(Note: A detailed description of the characteristics of the maritime traffic,
the transport of harmful substances, and the threats from maritime incidents, including
a description of the hydrographical, meteorological and oceanographical conditions may
be found in paragraphs 81 to 109 of document MEPC 68/10/1.)
1 Vessel traffic characteristics
Operational factors
1.1 There are two major shipping routes in the region – the Inner Route and
the Outer Route of the GBR. While the Inner Route lies relatively close to the
Queensland coast within the GBR and Torres Strait PSSA, the Outer Route begins at the
north-eastern limit of the Torres Strait (the Great North-East Channel), continues
southwards through the Coral Sea and re-joins the Queensland coast near Sandy Cape
(south of Gladstone) (see figure 1 of appendix 3 of document MEPC 68/10/1).
1.2 The Outer Route experiences south-east trade winds and heavy seas for
about nine months of the year. A vessel suffering serious propulsion or power failure in
the Coral Sea will be many hundreds of kilometres from towage assistance and could drift
on to one of the numerous reefs or cays in the Coral Sea before any towage assistance
can arrive. Anchoring is impractical due to the precipitous depths that prevail up to
the edges of these reefs.
Vessel types
1.3 There is a wide variety of vessel types operating in this area. Ships
entering and leaving Queensland coastal ports are primarily dry bulk carriers (most
notably carrying coal) and, increasingly, liquefied natural gas (LNG) tankers. Oil and
chemical carriers calling at Australian east coast ports mainly choose to use the Outer
Route. Other ships transiting through the south west Coral Sea trading between Asia and
other east coast Australian ports, such as Brisbane, Newcastle, Sydney and Melbourne,
transport a variety of cargoes including containerized, dry, liquid, vehicular and
general cargoes.
Traffic characteristics
1.4 In addition to ships using the Outer Route to transit between Torres
Strait and east coast Australian ports, the Outer Route converges in the south western
Coral Sea with the north/south route used by ships transiting between Asian ports via
Jomard Entrance (Papua New Guinea) and major Australian east coast ports such as
Newcastle, Sydney and Melbourne, and commodity exporting ports in Queensland.
1.5 Ships bound to and from Queensland ports are also a major consideration
in terms of the risk to the ecosystem from international shipping activities in the
south west Coral Sea. There are four main passages through the GBR that result in a
corresponding concentration of traffic in the south west Coral Sea. These are Grafton
Passage (near Cairns); Palm Passage (near Townsville); Hydrographers Passage (near
Mackay); and through the Capricorn and Curtis Channels in the south.
1.6 These shipping routes and passages can be identified in the Automatic Identification
System (AIS) vessel traffic density information provided in appendix 2 of document MEPC
68/10/1.
1.7 Shipping activity in the Coral Sea is expected to increase in the coming years. The
expansion of the Australian resources sector, which includes other east coast bulk ports
such as Newcastle and Port Kembla (most ships en route to and from these ports use the
north/south route through the south west Coral Sea), is the major factor in the expected
growth of 81% in the total national traffic at sea by 2020.
Harmful substances carried
1.8 A wide variety of vessels carrying a range of potentially harmful substances operate
in this area. The Outer Route is generally used by oil and chemical tankers visiting
Australian east coast ports, while there is increasing LNG tanker traffic entering and
leaving Queensland ports.
2 Natural factors
Hydrographical
2.1 There are some areas immediately around Coral Sea cays, reefs and islets where the
depth of water, surveyed bathymetry quality and/or final charted product scale pose some
navigational risk for larger vessel types. These areas are clearly marked on nautical
charts and, in general, such areas should be well avoided by commercial shipping.
Shipping should always navigate with due regard for charted data, chart scale and stated
reliability of data within the area of interest.
2.2 Generally, all areas within the PSSA (apart from the proposed area to be avoided
(ATBA), discussed below) are too deep to offer any anchoring opportunity.
Meteorological
2.3 Parts of the area are subject to the highest frequency of tropical cyclones in
eastern Australia, creating a high disturbance regime for its ecological communities,
resulting in increased diversity due to the frequent regeneration of reefs following
storm events. In the last 100 years, cyclones have become less frequent but more
intense, and in the last 12 years the region has experienced four extreme cyclones
(category 4 or 5).
2.4 In general, during winter months, the predominant winds are from the south-east with
small southerly and easterly components. Summer months exhibit an increased easterly
component in addition to the south easterly winds.
2.5 Winds in these areas may produce shallow surface currents in addition to those deeper
currents described below.
Oceanographic
2.6 Oceanographic processes play a significant role in the biological patterns across the
Coral Sea region. There are three main currents that affect the region; the South
Equatorial, Hiri, and East Australian currents. The South Equatorial Current moves west
toward Townsville and Cairns from offshore waters to the east. As it moves toward the
coast it splits into the north-flowing Hiri Current and the East Australian Current.
Geomorphic features interact with these ocean currents to create variable speeds and
directions.
2.7 A slow and deep (>100 m) clockwise eddy, originating from the East Australian
Current, circulates around the Marion Plateau. A similar gyre system of ocean currents
exists atop the Queensland Plateau. The flow of these localized features is thought to
create a barrier to larval dispersal that contributes to the high species endemism and
localized distribution of species in the region.
2.8 The geomorphic characteristics of the coral reefs and cays reflect the constant
exposure to high energy wind and wave conditions. The East Australian Current and its
associated eddy fields are large scale, spatially predictable, ecologically important
pelagic features represented in the region.
Other information
2.9 The Coral Sea's ecology is largely shaped by physical forces such as climate and
weather patterns, the direction and strength of currents, the shape of the underlying
seabed, and the interaction between water movement and seafloor topography. These forces
affect the distribution of species, the availability of nutrients and prey, the levels
of disturbance experienced by ecological communities and their ability to recover from
natural and human pressures and impacts.
2.10 In addition to the shipwrecks mentioned in annex 2, there have also been a number of
incidents and near misses in the region in recent years that demonstrate the potential
risk of environmental harm by ships that conduct their passage through the waters of the
PSSA extension. Several case studies on near misses in recent years are provided in
appendix 3 of document MEPC 68/10/1.