Southwest Shelf Transition

[4] The Houtman Abrolhos Archipelago lies about 60 km from the mainland coast, near the edge of the continental shelf.

Each group rests on a shallow undersea carbonate platform that includes extensive coral reefs.

Biologically, it is a highly complex transition zone, with many species from other provinces reaching a limit of their range in this bioregion.

The Houtman Abrolhos is home to the highest concentration of west coast endemic species.

[5] The Integrated Marine and Coastal Regionalisation of Australia (IMCRA) identifies two meso-scale bioregions that make up the transition.