The Northwest Shelf Transition, also known as Bonaparte Coast, is a

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 Australia's

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 island ...

. It adjoins the

Kimberley Kimberly or Kimberley may refer to: Places and historical events Australia * Kimberley (Western Australia) ** Roman Catholic Diocese of Kimberley * Kimberley Warm Springs, Tasmania * Kimberley, Tasmania a small town * County of Kimberley, a ...

region of

Western Australia Western Australia (commonly abbreviated as WA) is a state of Australia occupying the western percent of the land area of Australia excluding external territories. It is bounded by the Indian Ocean to the north and west, the Southern Ocean to th ...

and the adjacent coast of the

Northern Territory The Northern Territory (commonly abbreviated as NT; formally the Northern Territory of Australia) is an states and territories of Australia, Australian territory in the central and central northern regions of Australia. The Northern Territory ...

Geography

The Northwest Shelf Transition includes the coastal waters and continental shelf of northeastern Western Australia and the northwestern Northern Territory, between

Cape Leveque Cape Leveque is at the northernmost tip of the Dampier Peninsula in the Kimberley region of Western Australia. Cape Leveque is (via the Cape Leveque Road) north of Broome, and is remote with few facilities. Nevertheless, the Cape's sandy bea ...

and the

Tiwi Islands The Tiwi Islands ( tiw, Ratuati Irara meaning "two islands") are part of the Northern Territory, Australia, to the north of Darwin adjoining the Timor Sea. They comprise Melville Island, Bathurst Island, and nine smaller uninhabited islands, wi ...

. It has an area of 305,463 km², extending from the shore to 330 metres depth. Most of the region ranges from 10 to 100 metres depth. The

Northwest Shelf Province The Northwest Shelf Province, also known as Exmouth to Broome, is a biogeographic region of Australia's continental shelf. Geography The Northwest Shelf Province includes the coastal waters and continental shelf of north-western Western Australia ...

lies to the west, and the

Northern Shelf Province The Northern Shelf Province, also known as Arnhem Coast to Gulf of Carpentaria, is a biogeographic region of Australia's continental shelf. It includes the coastal waters of Arnhem Land and the Gulf of Carpentaria in Northern Australia. Geogr ...

to the east. The continental slope and deep ocean waters of the

Timor Sea The Timor Sea ( id, Laut Timor, pt, Mar de Timor, tet, Tasi Mane or ) is a relatively shallow sea bounded to the north by the island of Timor, to the east by the Arafura Sea, and to the south by Australia. The sea contains a number of reefs, ...

lie to the north.

Oceanography

The waters are tropical. Surface waters are generally from the

Indonesian Throughflow The Indonesian Throughflow (ITF; ) is an ocean current with importance for global climate as is the low-latitude movement of warm, relative freshwater from the north Indopacific, Pacific to the Indian Ocean. It thus serves as a main upper branch ...

. The shoreline is complex, with rocky headlands, embayments, beaches, estuaries, and offshore islands. The seafloor is also complex, with submerged terraces, carbonate banks, pinnacles, reefs, and sand banks.

Ecology

Sea life is typical of the tropical

Central Indo-Pacific The Central Indo-Pacific is a biogeographic region of Earth's seas, comprising the tropical waters of the western Pacific Ocean, the eastern Indian Ocean, and the connecting seas. The Central Indo-Pacific is a part of the larger Indo-Pacific, w ...

marine realm. Habitats include soft-bottom (sand and mud) and harder (rock) substrates. Coral reefs are uncommon."Carbonate bank and terrace system of the Van Diemen Rise". ''Species Profile and Threats Database'', Department of Agriculture, Water and the Environment, Government of Australia. Accessed 29 July 2021. https://www.environment.gov.au/sprat-public/action/kef/view/33 The carbonate banks and pinnacles of the

Joseph Bonaparte Gulf Joseph Bonaparte Gulf is a large body of water off the coast of the Northern Territory and Western Australia and part of the Timor Sea. It was named after Joseph Bonaparte, brother of Napoleon and King of Naples (1806-1808) and then Spain (1808 ...

form habitats distinct from others in the region, and support high diversity of marine species including

sponge Sponges, the members of the phylum Porifera (; meaning 'pore bearer'), are a basal animal clade as a sister of the diploblasts. They are multicellular organisms that have bodies full of pores and channels allowing water to circulate through t ...

gardens and

octocoral Octocorallia (also known as Alcyonaria) is a class of Anthozoa comprising around 3,000 species of water-based organisms formed of colonial polyps with 8-fold symmetry. It includes the blue coral, soft corals, sea pens, and gorgonians (sea fans ...

s. The carbonate banks are home to

Olive ridley turtle The olive ridley sea turtle (''Lepidochelys olivacea''), also known commonly as the Pacific ridley sea turtle, is a species of turtle in the family Cheloniidae. The species is the second-smallest and most abundant of all sea turtles found in th ...

s, olive sea snake (''Aipysurus laevis'') and turtle-headed sea snake (''Emydocephalus annulatus''), and attract large fish like

mackerel Mackerel is a common name applied to a number of different species of pelagic fish, mostly from the family Scombridae. They are found in both temperate and tropical seas, mostly living along the coast or offshore in the oceanic environment. ...

red snapper Red snapper is a common name of several fish species. It may refer to: * Several species from the genus ''Lutjanus'': ** ''Lutjanus campechanus'', Northern red snapper, commonly referred to as red snapper in the Gulf of Mexico and western Atlanti ...

(''Lutjanus erythropterus''), and goldband snapper (''Pristipomoides multidens''). The Western Australian population of

humpback whale The humpback whale (''Megaptera novaeangliae'') is a species of baleen whale. It is a rorqual (a member of the family Balaenopteridae) and is the only species in the genus ''Megaptera''. Adults range in length from and weigh up to . The hump ...

s (''Megaptera novaeangliae'') mate and give birth in the bays along the Kimberley coast during the winter months, before migrating south along the Western Australian coast to their summer feeding grounds in the

Southern Ocean The Southern Ocean, also known as the Antarctic Ocean, comprises the southernmost waters of the World Ocean, generally taken to be south of 60° S latitude and encircling Antarctica. With a size of , it is regarded as the second-small ...

Meso-scale bioregions

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 (EE ...

(IMCRA) identifies six distinct meso-scale bioregions that make up the province. * Kimberley (KIM) *

King Sound King Sound is a large gulf in northern Western Australia. It expands from the mouth of the Fitzroy River, one of Australia's largest watercourses, and opens to the Indian Ocean. It is about long, and averages about in width. The port town ...

(KSD) * Anson Beagle (ANB) * Cambridge-Bonaparte (CAB) *

Bonaparte Gulf Joseph Bonaparte Gulf is a large body of water off the coast of the Northern Territory and Western Australia and part of the Timor Sea. It was named after Joseph Bonaparte, brother of Napoleon and King of Naples (1806-1808) and then Spain (1808 ...

(BON) * Tiwi (TWI)

References

{{reflist Biogeography of Western Australia Biogeography of the Northern Territory Ecoregions of Australia Marine ecoregions Central Indo-Pacific IMCRA provincial bioregions