Sharks, giant trevally, coral trout and other large reef predators present a challenge to reef managers. Their mobility complicates estimates of population status, which makes assessment of man-made and natural changes hard to define. In addition, mobility makes the effectiveness of some management practices, including marine protected areas, hard to evaluate.

Dr Michelle Heupel is tackling questions of large predator mobility in collaboration with other researchers from AIMS and James Cook University, within NERP TE Hub Project 6.1. Individual sharks and fish have been fitted with acoustic transmitters that are detected by an array of acoustic monitoring stations which record the presence and movement of fish between the coast and the reef, and between reefs. These data are used to define the amount of time individuals spend within marine park zone regions and determine how much protection individuals and populations receive from these zones. To date more than 460 tags have been fitted to reef predators from thirteen different species in the Townsville reefs region and the Capricorn Bunker Group.

The team have found a number of patterns in the Townsville reefs data. For example, grey reef sharks don’t move much from home reefs which means that their protection would depend on marine zoning. Bull sharks, on the other hand, move much more within the reef network; into near-shore regions such as Orpheus Island and Cleveland Bay, and alongshore to Moreton Bay; so the time spent in protected zones varies much more. In contrast, blacktip reef sharks have been recorded moving from inshore to Townsville reefs suggesting connectivity between inshore and offshore components of this population.

The work continues but early indications are that reef-based marine park zonation will not provide a single management solution for protecting all these highly mobile predators. Instead it is likely that a combination of management measures will be needed to effectively manage and conserve mobile predator species.

A tagged blacktip reef shark fitted with an acoustic transmitter. Credit: AIMS.
Acoustic monitoring station picking up signals from tagged sharks and fish. Credit: AIMS.

For further information contact:

Project: 6.1 Maximising the benefits of mobile predators to Great Barrier Reef ecosystems: the importance of movement, habitat and environment



Grice, A.A., Clarkson, J.R., Friedel, M.H., Murphy, H.T., Fletcher, C.F. & Westcott, D.A. (in review) Containment: the state of play. Proceedings of 18th Aust Weeds Conference.

Nature World News

05 July 2014

University of Queensland researchers predict an increase in coral deaths this summer.

Researchers studied the Porites coral colonies or 'bommies' in the Great Barrier Reef. Porites are considered to be more resistant to environmental changes than other types of corals. Read more



The University of Queensland

13 January 2014

University of Queensland researchers have found physical evidence in Great Barrier Reef corals of a little-known, long-term climate pattern in the Pacific Ocean.

The Pacific Decadal Oscillation – discovered and named only in the 1990s – describes phases of warm and cool sea surface temperatures that alternate between the Pacific Ocean’s east and west, usually over periods of 20 to 30 years. Read more




The Guardian

19 September 2013

The rampant overfishing of sharks, often solely for their fins, is causing a damaging chain reaction that could significantly degrade coral reef systems, a decade-long Australian-led study has found.

Scientists from Australia and Canada, led by the Australian Institute of Marine Science, discovered that the removal of sharks from two remote reef systems led to a sharp decline in the number of fish that help keep coral healthy. Read more




ABC News

18 November 2014

Marine researchers have been using the annual spawning event on the Great Barrier Reef to test for the effects of dredge spoil and pesticides on coral reproduction.

The release of millions of coral larvae into reef waters provided a chance to replenish and regrow reefs that had been damaged or destroyed. Read more




Tropical Ecosystems Hub researchers are unlocking vital information for species of coral trout on the Great Barrier Reef that has important implications for coral trout conservation and fisheries management in the World Heritage Area.

The team from Project 8.3 Significance of no-take marine protected areas to regional recruitment and population persistence on the Great Barrier Reef is seeking to understand how larval connectivity in networks of marine reserves contribute to biodiversity conservation and sustaining fisheries; and whether the benefits of larval connectivity are influenced by reserve design.

The project is focused on two species of coral trout, Plectropomus leopardus and P. maculatus. These species are primary target species in the Coral Reef Finfish Fishery on the Great Barrier Reef and iconic species that are readily associated with the Great Barrier Reef.

The project team undertook genetic parentage analysis to track dispersal of larval fish from marine reserves; developed a biophysical model to simulate larval dispersal; and established a metapopulation model to forecast future population changes and fishery yield. A metapopulation consists of a group of spatially separated populations of the same species that have some form of migration or mixing behavior among them.

The research provides empirical estimates of larval dispersal within and among three clusters of reefs over 100km apart in the southern Great Barrier Reef region. The research refines an existing biophysical model for this region to better predict regional dispersal; compares observed and predicted patterns of larval dispersal from the biophysical model; and evaluates the effects of marine reserve network design using the metapopulation model.

Preliminary analysis determined a degree of hybridization between the two species. Dispersal studies showed both local retention of larvae within reef clusters and significant connectivity among them. Understanding connectivity is critical to successfully determining recruitment dynamics for these important reef species.

The findings have important implications for understanding the effectiveness of current spatial management within the Great Barrier Reef Marine Park. This is fundamental to understanding how reserves in the Great Barrier Reef are demographically linked to fished areas and therefore can potentially influence fishery yields.

The next stages for this component of the project are to further develop the preliminary metapopulation models to answer questions about whether the establishment of the Great Barrier Reef reserve network has benefited fishery yields in the short- term, compared to a no-reserve scenario.

The project team will also consider the effects of marine reserves in the long-term, accounting for the natural habitat heterogeneity and disturbance events. This will provide a holistic understanding of the fishery and conservation implications of the Great Barrier Reef Marine Park zoning plan on coral trout.



The Conversation

03 September 2013

The world’s coral reefs will quickly dissolve if greenhouse gas emissions continue on current trends, a new simulation has found.

Greenhouse gases cause the ocean to become warmer and more acidic, which bleaches and kills coral reefs, as well as the underwater ecosystems that form around them. Read more





26 March 2014

This animation shows the locations of Crown of Thorns Starfish (COTS) outbreaks on the Great Barrier Reef over a 28 year period as measured by the Long Term Monitorin Program (LTMP) from the Australian Institute of Marine Science (AIMS) using Manta Tow surveys. Each dot on the map represents a reef surveyed for COTS. Since reefs are not surveyed every year the animation combines the data over a 2 year moving window for achieve reasonable coverage of the GBR. Read more




ABC News

14 June 2013

Queensland National Parks Minister Steve Dickson says the crown of thorns starfish continues to be the biggest threat to the Great Barrier Reef.

Mr Dickson is today meeting coral reef researchers on Lizard island, north-east of Cooktown off far north Queensland. Read more