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Dredging on the Great Barrier Reef: Can resource use and conservation co-exist? -Malindi Gammon

Humanity is continuing to encroach on the natural world.

A conflict exists between our treatment of nature and what we demand from nature. Nature is a means to our very survival and yet we continue to destroy it.


Figure 1: This photo illustrates the amount of life which exists even within a small sub-section of the vast reef. Small reef fish are taking refuge in stony coral whilst larger fish school above.
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The Great Barrier Reef (GBR), a world Heritage site acknowledged for its outstanding global significance to biodiversity, is at the centre of this conflict. Covering over 348,000 square kilometres, the Great Barrier Reef (GBR) encompasses approximately 3000 reefs and represents 10% of the world’s coral reefs [1]. It is home to many unique and endangered species [19], creating a spectacular array upon which Australia has built its international identity (Fig.1).  

The GBR also holds monetary and resource value. It is a multiple use marine park which is open to sustainable resource use, supporting a commercial marine tourism and fishing industry. 6 million tourists visit the GBR annually, contributing $6.1 billion dollars to the Australian tourism industry [19].

Plans to expand an existing coal port (Abbot Port) within the GBR region have recently been approved. The resource uses associated with this expansion are proposed to uphold and enhance current conservation efforts throughout the region. Despite strict environmental conditions imposed upon its approval, several factors surrounding the proposal are in conflict with core conservation values:

1.) The reef is already in a state of jeopardized health as a direct result of anthropogenic stressors.

2.) The expansion will lead to some ongoing effects which can’t be mitigated.

3.) The expansion is to allow for capital investment in an unsustainable energy source (coal).


In the instance of Abbot Port expansion, resource use and conservation remain at conflict with one another and can not co-exist.

On 10 December 2013 the Australian government approved a dredging programme for proposed terminals at Abbot Port. This port, located within the GBR marine park region, is used in the exportation of coal [2]. The proposal included dredging of up to 3 million cubic metres of spoil (sand, silt and clay off the seafloor) and disposal 24km offshore [3]. The decision to approve this project has not been taken lightly, and the conclusion was reached under the agreement of 47 strict environmental conditions [2, 3, 4]. Among these conditions were: a 150% net benefit requirement for water quality, approximate monetary contribution to projects supporting reef health of $89 million and measures for protection of marine species and communities [1]. Despite these stringent conditions, the approval has been met with fierce public opposition (Fig. 2).



Figure 2: A crowd protests the approval of dredging at Point Abbot and dumping of spoil within the Great Barrier Reef Marine Park. Photo: The Cairns Post, February 04 2014.

Prior to approval, the proposal attracted 228 submissions in opposition [6]. These submissions, from individuals, consultancies, nongovernmental and governmental agencies, cited adverse environmental impacts as a primary cause for concern [6]. The GBR Marine Park Authority aims to balance economic development with environmental protection, stewardship and conservation. In granting of the proposal, the Australian government plans to uphold this aim.

Two sides to the debate:

Supporting the proposal are the projected benefits for the Australian economy, which are enabled by resource use. Expected outcomes include: an additional $660 million of revenue per year, $123 million household income per year and 2,300 full-time jobs [15]. This revenue will have a flow-on-effect to conservation efforts, with a minimum required $89 million contribution to support projects aimed at reef health. However, if the environmental conditions prove insufficient and the integrity of the reef is jeopardised this would reduce the reefs appeal to tourists. The GBR generates $6.1 billion dollars in tourism revenue per year [19], an amount far exceeding the projected revenue generated by this expansion.

A 2009 outlook report for the GBR cited climate change (increasing sea temperature, ocean acidification and rising sea level), catchment runoff, sedimentation and coastal development as the greatest threats to the health of the GBR [1]. In support of the expansion, those environmental effects which may arise as a result of the expansion, are not a current major concern for the reef. Despite this, approval was only granted under strict environmental conditions. Some of these conditions are unrelated to the possible effects which could be caused by the expansion. They go beyond effect mitigation and aim to improve health of the reef beyond its current state.  In particular, the condition to ensure a net water quality state of 150% its current state will greatly improve the present quality of water within the GBR.  Terrestrial run-off of polluted water and its effect on water quality has a significant adverse influence on many species within the GBR [17].

However, a question arises of the GBR’s current resilience to environmental stressors and whether environmental conditions are enough to uphold this. We must consider the ecosystems current state of health when determining whether Abbot Port expansion and conservation can co-exist. A multitude of anthropogenic stressors already plague this ecosystem: ocean acidification [7], large-scale bleaching events [5], rising seawater temperatures [11], pollution [10] and terrestrial run-off [10]. All of these factors have led to a loss of over half the initial coral cover since 1985 [8] (Fig. 3).


Figure 3: Box plots of the percentiles (25%, 50% and 75%) of coral cover distributions within each year at the GBR. A significant decline since 1985 is evident of 28% coral cover to 13.8% coral cover (De’ath et al, 2012).

On the contrary to approval it is likely that environmental conditions will fail to avoid all negative impacts upon the reef. The effects of sedimentation and vessel traffic cannot be avoided completely and some species of coral [9] and juvenile reef fish [16] are very sensitive to these. The specific condition which addresses sedimentation: “Disposal activities cannot take place when wind and wave conditions or turbidity exceed a possible level…” [2], is not stringent enough to ensure that no harmful effects from sediment plumes arise. Due to the dynamic nature of marine systems, the conditions under which disposal is initiated may not remain constant until that sediment has settled. Extreme cases of sedimentation have caused a shift in the community composition towards dominance of sedimentation resilient species [18].  Although such an extreme effect is unlikely, affected corals are in a prior state of stress and we do not know how close to their maximum tolerance levels they may be. The primary aim of this expansion is to create the infrastructure to allow for more vessel traffic. Juvenile reef fish use sound created by the reef to locate habitat and settle [16] and sound created by coal transporters would likely “drown-out” the sound of the reef, limiting fish larvae’s ability to locate and settle on the reef [12]. An increase in shipping traffic would also increase the chance of invasive species introduction via ship ballast waters [13]. Both these factors are outcomes which need to be considered carefully as there impacts go well beyond the initial stages of development. There remains to be no environmental conditions addressing the effect of shipping on noise pollution under the current approval [2].

Not only will dredging cause an initial and ongoing disturbance to an ecosystem already under considerable anthropogenic stress, but dredging is being undertaken to expand investment into an unsustainable resource. Abbot port is a coal port. Coal is an unsustainable resource due to the increasing pressure it places on natural system. Combustion of coal releases carbon dioxide [14]. Carbon dioxide acts as a green house gas and contributes to global warming [14]. Expansion of this port will cement a continued commitment to the use of fossil fuels. Investing in a resource, use of which leads to increases in atmospheric anthropogenic carbon dioxide and cedes our trajectory towards irreversible climate change [14], is in conflict with conservation values.


The Abbot Port expansion was not approved without careful environmental consideration and stringent conditions aimed to protect the environment and mitigate any negative impacts. If the GBR where existing in isolation, sealed off from current environmental issues plaguing the world, then these conditions would likely suffice. However, this is not the case. The GBR is already subjected to immense anthropogenic stressors as evident by mass bleaching [5], reduction in coral cover [7] and a general decline in reef health. All these factors have reduced the resilience of the reef, and any further impact should be avoided.            

Several outcomes of the Abbot Port expansion are in conflict with conservation values. Despite best-practise attempts to reduce any sedimentation effects, some are likely to occur. Many coral species are sensitive to sedimentation [9] and due to the current state of reef health [8] we don’t know how resilient these species may be. Some ongoing effects cannot be remedied, especially the effect additional boat noise may have on larvae settlement [12]. Finally, the dredging is to allow for the expansion of a port which is used for the exportation of coal. Coal, being a fossil fuel, is an unsustainable energy source. The combustion of coal contributes greatly to global pollution and carbon dioxide levels [14] of which have put the GBR under considerable stress.

Resource use and conservation cannot co-exist within the context of the Port Abbot expansion and the Great Barrier Reef Marine Park.



  1. Australian Government: Great Barrier Reef Marine Park Authority (GBRMPA). (2009). Great Barrier Reef Outlook Report 2009: In brief. Great Barrier Reef Marine Park Authority: Queensland, Australia.
  2. Australian Government: Ministry for the Environment (MFE). (2013a). Abbot Point and Curtis Island projects approved- New safeguards to protect the long-term future of the Great Barrier Reef. [Press release]. Retrieved from: Retrieved on: 02.04.2014.
  3. Australian Government: Ministry for the Environment (MFE). (2013b) Abbot Point and Port of Gladstone Projects Summary. [Press release]. Retrieved from: Retrieved on: 02.04.2014.
  4. Australian Government: Great Barrier Reef Marine Park Authority (GBRMPA). (2014). Permit G14/34897.1. Retrieved from: Retrieved on: 02.04.2014.
  5. Berkelmans, R., & Oliver, J. K. (1999). Large-scale bleaching of corals on the Great Barrier Reef. Coral reefs18(1), 55-60.
  6. The Department of State Development, Infrastructure and Planning (2013). Great Barrier Reef Ports Strategy Consultation Report Version 1.1, summary of consultation responses. Australia: Queensland.
  7. De’ath, G., Lough, J. M., & Fabricius, K. E. (2009). Declining coral calcification on the Great Barrier Reef. Science323(5910), 116-119.
  8. De’ath, G., Fabricius, K. E., Sweatman, H., & Puotinen, M. (2012). The 27–year decline of coral cover on the Great Barrier Reef and its causes.Proceedings of the National Academy of Sciences109(44), 17995-17999.
  9. Erftemeijer, P. L., Riegl, B., Hoeksema, B. W., & Todd, P. A. (2012). Environmental impacts of dredging and other sediment disturbances on corals: a review. Marine Pollution Bulletin64(9), 1737-1765.
  10. Gordon, I. J. (2007). Linking land to ocean: feedbacks in the management of socio-ecological systems in the Great Barrier Reef catchments. Hydrobiologia, 591(1), 25-33.
  11. Hoegh-Guldberg, O., Mumby, P. J., Hooten, A. J., Steneck, R. S., Greenfield, P., Gomez, E., & Hatziolos, M. E. (2007). Coral reefs under rapid climate change and ocean acidification. science318(5857), 1737-1742.
  12. Holles S., Simpson S. & Radford A. (2013). Boat noise disrupts orientation behaviour in coral reef fish. Marine Ecology Progress Series 485: 295-3000.
  13. Lavoie, D. M., Smith, L. D., & Ruiz, G. M. (1999). The potential for intracoastal transfer of non-indigenous species in the ballast water of ships. Estuarine, Coastal and Shelf Science, 48(5), 551-564.
  14. Molina, A., & Shaddix, C. R. (2007). Ignition and devolatilization of pulverized bituminous coal particles during oxygen/carbon dioxide coal combustion. Proceedings of the combustion institute, 31(2), 1905-1912.
  15. Ports Corporation of Queensland (2008). Report for Abbot Point Coal Terminal X110 Expansion. Australia: Queensland. [Retrieved from:].
  16. Radford, C. A., Stanley, J. A., Simpson, S. D., & Jeffs, A. G. (2011). Juvenile coral reef fish use sound to locate habitats. Coral Reefs, 30(2), 295-305.
  17. Schaffelke, B., Mellors, J., & Duke, N. C. (2005). Water quality in the Great Barrier Reef region: responses of mangrove, seagrass and macroalgal communities. Marine Pollution Bulletin, 51(1), 279-296.
  18. Sofonia, J. J., & Anthony, K. (2008). High-sediment tolerance in the reef coral< i> Turbinaria mesenterina</i> from the inner Great Barrier Reef lagoon (Australia). Estuarine, Coastal and Shelf Science78(4), 748-752.
  19. Wachenfeld, D., Johnson, J., Skeat, A., Kenchington, R., Marshall, P., & Innes, J. (2007). Introduction to the Great Barrier Reef and climate change. Climate change and the Great Barrier Reef: a vulnerability assessment, 1-13.







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