Wave at dawn, Spit Bay Photo: E Woehler

The waters surrounding the islands provide important foraging areas for the seabirds and marine mammals that breed or haul out on the islands, but they also comprise a marine ecosystem that is unique and special in itself.

The special qualities of the marine area were recognised in the declaration of the HIMI Marine Reserve in 2002. The Reserve includes the islands, but 64,630 of the 65,000 square kilometres of the Reserve is marine, making the Reserve one of the largest marine protected areas in the world.

A fuller description of the marine component of the HIMI Marine Reserve is given below. The other pages in this section discuss the benthic communities (seabed communities), the fishes and cetaceans (whales, dolphins and porpoises) found in those areas. There is also a general description of the oceanography and ocean fronts of the HIMI region.

The HIMI waters

The marine area of the HIMI Marine Reserve can be broadly classified into five smaller marine areas described as the western, central, southern and north-eastern areas, plus the territorial sea (click here for a diagram of the marine area)

• The territorial sea supports near shore marine species and is a foraging area for many flying birds based on the islands.
• The southern area is likely to be highly productive, with a diverse range of benthic assemblages in depths of 500–1000 m.
• The western area, including Coral Bank, displays diverse assemblages of benthic invertebrates, particularly gorgonian corals and barnacles.
• The central area, including Discovery Bank and portions of the northern and southern plateaux, is habitat for long-lived glass and other erect sponges, and a nursery area for commercial fish species.
• In the north-eastern area, Shell Bank supports a separate stock of mackerel icefish, small aggregations of a variety of other fish species, a diverse echinoderm assemblage and a unique shell-grit habitat different from the surface sediments found elsewhere in the region. This north-eastern area, including areas of the north-eastern plateau, is also an important foraging area for land-based marine predators in the HIMI region.

Collectively these areas contain unique features of the benthic environment surrounding HIMI, representative portions of the different habitat types in the HIMI region, and the near surface waters where land-based marine predators concentrate their local foraging activities.