Tweed–Moreton, also known as the Central Eastern Shelf Transition, is a marine

biogeographic Biogeography is the study of the distribution of species and ecosystems in geographic space and through geological time. Organisms and biological communities often vary in a regular fashion along geographic gradients of latitude, elevation, ...

region of eastern

Australia Australia, officially the Commonwealth of Australia, is a country comprising mainland Australia, the mainland of the Australia (continent), Australian continent, the island of Tasmania and list of islands of Australia, numerous smaller isl ...

. The region includes the coastal and estuarine waters from just north of the Baffle Creek estuary in Queensland to north of

Nambucca Heads Nambucca Heads is a town on the Mid North Coast of New South Wales, Australia in the Nambucca Valley. It is located on a ridge, north of the estuary of the Nambucca River near the Pacific Highway. Its population at the was 6,668 (6,314 in t ...

New South Wales New South Wales (commonly abbreviated as NSW) is a States and territories of Australia, state on the Eastern states of Australia, east coast of :Australia. It borders Queensland to the north, Victoria (state), Victoria to the south, and South ...

. It extends from the shore to the edge of the narrow

continental shelf A continental shelf is a portion of a continent that is submerged under an area of relatively shallow water, known as a shelf sea. Much of these shelves were exposed by drops in sea level during glacial periods. The shelf surrounding an islan ...

,Thackway R, Cresswell ID. 1998. Interim Marine and Coastal Regionalisation for Australia: An Ecosystem-based Classification for Marine and Coastal Environments. Version 3.3. Canberra (Australia): Environment Australia, Commonwealth Department of the Environment. with an area of 46,484 km²."Tweed-Moreton". DOPA Explorer. Accessed 8 August 2021
/ref> It is a transition zone between the tropical waters of the northeastern Australian coast (

Northeast Shelf Province The Northeast Shelf Province is a biogeography, biogeographic region of Australia's coastal and continental shelf waters. It includes the tropical coastal waters of the central and southern Great Barrier Reef in northeastern Australia. It is a pro ...

) and the warm temperate seas of the central eastern Australian coast ( Manning-Hawkesbury or Central Eastern Shelf Province). It is defined as both a bioregional province and meso-scale bioregion in the

Integrated Marine and Coastal Regionalisation of Australia The Integrated Marine and Coastal Regionalisation of Australia (IMCRA), formerly the Interim Marine and Coastal Regionalisation for Australia, is a biogeographic regionalisation of the oceanic waters of Australia's exclusive economic zone (EEZ ...

(IMCRA). and as a

marine ecoregion A marine ecoregion is an ecoregion, or ecological region, of the oceans and seas identified and defined based on biogeographic characteristics. Introduction A more complete definition describes them as “Areas of relatively homogeneous species ...

in the Marine Ecoregions of the World system developed by the

World Wide Fund for Nature The World Wide Fund for Nature (WWF) is a Swiss-based international non-governmental organization founded in 1961 that works in the field of wilderness preservation and the reduction of human impact on the environment. It was formerly named th ...

(WWF).Spalding, Mark D., Helen E. Fox, Gerald R. Allen, Nick Davidson ''et al.'' "Marine Ecoregions of the World: A Bioregionalization of Coastal and Shelf Areas". ''Bioscience'' Vol. 57 No. 7, July/August 2007, pp. 573–583

/ref>

Oceanography

Coastal ocean circulation is dominated by the main stream of the

East Australian Current The East Australian Current (EAC) is a warm, southward, western boundary current that is formed from the South Equatorial Current (SEC) crossing the Coral Sea and reaching the eastern coast of Australia. At around 15° S near the Australian co ...

. It runs southwards parallel to the shore, moving tropical

Coral Sea The Coral Sea () is a marginal sea of the Pacific Ocean, South Pacific off the northeast coast of Australia, and classified as an Interim Biogeographic Regionalisation for Australia, interim Australian bioregion. The Coral Sea extends down t ...

waters into the temperate continental shelf waters. Localised centres of

upwelling Upwelling is an physical oceanography, oceanographic phenomenon that involves wind-driven motion of dense, cooler, and usually nutrient-rich water from deep water towards the ocean surface. It replaces the warmer and usually nutrient-depleted sur ...

occur during springtime on a 40-day cycle off

Evans Head Evans Head is a town in Richmond Valley Council of the Northern Rivers region of New South Wales, Australia. At the 2016 census, Evans Head had a population of 2,843 people. It is 726 kilometres north of Sydney, and 11 kilometres east off th ...

(29°17’S). When upwelling is active it increases nutrient levels five- to ten-fold over normal values. The region is characterised by extensive sandy beaches punctuated by rocky headlands. There are extensive coastal estuaries behind sand islands, and offshore barrier islands. Beaches and sediments are generally of terrestrial origin. Tides range from 1 to 3 metres. Typical wave breaker heights are between 1.4 and 3.0 metres. Wave energy generally peaks in July, with a secondary peak during February in the New South Wales (southern) section.

Ecology

Tweed–Moreton is near the southern limit of

hard coral Scleractinia, also called stony corals or hard corals, are marine animals in the phylum Cnidaria that build themselves a hard skeleton. The individual animals are known as polyps and have a cylindrical body crowned by an oral disc in which a mo ...

s, with 60 coral genera in the north and fewer than 50 in the south. Sandstone outcrops form the substrate for reef faunas. These include the offshore

Flinders Reef Flinders Reef is a small isolated reef near Moreton Island, north-east of Cape Moreton in South East Queensland, Australia. It has the highest number of coral species of any subtropical reef system along Australia's east coast and is the neares ...

and fringing reefs at

Hervey Bay Hervey Bay () is a city on the coast of the Fraser Coast Region of Queensland, Australia. The city is situated approximately or 3½ hours' highway drive north of the state capital, Brisbane. It is located on the bay of the same name open to ...

. The New South Wales portion has two distinctive species assemblages of temperate reef fishes,

echinoderm An echinoderm () is any animal of the phylum Echinodermata (), which includes starfish, brittle stars, sea urchins, sand dollars and sea cucumbers, as well as the sessile sea lilies or "stone lilies". While bilaterally symmetrical as ...

s, and gastropods, and a single distinctive species assemblage of

hermatypic coral Hermatypic corals are those corals in the order Scleractinia which build reefs by depositing hard calcareous material for their skeletons, forming the stony framework of the reef. Corals that do not contribute to coral reef development are referred ...

s and

bivalve Bivalvia () or bivalves, in previous centuries referred to as the Lamellibranchiata and Pelecypoda, is a class (biology), class of aquatic animal, aquatic molluscs (marine and freshwater) that have laterally compressed soft bodies enclosed b ...

s. The region has a distinctive assemblage of algal species. There is a significant difference in occurrences of seagrass species from north to south along the coast. The offshore benthic fauna is not well known. Low closed to open mangrove forest communities are found along sheltered coasts and rivers. There are eight mangrove tree species and three mangrove understorey species in the Queensland portion, along with 14 species of saltmarsh plants. Mangrove development and species diversity is lower in the New South Wales portion.

Protected areas

Protected marine areas include

Great Sandy Biosphere Reserve Great Sandy Biosphere Reserve is a biosphere reserve in the Australian state of Queensland located on land and coastal waters associated both with the local government areas of the Fraser Coast Region and the Gympie Region and Fraser Island (also ...

Moreton Bay Marine Park The Moreton Bay Marine Park was established in 1993 to protect ecologically significant habitats in Moreton Bay. The marine park extends from Caloundra south to the southern tip of South Stradbroke Island. The marine park's border extends up to t ...

Cape Byron Marine Park Cape Byron Marine Park is one of four marine parks in New South Wales, Australia, and is the most recently sanctioned.Marine Parks Authority. 2003. Background resource working paper for the Cape Byron Marine Park. Marine Parks Authority, Sydney. ...

, Richmond River Nature Reserve, and

Solitary Islands Marine Park Solitary Islands Marine Park (SIMP) is a marine park in New South Wales State waters, Australia. It adjoins the Solitary Islands Marine Reserve (Commonwealth Waters) and was declared under the ''Marine Parks Act 1997 New South Wales, (NSW)'' ...

References

{{DEFAULTSORT:Tweed-Moreton Marine ecoregions Ecoregions of Australia IMCRA meso-scale bioregions Temperate Australasia IMCRA provincial bioregions Biogeography of New South Wales Biogeography of Queensland