to feed. During the day they exhibit sluggish behaviour, becoming more active during the night. Research indicates that generally the shark remains within a kilometre of its aggregation site, and stays close to ocean floor.

The species is ovoviviparous, i.e. bearing live young from eggs which hatch inside the uterus. Female sharks have two uteruses. Inside the uterus the young sharks develop and eat each other, so typically only two young sharks are born for each gestation period, which lasts 6-9 months. The shark grows to a length of 3.6m. Males mature at 2.1m and females at 2.2m.

• Barry Bruce, John Stevens, Nick Otway: Site fidelity, residency times and activity space in grey nurse sharks in eastern Australia

External links

• Grey Nurse shark in Byron Bay (http://www.planula.com.au/dive/uwphoto2004/large/grey_nurse_shark.html) - one of the worlds known congregation areas for Grey Nurse sharks