Grey nurse shark-diver interaction research project
Image of 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.
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:
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.
Stage 1: Range testing
Queensland Parks and Wildlife Service | Great Barrier Reef and Marine Parks
Pre-planning discussion with the team.
Equipment required for acoustic arrays: ropes, chain, buoys, floats, acoustic receivers, sync tags…and people power.
Deployment of acoustic arrays. GPS marks taken on the drop.
Ensuring the lines unravel.
Retrieval of the acoustic arrays – BIG DAY!
Largest aggregation ever recorded at Wolf Rock.
Thanks to all of our project team: including staff from QPWS Marine Parks, Technical Support and Operations.
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:
The first array is positioned in close proximity to where the sharks congregate.
The second array is positioned near the boundary of the marine national park zones and grey nurse shark designated areas.
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.
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).
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.
Hydrophone and sub-sonic release equipment used at Wolf Rock.
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.
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.
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
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.
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.
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.