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Key departmental publications, e.g. annual reports, budget papers and program guidelines are available in our online archive.

Much of the material listed on these archived web pages has been superseded, or served a particular purpose at a particular time. It may contain references to activities or policies that have no current application. Many archived documents may link to web pages that have moved or no longer exist, or may refer to other documents that are no longer available.

Our Sea, Our Future
Major findings of the State of the Marine Environment Report for Australia

Compiled by Leon P. Zann
Great Barrier Reef Marine Park Authority, Townsville Queensland

Department of the Environment, Sport and Territories, Canberra (1995)
ISBN 0 642 17391 5

1. Description of Australia's marine environment and its status - continued

Marine biodiversity

The ocean is the cradle of life on earth. Of the 33 major animal groups or phyla, 28 are found in the sea. Thirteen of these are exclusively marine(85). Life forms, life histories and ecological processes are very different in the sea than on the land, often necessitating different approaches to marine environmental management (15). The reproductive cycles of marine organisms are often closely linked with water movements and most species have spores or larval stages some of which are dispersed over very great distances. Because of the vagaries of currents and ocean conditions, their populations are subject to considerable year to year fluctuations. Marine species, bathed as they are in water, are particularly susceptible to water-borne pollutants (15).

Biogeography and origins of Australia's marine biodiversity

Australia's coastal sea life, although less well known than our unique land life, is also notable for its high proportion of endemic species (species found only in a particular area). There are two distinct biogeographic regions or provinces in Australia: the temperate south, and the tropical north, which overlap on the western and eastern coastlines.(5)

In the south, which has been geographically and climatically isolated for around 40 million years, about 80-90% of species of most marine groups are endemic, or restricted to this area. IN the north, which is connected by currents to the Indian and Pacific Ocean tropics, only around 10% of most groups are endemic(5)

The number of distinct 'bioregions' in Australian waters has not been agreed upon. A classification for the Council of Conservation Ministers in 1985 produced 32 bioregions (p.81)(86), but this has not been widely recognised.(5) A new classification is currently being developed as a basis for the National Represenative of Marine Protected Areas in the Ocean Rescue 2000 program.

Figure 8 Figure 8

Figure 8: The origin of Australia's coastline and marine life. Australia-Antarctica separated from Gondwana around 100 million years ago and drifted away to the east, carrying coastal fauna and flora with it (a-d). After the split from Antarctica, Australia drifted northwards, colliding with South-east Asia forming Papua New Guinea, linking the two regions' marine life (e-g). As a result, marine life in northern Australia is mainly tropical Indo-pacific in origin. Marine life in the climatically isolated temperate south is ancient Tethyan and Palaeoaustral in origin, and has a very high proportion of endemic species.