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Grey nurse shark-diver interaction research project

Image of grey nurse sharks in the gutters at Wolf Rock. Image: Amanda Delaforce.

© Amanda Delaforce.

Grey nurse sharks in the gutters at Wolf Rock.

The grey nurse shark-diver interaction research is a partnership project, which draws on good science and collaboration with industry. It monitors for possible impacts of divers on this critically endangered species to help QPWS protect grey nurse shark designated areas and aggregations.

Image of grey nurse shark with a fish hook in its mouth.

© Carley Kilpatrick.

Grey nurse shark with a fish hook in its mouth.

Background

Why grey nurse sharks?

Grey nurse sharks are a particular focus for QPWS, because the east coast population is thought to contain no more than 1500 to 2000 individual sharks.

Why focus on divers interacting with grey nurse sharks?

Grey nurse sharks are a powerful attraction for divers. There are more than ten commercial dive operators with access to Flat Rock and three with access to Wolf Rock. Currently there are three operators at Flat Rock and one at Wolf Rock that frequent these sites.

There is considerable potential for an increase in diver pressure, particularly during the sharks’ peak aggregation periods. As such it is important to understand the impacts of divers on sharks at key sites to enable QPWS to know if and when limiting access to these sites may be required:

What are the main concerns?

Some divers have indicated to QPWS that sharks may be displaced from shark gutters at Flat Rock. This displacement may be caused by large numbers of divers, sustained presence of divers between 6am and 6pm and/or specific diver behaviour. If displaced from these otherwise protected sites, sharks may be caught by recreational or commercial fishers at sites where fishing is permitted.

Who conducted the research?

The project team is coordinated and managed by QPWS. In-kind support is received from the University of Queensland, Sea Life Sunshine Coast Aquarium, Commonwealth Scientific and Industrial Research Organisation, Grey Nurse Shark Watch and New South Wales Fisheries.

For the Wolf Rock component the Burnett Mary Regional Group and Sea Life Trust - Sunshine Coast Aquarium provided initial funding. A pledge was received from the Threatened Species Commissioner.

What’s the progress?

Wolf Rock, stage 1 of the project, started in 2016 and a final report is expected by mid-2019.

Flat Rock, stage 2, started in March 2018 and uses similar methodology.

Design and procedure

VEMCO Positioning System

The VEMCO Positioning System (VPS) is an affordable, underwater acoustic fine-scale positioning system, capable of providing ‘metres-level position’ resolution of many acoustically tagged animals and/or divers simultaneously.

Two arrays were used for the project:

  1. The first array is positioned in close proximity to where the sharks congregate.
  2. The second array is positioned near the boundary of the marine national park zones and grey nurse shark designated areas.
Diagrams of the VEMCO positioning system (VPS) and procedure.

Diagrams of the VEMCO positioning system (VPS) and procedure (view larger image).

Array 1: VPS Receiver Inner Array

Image of map 1: VPS receiver inner array at Wolf Rock site.

Map 1: VPS receiver inner array at Wolf Rock site (view larger image).

Aim: To obtain detailed movement patterns of tagged grey nurse sharks and tagged scuba divers within each of the four VPS arrays at Wolf Rock and three arrays at Flat Rock.

Image of map 2: VPS receiver inner array at Flat Rock site.

The grey nurse shark-diver interaction research is a partnership project, which draws on good science and collaboration with industry. It monitors for possible impacts of divers on this critically endangered species to help QPWS protect grey nurse shark designated areas and aggregations (view larger image).

Methods:

  • 13 VPS receivers were deployed at the four main areas, where grey nurse sharks are observed congregating at Wolf Rock and similarly at three main areas around Flat Rock.
  • Eight grey nurse sharks were tagged with acoustic transmitters at Wolf Rock and up to 25 are to be tagged at Flat Rock.
  • All dive operators, dive clubs and if possible recreational divers have been asked to attach an acoustic tag to their Buoyancy Control Device (BCD) during all dives at Wolf Rock and Flat Rock during the study.

Array 2: Boundary Receiver Outer Array

Aim: To establish if and when grey nurse sharks leave or return to the protected waters that surround Wolf Rock and Flat Rock.

Image of hydrophone and sub-sonic release equipment used at Wolf Rock.

© Sub Sea Sonics.

Hydrophone and sub-sonic release equipment used at Wolf Rock.

Methods:

  • Five to six receivers are placed in a circular boundary array with overlapping detection areas a few hundred metres inside the boundary and protected waters of the grey nurse shark designated areas.
  • Detection of tagged grey nurse sharks on only the VPS receivers, only boundary receivers or both the VPS receivers and the boundary receivers simultaneously will confirm if and when tagged grey nurse sharks leave or return to the protected waters that surround Wolf Rock and Flat Rock.
Image of VR2AR acoustic release receiver for Flat Rock, along with desk unit and hydrophone.

© VEMCO.

VR2AR acoustic release receiver for Flat Rock, along with desk unit and hydrophone.

  • In addition two receivers are placed at different sites outside of the designated grey nurse shark area and marine national park (green) zone, attempting to detect any sharks that move to these sites and if there is any correlation with diver presence.
  • A Sub Sea Sonic AR-60E acoustic release system is used to enable automated receiver retrieval at Wolf Rock.
  • A VEMCO VR2AR acoustic release system is used to enable automated receiver retrieval at Flat Rock.

Legislation and recovery plan

Image of grey nurse sharks swim protected under marine parks legislation within the Moreton Bay Marine Park.

© Carley Kilpatrick

Grey nurse sharks swim protected under marine parks legislation within the Moreton Bay Marine Park.

Image of map 3: Wolf Rock boundary receiver array.

Map 3: Wolf Rock boundary receiver array (view larger image).

The east coast population of grey nurse sharks are listed as Critically Endangered Internationally (Red List, International Union for the Conservation of Nature) and nationally (EPBC Act) and as Endangered in Queensland under the Nature Conservation Act 1992.

Wolf Rock and Flat Rock are both located within marine national park zones and designated grey nurse shark areas under the Moreton Bay and Great Sandy marine parks (respectively).

There are two additional critical aggregation sites for the grey nurse shark in Moreton Bay Marine Park; they are Cherubs Cave and Henderson Rock. These sites are also located within a marine national park zone (green zone) and a grey nurse shark designated area.

The objectives of a grey nurse shark designated area are:

  • to protect grey nurse shark populations
  • to protect grey nurse shark habitat
  • to minimise harm or distress caused directly or indirectly to grey nurse sharks by diving or other human activities.

Grey nurse shark designated areas

Map showing the Wolf Rock grey nurse shark designated area, near Double Island Point, extends 1.5km around a central point.

The Wolf Rock grey nurse shark designated area, near Double Island Point, extends 1.5km around a central point (view larger image).

Grey nurse shark designated areas further protect the grey nurse shark population, their habitat and minimise harm or distress potentially caused by diving or other human activities.

Activities are highly regulated and restrictions apply to everyone, including divers, entering and using these designated areas. The restrictions are clear.

Do not:

  • touch or feed a grey nurse shark
  • dive between 6pm and 6am
  • chase, harass or interrupt swimming patterns or interfere with a 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
  • dive in a group of more than 10 divers.
map of the coordinates of the Wolf Rock’s grey nurse shark designated area

Coordinates of the Wolf Rock’s grey nurse shark designated area and marine national park zone (green) from Boaties quick guide for Great Sandy Marine Park.

Please refer the Great Sandy Marine Park webpage.

Furthermore:

Fishing is not permitted in the Wolf Rock, Flat Rock, Cherubs Cave and Henderson Rock marine national park zones.

  • Grey nurse sharks are protected in Queensland and New South Wales.
  • It is illegal for a grey nurse shark to be in anyone’s possession without a permit.
  • If you accidentally capture a grey nurse shark you should release it immediately.

Any suspicious activities, death or injuries to grey nurse sharks should be reported to the Marine Stranding Hotline 1300 ANIMAL (1300 26 46 25).