Grey nurse shark
Grey nurse shark Photo: DERM
Common name: grey nurse shark
Scientific name: Carcharias taurus
Family: Odontaspididae
Conservation status: The grey nurse shark is Endangered in Queeensland (Queensland Nature Conservation Act 1992) and Critically Endangered nationally (Commonwealth Environment Protection and Biodiversity Conservation Act 1999). It is also considered a high priority for conservation under the Department of Environment and Resource Management Back on Track species prioritisation framework.
Description
The grey nurse shark has a fusiform (ie spindle-shaped), stout bronze body with a pale undersurface. Brownish spots appear on the upper body and tail fin. The first dorsal fin is closer to the pelvic fins than to pectoral fins.
Five gill slits extend below the base of the pectoral fin. The two dorsal fins are almost equal in size. The shark is approximately 100 cm long when born and grows to a length of about 3.5 metres. Both sexes mature at about 220 cm.
Habitat and distribution
The grey nurse shark occupies the continental shelf from the surf zone down to 190 metres below sea level. They are often in or near steep-sided gutters with sandy substrate or rocky caves.
Knowledge of migrations in Australia is limited but thought to be in response to water temperatures.
Life history and behaviour
A bottom dweller, the grey nurse shark is usually solitary or found in small groups (mostly <20). The species is sexually mature at 4-6 years. Mating occurs between July and October, and they give birth to live young with two young born after 9-12 months. Females may breed only every second year and the species can live for 13-16 years in captivity, possibly longer in the wild.
Grey nurse sharks feed on a range of fast-swimming, schooling teleost (bony) and elasmobranch (cartilaginous) fishes. They are also known to eat squid, crabs and lobsters.
Threatening processes
The grey nurse shark is one of Australia's most endangered marine species.
The grey nurse shark was hunted almost to extinction during the 1960's due to its fierce appearance. Today, activities such as fishing and diving continue to impact on the sharks.
Recovery actions
The Department of Environment and Resource Management and Department of Employment, Economic Development and Innovation introduced fishing and diving laws in Moreton Bay Marine Park and at Wolf Rock off Double Island Point in 2003 to protect the grey nurse shark and its habitat.
Three grey nurse shark designated areas, which are also green zones, are provided in the Marine Parks (Moreton Bay) Zoning Plan 2008 (PDF)*.
Where are the grey nurse shark areas?
There are three grey nurse shark areas in Moreton Bay Marine Park (datum GDA94).
- Cherub's Cave (the area in a 1.2 km radius of the point 27007.67' south, 153028.67' east).
- Flat Rock (the area in a 1.2 km radius of the point 27023.41' south, 153033.07' east).
- Henderson Rock (the area in a 1.2 km radius of the point 27007.92' south, 153028.71' east).
What are the diving requirements?
Grey nurse shark and diver Photo: DERM
Diving restrictions are in place to protect the grey nurse shark and its habitat.
Divers in the grey nurse shark areas must not:
- Dive between 6pm and 6am.
- Touch or feed a grey nurse shark.
- Chase, harass or interrupt the swimming patterns or interfere with a grey nurse shark's natural behaviour.
- Attempt to block cave entrances or gutters, or entrap grey nurse sharks.
- Use mechanical or electro-acoustic apparatus including, but not limited to, scooters, horns and shark-repelling devices (commercial operators may use equipment required for diving under the Workplace Health and Safety Act 1995)
- Dive as part of a group of more than 10 divers (tourist operators may have groups of up to 12 divers, provided the extra divers are either instructors or guides).
Divers can be fined up to $10,000 for breaking these laws.
The department may also develop a system to manage the number of divers visiting the areas where grey nurse sharks congregate. This may include setting distances between dive groups and limiting the number of groups that may use an area at a time.
These changes were introduced to protect the grey nurse shark and its habitat. However, there is scope to increase restrictions if further protection is needed for the species.
Are tourist operators affected?
Yes. Tourism operators with diving as an activity on their Marine Parks permit and dive clubs that are diving in a grey nurse shark area must do the following:
- Ensure that divers are given information about the restrictions for the zone and about entering or using the grey nurse shark area.
- Display the entry and use provisions for grey nurse shark areas in a prominent position on board all diving boats and in dive shops or clubs that operate or promote diving trips in Moreton Bay Marine Park. Tourist operators and dive clubs can be fined up to $1000 for breaking these laws.
- Entry and use provisions sign - Diving in grey nurse shark areas (PDF, 81K)*
- Map showing grey nurse shark areas (PDF, 30K)*
The unauthorised taking, using or keeping of any part of a grey nurse shark could lead to a fine of up to $300,000.
How can I help protect the grey nurse shark?
There are a number of ways you can help protect the grey nurse shark.
- Carry out a volunteer survey (see below).
- Tell friends and family about grey nurse sharks.
- Report any suspicious activities, death or injuries to the Marine Stranding Hotline.
- Contact us with any information about the grey nurse shark.
Divers often record information about grey nurse sharks.
To take part in a survey, download the forms, fill them in and send them to Moreton Bay District Office at 1st Floor, 34 Trafalgar Street Manly Queensland 4163 or fax them to (07) 3131 2889.
Survey data record sheets:
- Grey nurse shark survey data record sheet, and what to do if you catch a grey nurse shark (Excel, 50K)‡
- Commercial operator grey nurse shark survey data record (Excel, 50K)‡
It is also important to record if a grey nurse shark is not seen in a grey nurse shark area.
Record the following information on a sighting or catch of a grey nurse shark:
- Tag number and colour (if any).
- Date, time, location.
- Water depth and temperature.
- Sex, and approximate size.
- Scars, fishing tackle and behaviour.
If possible, include photographs or video footage of the shark. To help identify the shark, photograph the shark's distinguishing features such as scars and dark spots from the first dorsal fin to the end of the tail.
Related information
For information about the management of grey nurse sharks in NSW key aggregation sites visit the NSW Department of Primary Industries (Fishing and Aquaculture).
For information about the management of grey nurse sharks in Commonwealth key aggregation sites visit the Department of the Environment, Water, Heritage and the Arts website.
If a dead grey nurse shark is caught, retain the body and contact the department.
* Requires Adobe Reader
‡ Requires Microsoft Office files viewer
Last updated 25 May 2011