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). As of 2008, the most recent version is IMCRA Version 4.0.[1] [2]
IMCRA actually defines two bioregionalisations: a benthic bioregionalisation, based on biogeography of fish together with geophysical data; and a pelagic bioregionalisation, base on oceanographic characteristics.[2]
The benthic bioregionalisation incorporates three separate regionalisations:[2]
The pelagic bioregionalisation divides the continental shelf into four provincial bioregions based on pelagic fish species biodiversity and richness. Offshore waters are divided into three-dimensional water masses, taking into account water properties, circulation patterns and energetics.[2]
This is a list of IMCRA 4.0 provincial bioregions:[3]
| Bioregion | information | IMCRA meso-scale bioregions | Marine Ecoregions of the World designation | |
|---|---|---|---|---|
| cold temperate waters | Central Victoria (CV) Victoria Embayment (VE), Central Bass Strait (CBS), Boags (BGS) | Bassian (205) | ||
| Cape Province | na | na | ||
| warm temperate waters | Manning Shelf (MAN), Hawkesbury Shelf (HAW) | Manning-Hawkesbury (203) | ||
| transition between the tropical Northeast Shelf and warm-temperate Central Eastern Shelf provinces | Tweed-Moreton (TM) | Tweed-Moreton (202) | ||
| Central Eastern Province | na | na | ||
| Central Eastern Transition | na | na | ||
| subtropical waters | Shark Bay (SBY), Zuytdorp (ZUY) | Shark Bay (210) | ||
| transition | Ningaloo (NIN) | Ningaloo (145) | ||
| Central Western Province | subtropical waters | na | na | |
| Central Western Transition | na | na | ||
| Christmas Island Province | tropical waters | Cocos-Keeling/Christmas Island (120) | ||
| Cocos (Keeling) Island Province | tropical waters | Cocos-Keeling/Christmas Island (120) | ||
| transition between the warm-temperate Southwest Shelf and Spencer Gulf Shelf provinces | Eucla (EUC), Murat (MUR) | Great Australian Bight (208) | ||
| Kenn Province | tropical waters | na | na | |
| Kenn Transition | ||||
| Lord Howe Province | warm temperate waters | Lord Howe and Norfolk Islands (151) | ||
| Macquarie Island Province | cold temperate waters | Macquarie Island (212) | ||
| Norfolk Island Province | warm temperate waters | Lord Howe and Norfolk Islands (151) | ||
| tropical waters | West Tropic Coast (WTC), Central Reef (CR), Lucinda-Mackay Coast (LMC), Shoalwater Coast (SC), Mackay-Capricorn (MC), Pompey-Swains (PS) | Central and Southern Great Barrier Reef (143) | ||
| transition between the tropical Northern Shelf and Northeast Shelf provinces | Torres Strait (TS), East Cape York (ECY), Ribbons (RBN) | Torres Strait and Northern Great Barrier Reef (142) | ||
| Northeast Province | tropical waters | na | na | |
| Northeast Transition | na | na | ||
| tropical waters | Van Diemens Gulf (VDG), Cobourg (COB), Arafura (ARA), Arnhem Wessel (AWS), Carpentaria (CAR), Groote (GRO), Pellew (PEL), Wellesley (WLY), Karumba-Nassau (KAN), West Cape York (WCY) | Arnhem Coast to Gulf of Carpentaria (140) | ||
| Northwest Province | tropical waters | na | na | |
| tropical waters | Pilbara (nearshore) (PIN), Pilbara (offshore) (PIO), Eighty Mile Beach (EMB), Canning (CAN), North West Shelf (NWS) | Exmouth to Broome (144) | ||
| transition between the tropical Northern Shelf and Northwest Shelf provinces | Kimberley (KIM), King Sound (KSD), Anson Beagle (ANB), Cambridge-Bonaparte (CAB), Bonaparte Gulf (BON), Tiwi (TWI) | Bonaparte Coast (141) | ||
| Northwest Transition | na | na | ||
| transition between the warm-temperate Central Eastern Shelf and the cold-temperate Bass Strait Shelf provinces | Batemans Shelf (BAT), Flinders (FLI), Twofold Shelf (TWO) | Cape Howe (204) | ||
| Southeast Transition | na | na | ||
| Southern Province | warm temperate waters | na | na | |
| warm temperate waters | Leeuwin–Naturaliste (LNE), Western Australia South Coast (WSC) | Leeuwin (209) | ||
| Southwest Shelf Transition | transition between the subtropical Central West Province and the warm temperate Southwest Shelf Province | Abrolhos Islands (ABR) and Central West Coast (CWC) | Houtman (211) | |
| Southwest Transition | na | na | ||
| warm temperate waters | Coorong (COR), Eyre (EYR), North Spencer Gulf (NSG), St Vincent Gulf (SVG), Spencer Gulf (SG) | South Australian Gulfs (207) | ||
| Tasmania Province | cold temperate waters | na | na | |
| cold temperate waters | Bruny (BRU), Davey (DAV), Franklin (FRA), Freycinet (FRT) | Bassian (205) | ||
| Timor Province | tropical waters | na | na | |
| Timor Transition | na | na | ||
| West Tasmania Transition | na | na | ||
| transition between the cold-temperate Bass Strait Shelf and Tasmanian Shelf provinces and the warm-temperate Spencer Gulf Shelf Province | Otway (OTW) | Western Bassian (206) |
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There are 1,334 separate geomorphic units in Australia’s waters, in 14 categories. The regions represent distinct areas of geomorphic features that have similar characteristics (e.g. areas of the continental slope that contain canyons, or flat plains).[2]
Geomorphic features are determined by bathymetric models (depth analysis) of the ocean floor and provide an important predictor of species assemblages at a large scale. For example, different species will occur on low-gradient terraces compared to those on the steep-walled submarine canyons.[4]
Nomenclature of geomorphic features are based on definitions endorsed by the International Hydrographic Organization (IHO, 2001).[5]