Box MAR5 National assessment of shallow reefs

The Reef Life Survey, supported by the Australian Government’s National Environmental Science Programme, is using standardised monitoring methodology to provide a national assessment of shallow rocky and coral reef biodiversity (in waters less than 25 metres deep) around Australia’s coasts, and at offshore islands and reef systems (Figure MAR23). The survey gathers information on reef fishes; large mobile invertebrates such as sea urchins, crown-of-thorns starfish, lobsters and abalone; and habitat-forming seaweeds and corals. Results from the Australian surveys are directly comparable with global reef surveys conducted by the same organisation.

Current state of Australia’s shallow reefs

Australia’s shallow reefs are in good condition compared with those in many other countries, but substantial pressures have meant that the condition of many is deteriorating. Large areas of some iconic reefs, such as Ningaloo Reef and the Great Barrier Reef, have suffered from loss of coral habitat and predatory reef fishes because of human and environmental pressures since 2011 (Figure MAR24).

Pressures from recreational and commercial fisheries are particularly important for larger fish species and lobsters (e.g. Frisch et al. 2012, GBRMPA 2014a), whereas ocean warming is having widespread impacts on the composition of communities in temperate zones. The 2011 marine heatwave in Western Australia had a large impact on shallow-water reef biodiversity, with widespread coral bleaching in the North-west Marine Region, and loss of kelp habitats and changing fish communities in the South-west Marine Region (Pearce et al. 2011, Wernberg et al. 2016).

Cyclones and storms have also had substantial impacts on coral communities at Ningaloo Reef and parts of the Great Barrier Reef. Coral structures of the inner Great Barrier Reef have been adversely affected by siltation and nutrification. The impacts of crown-of-thorns starfish populations are variable across coral reefs. Introduced species and heavy metal pollution have had serious impacts on the rocky reefs of the Derwent Estuary in Tasmania and, to a lesser degree, in Port Phillip Bay, Victoria. There are healthy populations of large reef fishes at offshore and remote northern locations (see also Quality of habitats and communities and Species groups).

Marine protected areas (MPAs), fishery regulations, and improved catchment and waste management practices are the main management measures currently in place. Since 2011, more MPAs have been established across Australia’s marine estate, and management plans for these have been implemented, particularly in South Australia (see also Environment protection systems). Management associated with established MPAs is having positive effects in these areas. Improved regulations for many reef fisheries have been enacted. Nutrient inputs to the inshore environment are mostly declining because of sewerage infrastructure upgrades and improved catchment practices, although there have been localised increased loadings of nutrients associated with rapid expansion of fish farms in Tasmania (also see GBRMPA [2014a] for details about the impacts of nutrients on the Great Barrier Reef).

Accelerating deterioration is likely unless regulation of recreational fisheries improves. Storms, cyclones and mass coral bleaching events are less predictable, but increases in intensity (cyclones) and frequency (bleaching) are expected under many climate change scenarios.

How a national assessment can help track reef condition

Survey observations are now providing a comprehensive baseline for accurately assessing the spatial distribution of future trends. Establishment of national trends in changing patterns of inshore marine biodiversity will be facilitated through further roll-out of Reef Life Survey locations and the collection of longer timeseries in these locations.

Evans K, Bax NJ, Smith DC (2016). Marine environment: Box MAR5 National assessment of shallow reefs. In: Australia state of the environment 2016, Australian Government Department of the Environment and Energy, Canberra, https://soe.environment.gov.au/case-study/marine-environment/box-mar5-national-assessment-shallow-reefs, DOI 10.4226/94/58b657ea7c296