At a glance

Australia’s marine environment is experiencing pressures from a wide range of sources that affect its habitats, communities, species and ecosystem functioning to varying degrees. With many pressures affecting the marine environment and its inhabitants at any one time, it can be difficult to attribute observed impacts to individual pressures. It is particularly difficult to understand or predict how individual pressures will interact and what the cumulative impacts will be.

The overarching pressure that is currently affecting the marine environment—and will continue to affect it even with reduction of greenhouse gas emissions—is climate change. Anthropogenically driven ocean warming, superimposed on natural climate variations, and ocean acidification pose risks to Australia’s coral reef ecosystems, and giant kelp and other habitats, including deep-ocean communities. Sea surface temperatures are continuing to increase nationally, with waters in the South-east and South-west marine regions increasing at a rate of more than 0.4 °C per decade. There is already evidence that, as waters have warmed, some species have shifted their distributions towards the poles, altering marine ecosystems. Changes to nutrient supply and dissolved oxygen are also projected to occur because of climate change; however, observations are insufficient at present to identify whether changes are occurring.

Extraction of resources—such as seafood, and oil and gas—from the marine environment is highly variable in its distribution and impacts. Many pressures associated with the extraction of resources are highly localised, and the likelihood of recovery of affected habitats, communities and species is high once the pressure is removed. Other pressures are more widespread or more persistent, or both, leaving little likelihood of recovery in the short to medium, and even long, term.

Overall, the footprint of pressures within Australian waters associated with commercial fishing has decreased in the past decade. Pressures associated with recreational fishing are generally stable, although, for some species, recreational catches now exceed commercial catches and are increasing. Pressures associated with the oil and gas industries, marine mining and dumping of waste tend to be localised, and are either stable, declining or increasing, but with the prospect that they may decline because of recent legislation.

Use of the marine environment by commercial and recreational vessels continues to increase. The risks associated with such activities that are not currently actively managed (e.g. anchor scour, ship strike, noise) are also increasing. High, but variable, concentrations of marine debris are found in all marine environments, and it is expected that marine debris will continue to be a ubiquitous problem because of continued growth in plastics production and use. As a result, marine debris has been identified as a key threatening process for marine vertebrate species. There is insufficient understanding of the long-term impacts of chronic noise in the marine environment, or trends in toxins, pesticides and herbicides.

Pressures affecting the marine environment are distributed unevenly, resulting from variable uses of the marine environment on local scales, and from broader spatial and temporal variability in climatic and oceanographic processes.

In general, pressures on the marine environment tend to be greater in inshore environments than in offshore environments because these areas are more readily accessible for human use, closer to coastal infrastructure, influenced by coastal and watershed activities to a greater extent, and exposed to inshore oceanographic processes (which tend to be more energetic than those further offshore) (Evans et al. 2016). The shallower water closer to the coasts also exposes species and habitats in these areas to increased environmental variability. This can result in greater capacity to adapt to change. Habitats or species are at greater risk when they have a lower resistance or adaptability to a certain pressure and/or a lower rate of recovery once the pressure is removed. In deeper areas of the ocean, recovery rates may be so slow that it is impossible to distinguish between recovery taking decades or more and a failure to recover within most management timeframes (Williams et al. 2010b).

Because there are many pressures affecting the marine environment and its inhabitants at any one time, it can be difficult to attribute observed impacts to individual pressures. It is particularly difficult to understand or predict how individual pressures will interact and what the cumulative impacts will be.

While recognising that many pressures that manifest in coastal regions influence the marine environment, pressures associated with the land–marine interface or that predominate in the coastal environment (e.g. coastal development, coastal waterway sedimentation and pollution) are not covered in this report. These are covered extensively in the Coasts report. In particular, readers should refer to the Coasts report for detail on pressures associated with pollution in estuary and embayment regions, pollution associated with land-sourced input of nutrients, aquaculture, port developments and tourism.

Of the pressures assessed in 2016, those associated with climate change are having the highest impacts on the marine environment, with the condition of physical (e.g. ocean temperature, currents and eddies) and chemical (e.g. ocean acidification, nutrients) features of the environment assessed as either deteriorating or uncertain. Pressures associated with oil and gas have decreased in the past 5 years, and most pressures associated with resource extraction and use are considered to have low impact, with either stable or unclear trends. Pressures associated with marine debris continue to be high, and related conditions for the marine environment continue to deteriorate.

Evans K, Bax N, Bernal P, Bouchon Corrales M, Cryer M, Försterra G, Gaymer CF, Häussermann V & Rice J (2016). South Pacific Ocean. In: Inniss L, Simcock A, Ajawin AY, Alcala AC, Bernal P, Calumpong HP, Araghi PE, Green SO, Harris P, Kamara OK, Kohata K, Marschoff E, Martin G, Padovani Ferreira B, Park C, Payet RA, Rice J, Rosenberg A, Ruwa R, Tuhumwire JT, Van Gaever S, Wang J & W?s?awski JM (eds), The first global integrated marine assessment: world ocean assessment 1, United Nations, New York.

Topics

Marine environment

Climate and system variability

Climatic variability associated with increased monsoonal activity during the summer months in the tropical north and seasonal cycles in the temperate south leads to variations in water temperature (e.g. Figure MAR4), rainfall pattern
2016
Relates to
Marine environment
Pressures
TasmaniaMarine Temperate EastMarine South WestGreat Barrier ReefMarine North WestMarine South EastIndian Ocean
Marine environment

Climate change

Anthropogenic ocean warming and ocean acidification, superimposed on natural climate variations—in particular, ENSO and decadal variability (Holbrook et al.
2016
Relates to
Marine environment
Pressures
TasmaniaMarine South WestGreat Barrier ReefEast CoastMarine South EastIndian Ocean
Marine environment

Commercial and recreational fishing

Australia’s commercial wild-caught marine fisheries are highly diverse and contribute significantly to the economy.
2016
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Marine environment
Pressures
TasmaniaMarine Temperate EastGreat Barrier ReefMarine South EastIndian Ocean
Marine environment

Traditional use of marine resources

Traditional use of marine resources is defined here as activities (fishing, collecting, hunting and gathering) by the 2 Indigenous or traditional owner groups of Australia: Aboriginal and Torres Strait Islander people.
2016
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Marine environment
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Marine North
Marine environment

Marine oil and gas exploration and production

Australia has large reserves of gas and substantial reserves of oil, with extraction activities producing 79.4 million barrels of crude oil in 2014 (APPEA 2015).
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Marine environment
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Marine Temperate EastMarine South WestMarine NorthMarine North WestMarine South EastMarine Coral Sea
Marine environment

Marine mining and industry

A wide variety of mineral resources exist within Australia’s maritime jurisdiction (Table MAR3). Mining of these resources, however, remains an emerging industry (AIMS 2014).
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Marine environment
Pressures
Marine environment

Marine renewable energy generation

The marine renewable energy industry is an emerging industry globally.
2016
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Marine environment
Pressures
Marine environment

Marine vessel activity

International vessels operating in Australian waters mainly comprise large cargo carriers, but may also include smaller commercial ships, cruise vessels and international yachts.
2016
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Marine environment
Pressures
Great Barrier Reef
Marine environment

Anthropogenic noise

Humans and their activities in the marine environment introduce noise into the ocean in various ways.
2016
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Marine environment
Pressures
Marine Temperate EastMarine South WestGreat Barrier ReefMarine NorthMarine North WestMarine South East
Marine environment

Marine debris

Within the marine environment, marine debris is sourced from both the land (rubbish flushed out to sea; see further detail on coastal pollution in the Coasts report) and marine industries (loss of equipment, often from fishing operat
2016
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Marine environment
Pressures
Marine environment

Toxins, pesticides and herbicides

The group of chemicals typically regarded as pollutants encompasses a large array of compounds, and is generally divided into chemical compounds and metals.
2016
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Marine environment
Pressures
Great Barrier Reef
Marine environment

Dumped wastes

By volume, dredging contributes the largest pressure associated with dumped wastes (not including marine debris, toxins, pesticides and herbicides) on the marine environment.
2016
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Marine environment
Pressures
Marine North West
Marine environment

Additional pressures

Localised, small-scale pressures on the marine environment associated with offshore tourism activities, such as offshore pontoons and cruise vessels (mostly confined to the Great Barrier Reef and the North-west Marine Region), are possibly being exerted on coral reef environm
2016
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Marine environment
Pressures
Great Barrier ReefMarine North West
Evans K, Bax NJ, Smith DC (2016). Marine environment: Pressures. In: Australia state of the environment 2016, Australian Government Department of the Environment and Energy, Canberra, https://soe.environment.gov.au/theme/marine-environment/framework/pressures, DOI 10.4226/94/58b657ea7c296