The extent and protection of Australia’s deep sea

Abstract

Context. Australia has the third largest exclusive economic zone in the world, but little is known about its deepest parts because, historically, research has focussed on coast regions or in the top 1000 m. Aim. We aim to identify the extent of Australia's deep sea, the deepest locations in Australian waters, and investigate how much of Australia's deep sea is located within marine parks. Methods. We use altimetry-derived water depth to calculate the total area in 1000-m bins. Key results. The total area of Australian waters, excluding Antarctic waters, is 8 914 134 km 2 , of which, 70.4% is deep sea greater than 1000 m and 48% is deeper than the 3000-m abyssal boundary. In total, 56% of Australian Marine Parks are deeper than 3000 m and 20 of 61 marine reserves include water deeper than 5000 m. Conclusions. The Convention on Biological Diversity calls for marine protected areas globally to increase from 7.7 to 30% by 2030: Australia has already placed over 40% of its waters under protection. Despite this, there are no long-term programs monitoring the deep sea and Australia has not produced a globally significant amount of deep-sea science. Implications. Herein lies opportunities for Australia to understand fully its largest habitat and become the global exemplar of deep-sea science and conservation.