Document ID: chunk:federal_register_of_legislation:F2025L00100:front:0:p84
Version: federal_register_of_legislation:F2025L00100
Segment Type: other
Provision Reference: 
Character Range: 259633–262535

bodies of water separated by 2 major oceanographic fronts (boundaries between distinct water masses) which run eastwest through the park.
The Sub-Antarctic Zone, with water temperatures greater than 8°C, is north of the Subantarctic Front. The Polar Frontal Zone, with water temperatures between 5.5°C and 8°C, lies between the 2 fronts. The Antarctic Zone, with water temperatures less than 5.5°C, is south of the
Polar Front. The Subantarctic Front is the transition between calcareous phytoplankton to the north and siliceous phytoplankton to the south. The area between the fronts has high nutrients but low phytoplankton productivity due to limited availability of iron. Macquarie Island and ridge provide a source of iron, so productivity is elevated downstream, to the north-east
of the island.

The park contains habitats, species and ecological communities associated with one provincial bioregion – Macquarie Province. This bioregion is characterised by sub-Antarctic organisms and is very distinct from other bioregions in the south-east region.

The limited sampling and research of the benthic habitats has been focused on Macquarie Ridge and the seamounts. The benthic fauna on the ridge tends to be separated into 3 groups: the northern section (4852°S) is a New Zealand subantarctic fauna, the southern section (5557°S) is an Antarctic fauna, and the central section (5354°S) is a mixed zone with a few endemic species. Along the Macquarie Ridge, the habitat-forming benthic fauna of stony corals and gorgonians mainly occur on the tops of the ridge north and south of Macquarie Island. These areas also have a higher diversity of sponges, crustaceans and echinoderms than areas to the east and west of Macquarie Island. The slopes of the Macquarie Ridge are very steep with rubble fields and tend to have low levels of biodiversity, likely due to their instability. However, overhangs and ledges provide habitats for sponges, gorgonian corals, hydrocorals and anemones. In depths of 200 m to 500 m east and west of Macquarie Island, the fauna is dominated by brachiopods, solitary ascidians and bivalve molluscs. The more sheltered eastern side of the island also has sediment-related fauna, such as sea pens. The bottoms of canyons and troughs are typically sediment dominated, with minimal habitat forming invertebrates.

The peaks of the 5 seamounts surveyed are in depths between about 90 m and 750 m below the sea surface. Each of the seamounts has different faunal assemblages. Fauna on the seamounts include gorgonian corals, bubblegum corals, hydrocorals, stony corals, black corals, sponges, anemones, bryozoans, sea stars, brittle stars, sea cucumbers and crabs.

Based on the limited animal tracking data available at the time of making the plan, several seabird species that breed on Macquarie Island during the summer likely forage in the Macquarie Island Marine Park.