Marine vessel activity

2016

International vessels

International vessels operating in Australian waters mainly comprise large cargo carriers, but may also include smaller commercial ships, cruise vessels and international yachts. As an island, Australia relies heavily on commercial vessels for transportation of its imports and exports. In 2013–14, 1425 million tonnes of cargo moved across Australian wharves, 1221.8 million tonnes of which were international exports and imports. A total of 5499 vessels made 28,714 port calls in 2013–14 (BITRE 2015). International exports comprised 85.7 per cent of this cargo, whereas international imports represented 7 per cent. In addition, there were 670 cruise ship visits.

Very few places in the Australian marine environment are not used by marine vessels (Figure MAR16). Major routes used by vessels traverse a wide variety of habitats and ecosystems, and groundings by vessels and accidents at sea in ecologically sensitive areas impose pressures on the marine environment. Since 2011, 4 ships have been reported as grounded, all within embayment or port areas, and 3 vessels have been involved in collision, capsizing or foundering events.5 Vessels also interact directly with marine animals via vessel strike (see Box MAR3) and emit constant noise into the ocean (see Anthropogenic noise). Vessels are a source of atmospheric emissions, including carbon dioxide, nitrous oxide and sulfur. Anchoring in offshore areas can cause sea-floor abrasion and damage to benthic ecosystems (Davis et al. 2016). The exchange of ballast water in nearshore port or mooring environments and biofouling of vessels can introduce foreign marine species to the Australian environment. Biocides used in antifouling paints are toxic when released to the marine environment, and can affect marine species’ growth and reproduction, mainly when the coating is dislodged from the hull or through the coating dissolution process in confined inshore waters (see Thomas & Brooks 2010).

The National Plan for Maritime Environmental Emergencies (NESMG 2014) sets out the cooperative arrangements between government and industry to respond to maritime incidents affecting the environment (see also Effectiveness of marine management).

Domestic vessels

Domestic vessels provide important transport linkages between regional Australia and the cities, and smaller vessels provide an important recreational pastime for many Australians—for example, nearshore use of power vessels (e.g. jetskis, powerboats, cruisers) and yachts, and offshore use of powerboats and yachts. Coastal freight comprised 104.3 million tonnes in 2013–14, representing 7.3 per cent of all cargo moving across Australian ports (BITRE 2015). Pressures associated with coastal freight activities are similar to those associated with international vessels (e.g. groundings, introduction of foreign species), whereas high inshore use by recreational vessels adds considerable risk of disturbance and vessel strike of inshore marine animals such as dolphins, dugongs and marine turtles. Anchoring and mooring of vessels (which are largely unmanaged) have direct impacts on seabed habitats and communities (Davis et al. 2014, 2016)

Propeller marks on the dorsal surface of an Australian snubfin dolphin (Orcaella heinsohni) and scarring on the dorsal fin, indicating interactions with recreational vessels and fishing line

Propeller marks on the dorsal surface of an Australian snubfin dolphin (Orcaella heinsohni) and scarring on the dorsal fin, indicating interactions with recreational vessels and fishing line

Propeller marks on the dorsal surface of an Australian snubfin dolphin (Orcaella heinsohni) and scarring on the dorsal fin, indicating interactions with recreational vessels and fishing lin

Information about incidents such as groundings, collisions and sinking of domestic vessels is reported to either state or territory marine safety agencies, or the Australian Maritime Safety Authority.

Although reporting associated with commercial vessel activities allows the quantification of pressures associated with some activities (e.g. groundings), other pressures (e.g. noise, ship strike) lack reporting mechanisms, and, as a result, impacts are largely unquantified. How increases in vessel activity might be affecting the marine environment is not entirely clear.

Pressures associated with port facilities and infrastructure are described in the Coasts report.

Box MAR3 Vessel strike

Australia relies heavily on commercial vessels for transportation of its imports and exports, with 99 per cent of Australian trade by volume carried by sea (AMSA 2016). With 85 per cent of the population living within 100 kilometres of the coast, recreational boating is a popular pastime for many Australians. There are very few areas in the Australian marine environment where international and domestic vessel activity does not occur (Figure MAR16).

In association with vessel activities, there is a risk of environmental damage from collision or grounding of vessels (NESMG 2014), and harm to marine animals by vessel strike from all types of vessels. Large, high-speed commercial vessels cause the death of whales worldwide (Jensen et al. 2004), and small recreational vessels regularly injure inshore species such as dugongs (Dugong dugon), turtles and dolphins (e.g. Thiele 2010).

Globally, commercial vessel activity has been increasing (Davis et al. 2016). Within Australian waters, commercial vessel activity has grown by approximately 4 per cent each year since the early 2000s (DIRD 2014, BITRE 2015; Figure MAR17). Much of this growth is within significant areas of marine mammal migration and/or breeding, such as the Great Barrier Reef. Use of port areas in regions used by turtles and dugongs is also increasing (e.g. Gladstone Harbour). At the same time, the size of recreational vessels has been increasing across most regions, and activity in remote areas is also increasing (Lyle et al. 2014, Giri & Hall 2015, Ryan et al. 2015, West et al. 2016).

Recently, vessel strike incidents by commercial vessels in Australian waters have predominantly involved humpback whales (Megaptera novaeangliae). Based on the behaviour and distribution of animals, the distribution of high-density commercial vessels, and overlaps between the two, mother–calf pairs of humpback whales have the potential to be particularly susceptible. Incidents with southern right whales (Eubalaena australis), sperm whales (Physeter macrocephalus) and pygmy blue whales (Balaenoptera musculus brevicauda) have also been reported.a Given the speed and size of modern commercial vessels, collisions with whales have a high probability of being fatal (Vanderlaan & Taggart 2007). Vessel strike, particularly by recreational vessels, was identified more than a decade ago as being an issue for marine turtles in Queensland waters, mainly around Moreton Bay and Hervey Bay (EA 2003).

Quantification of historical impacts of vessel strike on marine animals is difficult, because the collation of records (from live, deceased and stranded animals) of vessel strike has not been consistent over time. It is also difficult to ascertain the specific contribution of vessels of varying sizes and types to the problem, because collisions of many animals, particularly with large vessels, will most likely go unnoticed and are therefore not reported (Laist et al. 2001). For example, in Australia, 109 incidents of vessel strike of whales have been reported through official reporting avenues since 1840 (DoEE 2016). However, in some regions, up to 10 per cent of all resident dolphins have been recorded as demonstrating evidence of vessel strike. The low number of official records of vessel strike from these regions suggests that most incidents of vessel strike remain unreported (Thiele 2010). As a result, the impacts of vessel strike on populations of marine animals remain unknown.

Management measures addressing vessel strike

The International Maritime Organization has adopted measures—including precautionary areas, areas to be avoided, re-routing measures and speed restrictions—aimed at minimising vessel strike of whales (Silber et al. 2012). In Australian waters, not enough is known about the spatial or temporal distribution of vessel strike risk or the scale of the issue to implement targeted management measures. Thus, no management frameworks directly addressing vessel strike are in place. However, zoning plans in a number of areas (e.g. Moreton Bay Marine Park) restrict the speed of vessels in an effort to minimise vessel strike of marine animals.

A national vessel strike strategy is being developed by the Australian Government Department of the Environment and Energy (DoEE 2016). The objectives of the strategy are to:

  • collect data to understand the scale of vessel strike
  • undertake risk assessment and analysis of existing databases
  • develop efficient reporting procedures that can be assessed
  • develop mitigation measures
  • engage with industry regarding information gathering and mitigation.

At the same time, the National Environmental Science Programme Marine Biodiversity Hub is developing approaches to identify areas where there is overlap between the density of vessel activity and marine animal aggregation, as a potential indicator of risk of vessel strike. Such information will be essential for the development of risk management strategies focused on vessel strike.

Outlook

Commercial vessel activity is projected to continue to increase (DIRD 2014). Many populations of animals that are likely to interact with vessels are protected, with some recovering from past exploitation. Some, such as humpback whales, have increased notably (Noad et al. 2011). The combined growth of vessel activity and continuing recovery of populations of protected species such as whales are likely to increase the number of interactions between vessels and these populations. The impacts on marine animal populations associated with increased interactions will remain unquantified without effective reporting and mitigation schemes.

a Australian Transport Safety Bureau marine safety investigations and reports and Australian Marine Mammal Centre National Marine Mammal Database

Evans K, Bax NJ, Smith DC (2016). Marine environment: Marine vessel activity. In: Australia state of the environment 2016, Australian Government Department of the Environment and Energy, Canberra, https://soe.environment.gov.au/theme/marine-environment/topic/2016/marine-vessel-activity, DOI 10.4226/94/58b657ea7c296