5.8.3 Impacts of shipping

A number of impacts result from shipping activities in the Region. These include acute and chronic effects from ship groundings, operational and accidental discharges of ballast and bilge water, damage to reef structure, damage to seafloor,1472 vessel strikes with marine megafauna 1473 and noise pollution.325,1474 

Physical disturbance and damage from shipping can be caused by ship groundings, anchor damage and propellor wash. Deployment of a ship’s anchor resuspends sediments and can damage the seabed as changing tides and shifting winds cause vessels to swing and drag chains across the substratum.1475 Ship groundings provide both an immediate and long-term impact on benthos and can potentially damage Indigenous and historic heritage sites. The initial grounding causes loss in the biota of the benthic area and can create fields of unconsolidated substrate (such as coral rubble). Since 2019, there has been one grounding, one collision (Figure 5.23) and 16 near misses in the Region.1382 Near misses can be useful in understanding when and where there is an increased potential for environmental damage from groundings and spills. A near miss may occur when a vessel becomes disabled, almost runs aground, and requires assistance as a result of weather, mechanical breakdown or negligence.

1 grounding and 1 collision occurred in the Region since 2019

Figure 5.23
Ship groundings and collisions, 1985 to 2023

Bars represent groundings and collisions reported to the Reef Authority, Maritime Safety Queensland and the Australian Maritime Safety Authority involving ships within the World Heritage Area. All collisions were between ships and smaller vessels rather than between two ships. Groundings include those within designated port areas. Source: Reef Authority (2023)1382

: A two toned stacked bar graph showing the number of incidents from either groundings (blue) or collisions with the seafloor (red) from 1985 to 2023. The y-axis is number of incidents from 0-6. The x-axis is time in years from 1985 to 2023.

Antifouling paint, which is applied to ships to control or prevent attachment of unwanted organisms,1476 can cause long-term damage by inhibiting future recruitment of benthic organisms. These impacts were observed at the grounding site of the Shen Neng 1 on Douglas Shoal in 2010 (Box 5.5).

Shipping is the main source of antifoulant paint in the Region. Leaching and release of antifouling components from vessels occur while moving along shipping lanes, anchored in anchorage areas and at berth in port.1477 In 2020, a study found tributyltin, a chemical in antifouling paint, present in the water column and/or in the sediment in the five main ports in the Region.1477

The likelihood of vessel strike increases during whale migration season and may rise further if growth in shipping is coupled with increasing whale populations, such as the humpback whale.1473 The Inner Shipping Route overlaps with migration routes for humpback whales, including a key breeding aggregation in the Capricorn Bunker Group. In one study, the areas of highest relative risk in the Reef were found to be between the Whitsunday Islands and offshore Mackay. Understanding the risk of vessel strike affecting cetaceans in some other areas, such as the Capricorn Bunker Group, remains a knowledge gap.1478

Noise pollution has been found to disrupt breeding, migration and settlement behaviours of fish and crustaceans. It also causes stress and disorientation in cetaceans.1479 However, these impacts are poorly understood in the Region.

Pollution, such as oil spills and marine debris as a result of shipping activities, reduces water quality and presents a hazard for marine organisms. Four oil spill incidents have been reported since 2019.1382 Plastics, which are the most common item in marine debris, have known impacts (that is, ingestion and entanglement) on marine organisms in the Region.1480 One incident was reported of a vessel discharging ballast water within the Region, which represents a risk as marine pests and diseases could be introduced. The potential impact of introduced marine species being transported by ships is discussed in Section 3.6.3.

Box 5.5

Douglas Shoal Environmental Remediation Project

The Douglas Shoal Environmental Remediation Project is one of the most innovative and large-scale coral reef restoration efforts ever undertaken. The project was initiated after a financial settlement with the ship’s owners and insurers in 2016, in response to the grounding of the Shen Neng 1 in 2010. The project identified that bulk removal of ship-grounding-generated rubble and antifouling paint contamination was likely the best solution to promote natural recovery of the shoal. 

Douglas Shoal and its surrounding waters are part of the Sea Country of the Bailai, Gurang, Gooreng Gooreng and Taribelang Bunda peoples. A key project objective was to ensure partnerships with Traditional Owners to deliver critical project activities and support First Nations people’s capacity building (see Caring for Sea Country story in Chapter 9). In addition to delivery of cultural awareness training for non-Indigenous project staff, Gidarjil Development Corporation Rangers delivered crucial support, including underwater remotely operated vehicle (ROV) services, marine fauna observation, and offshore logistical support via their Guardian Warrior vessel. 

The Reef Authority conducted surveys and logistical planning with Advisian and pre-remediation monitoring and turbidity plume modelling with BMT Australia in the lead-up to remediation activities on Douglas Shoal. In early September 2023, the Reef Authority’s primary remediation contractor, Boskalis, undertook targeted remediation of Douglas Shoal using a specialised trailing suction hopper dredge vessel. Subsequent underwater sonar and ROV surveys indicate successful removal of ship-groundinggenerated rubble, with minimal impact to adjacent high‑value marine benthic habitats. Further extensive post-remediation surveys on the shoal are expected to support initial positive remediation outputs. 

All rubble and associated antifouling paint contamination removed from Douglas Shoal were deposited into specially designed and constructed ponds on land leased from the Gladstone Ports Corporation. All dewatering and onshore project activities and subsequent preparation of technical papers are expected to be completed in 2024. 

Shipping also contributes to broader greenhouse gas emissions,1481 but quantitative data for the Region are a gap. In 2021–22, the national domestic maritime sector emitted around 2 million tonnes of greenhouse gas emissions, or 2.2 per cent of Australia’s transport emissions and 0.4 per cent of total national emissions.1482,1483 The 2023 IMO Strategy on Reduction of GHG Emissions from Ships, adopted by Australia and other member states, includes a target to reach net-zero greenhouse gas emissions from international shipping by or around 2050.1484

Since 2019, an emerging impact associated with shipping activities has been the use of sulfur scrubbers for vessel exhaust gas cleaning.1485 The scrubbers have been implemented internationally as best practice as part of a transition towards lower emissions. The scrubbers discharge sulfur compounds directly into the marine environment. The discharged water is considered to have minimal effect on the marine environments because it is estimated to be buffered and diluted to almost undetectable levels within seconds to minutes of discharge.1486 While the location of shipping routes, for the most part, are not in proximity to coral reef habitats, assessments of this hazard have not been specific to the context of the Reef and sensitive habitats.1485

  • 325. Sutcliffe, P.R., Hooper, J.N. and Pitcher, C.R. 2010, The most common sponges on the Great Barrier Reef seabed, Australia, include species new to science (Phylum Porifera), Zootaxa 2616(1): 1–30.
  • 1382. Great Barrier Reef Marine Park Authority 2023, Maritime Incident Database, Great Barrier Reef Marine Park Authority.
  • 1472. Byrnes, T.A. and Dunn, R.J. 2020, Boating-and shipping-related environmental impacts and example management measures: A review, Journal of Marine Science and Engineering 8(11): 908.
  • 1473. Peel, D., Smith, J.N., Erbe, C., Patterson, T.A., Childerhouse, S. 2019, Quantification of risk from shipping to large marine fauna across Australia: Final Report.
  • 1474. Peel, D. Erbe, C., Smith, J.N., Parsons, M.J.G., Duncan, A.J., Schoeman, R.P. and Meekan, M 2021, Characterising anthropogenic underwater noise to improve understanding and management of acoustic impacts to marine wildlife. Final Report to the National Environmental Science Program, Marine Biodiversity Hub, National Environmental Science Program, Tasmania.
  • 1475. Broad, A., Rees, M.J. and Davis, A.R. 2020, Anchor and chain scour as disturbance agents in benthic environments: trends in the literature and charting a course to more sustainable boating and shipping, Marine Pollution Bulletin 161: 111683.
  • 1476. International Maritime Organization. Marine Environment Protection Committee 2005, Anti-fouling Systems: International Convention on the Control of Harmful Anti-fouling Systems on Ships, 2001 (AFS 2001) and Guidelines for Survey and Certification of Anti-fouling Systems on Ships (resolution MEPC. 102 (48)), Guidelines for Brief Sampling of Anti-fouling Systems on Ships (resolution MEPC. 104 (49)), and Guidelines for Inspection of Anti-fouling Systems on Ships (resolution MEPC. 105 (49)), IMO Publishing.
  • 1477. Kroon, F.J., Berry, K.L.E., Brinkman, D.L., Kookana, R., Leusch, F.D.L., et al. 2020, Sources, presence and potential effects of contaminants of emerging concern in the marine environments of the Great Barrier Reef and Torres Strait, Australia, Science of the Total Environment 719: 135140.
  • 1478. Smith, J.N., Peel, D. and Kelly, N. 2019, Quantitative assessment of relative ship strike risk to humpback whales (Megaptera novaeangliae) in the Great Barrier Reef World Heritage Area, Murdoch University, Perth.
  • 1479. Popper, A.N. and Hawkins, A.D. 2019, An overview of fish bioacoustics and the impacts of anthropogenic sounds on fishes, Journal of Fish Biology 94(5): 692-713.
  • 1480. Miller, M.E., Motti, C.A., Hamann, M., Kroon, F.J. 2023, Assessment of microplastic bioconcentration, bioaccumulation and biomagnification in a simple coral reef food web, Science of the Total Environment 858: 159615.
  • 1481. Department of Infrastructure Transport Regional Development Communications and the Arts 2023, Maritime Emissions Reduction National Action Plan - Scoping paper for Consultative Group, Australian Government.
  • 1482. Department of Infrastructure Transport Regional Development Communications and the Arts 2024, Charting Australia's Maritime Emissions Reductions, <https://www.infrastructure.gov.au/infrastructure-transport-vehicles/maritime/charting-australias-maritime-emissions-reductions>.
  • 1483. Department of Climate Change Energy the Environment and Water 2022, Quarterly Update of Australia’s National Greenhouse Gas Inventory: June 2022, Commonwealth of Australia.
  • 1484. International Maritime Organization 2023, Annex 15 Resolution MEPC.377(80) (adopted on 7 July 2023) 2023 IMO Strategy on Reduction of GHG Emissions from Ships.
  • 1485. Hoogenboom, M.O., Osipova, L., Nordborg, M., Schlaefer, J.A. and Critchell, K. 2024, 9. Dispersal and environmental impacts of pan-oceanic contaminants, in Oceanographic processes of coral reefs: physical and biological links in the Great Barrier Reef, eds E. Wolanski and M.J. Kingsford, Second edn, CRC Press, Boca Raton, Florida, pp. 143-150.
  • 1486. Batley, G.E., Kidd, L., Angel, B.M., Budd, M. and Simpson, S.L. Assessing the Cumulative Effects of Washwater Discharges from Ships’ Open-Loop Exhaust Gas Cleaning Systems on a Receiving Ecosystem, Available at SSRN 4150592.