Marine Bioregional Planning in the North-west
The area
The North-west Marine Region encompasses Commonwealth waters between the Western Australian/Northern Territory border to Kalbarri, south of Shark Bay, an area of some 1.07 million square kilometres.
Source: Department of the Environment, Water, Heritage and the Arts
Bioregions
To assist in the development of Marine Bioregional Planning in Australia, our oceans have been divided into 41 provincial bioregions. Provincial bioregions are large biogeographical areas defined by similar ecological characteristics. The North-west Marine Region includes 8 provincial bioregional units under the Integrated Coastal and Marine Regionalisation of Australia (IMCRAv.4).
Source: Department of the Environment, Water, Heritage and the Arts
Ecological features
A unique combination of biophysical features and ecological processes differentiates the North-west Marine Region from other marine regions around Australia, specifically:
- The Region is comprised of relatively shallow waters with more than 50% of its waters shallower than 500m depth. This is reflective of the Region's large areas of continental shelf and slope which incorporate a number of plateaux (e.g. Scott and Exmouth), terraces (e.g. Rowley and Canarvon), reefs (e.g Ashmore, Scott and the Rowley Shoals) and submerged canyons (e.g. Cape Range and Cloates canyons).
- The Region's oceanography is complex. The Indonesian Throughflow is a dominant influence in the majority of the Region, with the Leeuwin Current dominant in the south. Both these currents are significant drivers of the Region's ecosystems. The fact that both of these surface currents flow pole-ward is globally unique for the western boundaries of ocean basins. The currents are driven by pressure differences between the equator, where the source waters for the currents originate, and the higher density, cooler and more saline waters of the Southern Ocean. The currents are strongly influenced by seasonal change and El Nio and La Nia episodes.
- The Region's waters are predominantly warm tropical waters, with low salinity and are generally nutrient poor. As such, the Region is considered to have a generally low level of productivity. However, there are sporadic bursts of higher productivity in parts of the Region, which are thought to be associated with specific events. For example, seasonal changes in the strength and direction of surface flows create conditions that allow upwelling of nutrients from deeper waters. Upwelling is also thought to be influenced by the interaction of tides with seafloor features, such as submerged canyons and the shelf break, as well as episodic events such as cyclones. These relationships are poorly understood.
- Despite overall low levels of productivity, the Region supports a high biodiversity of tropical marine species predominantly of Indo-Pacific origin and distribution, due to the influence of the Indonesian Throughflow. However, the Region has a low level of endemicity when compared to most other Australian waters, particularly those of the south.
- There are 149 species listed under the EPBC Act that occur within the Region. The Region contains internationally significant breeding and feeding grounds for a number of threatened and migratory marine animals, including whale sharks, humpback whales, turtles, dugong and migratory seabirds. Thousands of humpback whales migrate through the Region each year and it is the only known breeding ground for the Western Australian population of humpbacks. In addition, the Region hosts an annual aggregation of whale sharks around Ningaloo Reef, which is the largest known anywhere in the world.
Marine Protected Areas in the North-west
A key outcome of marine bioregional planning will be the identification of marine protected areas (MPAs) as part of the National Representative System of MPAs. There are four existing MPAs in the North-west Marine Region:
| Name of reserve | Date Declared | Area km2 |
|---|---|---|
| Ningaloo Marine Park (Commonwealth waters) | 1987 | 5,076 |
| Mermaid Reef Marine National Nature Reserve | 1991 | 5.4 | Ashmore Reef National Nature Reserve | 1983 | 583 | Cartier Island Marine Reserve | 2000 | 167 |
The process for identifying additional MPAs in the North-west Marine Region is outlined in more detail in the North-west Bioregional Profile as goals and principles for the development of the regional MPA network. Specific proposals for new MPAs will be developed during the subsequent planning stages and will be informed by consultation with stakeholders. Draft proposals for a network of MPAs, along with analysis of the social and economic impact of all proposals, will be published in the Draft Plan and then be subject to formal consultation and more detailed socio-economic analysis.
Development of the North-west Marine Bioregional Plan
Marine bioregional planning involves three key phases:
- Development of a Bioregional Profile identifying the important ecological, conservation and socio-economic values of the region;
- A draft Marine Bioregional Plan which will outline the draft conservation priorities the Government has identified and include a candidate network of Marine Protected Areas for the region; and
- A final Marine Bioregional Plan containing the Government's conservation priorities for the region, measures to progress them and a final network of MPAs.
The North-west Bioregional Profile was released in October 2008. The draft North-west Marine Bioregional Plan is scheduled for release in October/November 2009. The Department is committed to targeted and effective stakeholder consultation throughout the planning process.
- For more information on the process for developing the North-west Marine Bioregional Plan please refer to updates published on this website and to the North-west Marine Bioregional Plan brochure.
See also
Key
Links to another web site
Opens a pop-up window