Australia (GBR) - Central (Whitsundays / Townsville / Cairns)

The Great Barrier Reef stretches for well over 2,000 km along Australia's northeastern coast, from the Torres Strait's Warrior Reefs to the Capricorn-Bunker group, and Spalding et al. (2001) describe it as a complex system of nearly 3,000 reefs and shoals plus high islands with their own fringing reefs. The same account credits Captain James Cook as the first to navigate these waters, running aground there in 1770. The central section, from Mossman south to the barrier off the Whitsunday and Lindeman Islands, sits on a gradually widening shelf where most reef growth is confined to the outer third, and nearshore waters swing in turbidity and salinity when rivers flood. Its reefs are geologically younger than the northern ones, with smaller reef flats, few cays, and a looser barrier set back from the shelf edge, while the Palm, Whitsunday, and Lindeman island groups carry important fringing reefs. Spalding et al. (2001) give Australia about 48,960 km² of reef nationally; Souter et al. (2021) give 35,487 km² for the GCRMN subregion formed by the Torres Strait–northern GBR, central–southern GBR, and Tweed–Moreton ecoregions. The first recorded mass outbreak of crown-of-thorns starfish was seen at Green Island, off Cairns, in 1962, and most outbreaks since have been in the central sections. In 1998, bleaching was also worst in the central GBR, where about a quarter of inner-shelf reefs showed 60% or more of corals bleached, though mortality was generally low (Spalding et al. 2001).

Souter et al. (2021) trace a run of heavier disturbances after 2000. The 2002 bleaching, like that of 1998, affected about half of the GBR's reefs, with the central section again hardest hit, and after the back-to-back bleaching of 2016 and 2017 the central third, also under attack from crown-of-thorns starfish, lost more than 30% of its coral. A fourth starfish outbreak started in the Cairns–Cooktown section in 2010 and moved south. Severe cyclones added to the losses: Hamish (2009) affected more than half of the GBR's reefs, Yasi (2011) damaged about 15%, mostly between Cairns and Townsville, and Debbie (2017) cut cover by up to 97% on some Whitsunday reefs. Agricultural sediments, nutrients, and pesticides remain problems for inshore reefs. Average GBR coral cover dropped from about 34% in the late 1990s to 24% in 2018.

This summary covers nine sites from the central Great Barrier Reef: seven Whitsunday Islands bays and points, a Whitsundays area marker, and Davies Reef off Townsville. Most of the Whitsunday sites are fringing reefs in north-facing bays on Hook, Hayman, and Border Islands; Pinnacle Point, at Hook Island's northeastern corner, is an exposed point. The exception is Hill Inlet at Whitehaven Beach, a tidal sand and seagrass system rather than a coral reef. Davies Reef is a mid-shelf platform reef and one of the longest-running monitoring reefs in the AIMS program.

First-hand records are thin. None of these sites has photographs or transect data, and only three logged dives, all from early 2007, are on record. At Luncheon Bay, Anderson reached 20.1 m and noted "murky but high coral cover." He dived at Hayman Island twice on 1 February 2007 (his log does not name the bay), noting "great coral canyons" at 16.8 m on the first dive and murky water on the second.

Everything known about reef condition comes from other organizations' surveys, and those surveys show large swings over time. Within 2 km of Butterfly Bay, six Reef Check surveys from 2018 to 2023 ranged from 13% to 32% hard coral. At Cateran Bay, 98 surveys from 1994 to 2023 ranged from 6.5% to 42%, and at Davies Reef 26 surveys from 1993 to 2023 ranged from 10% to 53%. That is a pattern of repeated decline and recovery rather than a steady slide. Severe Tropical Cyclone Debbie crossed directly over the Whitsundays in March 2017, so every Whitsunday survey since then describes reefs after that storm.