Southwest Shelf Transition
From Wikipedia, the free encyclopedia
Southwest Shelf Transition is a marine biogeographic region of Australia. It was referred to as South Western Biotone in Integrated Marine and Coastal Regionalisation of Australia (IMCRA) Version 3.3,[1] and as Southwest IMCRA Transition in the National Marine Bioregionalisation of Australia. Both Southwest IMCRA Transition and Southwest Shelf Transition are used in IMCRA Version 4.0.[2][3]
The region extends along the continental shelf roughly from Perth to Geraldton, Western Australia, and has an area of about 27,000 square kilometres. Depth ranges from zero to nearly 300 metres, with a mean depth of 41 metres. Geomorphically the seabed is almost entirely shelf, but there is a small area of scarp at the northern limits.[4]
The province contains two meso-scale bioregions: Abrolhos Islands, consisting of the marine environment immediately sounding the Houtman Abrolhos, and Central West Coast, comprising the remaining area.[2]
Biologically, it is a highly complex transition zone, with many species from other provinces reaching a limit of their range in this bioregion. In particular, it represents a northern limit of a number of warm temperate species, and the southern limit of a number of sub-tropical and tropical species.
[edit] References
- ^ IMCRA Technical Group. "Interim Marine and Coastal Regionalisation for Australia: an ecosystem-based classification for marine and coastal environments". . Environment Australia, Department of the Environment, Australian Government Retrieved on 2008-02-19.
- ^ a b . "A guide to the Integrated Marine and Coastal Biogeographic Regionalisation of Australia: IMCRA Version 4.0: June 2006". . Department of the Environment and Heritage, Australian Government Retrieved on 2008-02-19.
- ^ IMCRA 4.0 data
- ^ 2005 National Marine Bioregionalisation of Australia. Geoscience Australia. Retrieved on 2008-02-26.
