reefs in the Region was relatively good, but likely to be declining slightly, especially in inshore areas. It was also reported that coral cover has undergone a wide range of changes, including dramatic increases and decreases on different reefs, and that there is no strong, consistent overall trend in the condition of coral reefs across the Great Barrier Reef. However, recent analysis of the long-term dataset shows hard coral cover has significantly declined over the past 30 years (Figure 2.5).18 Since 1986, though there have been some periods of recovery, the overall average hard coral cover in the Region is estimated to have declined from 28 to 13.8 per cent and the rate of decline has increased substantially in recent years18. The decline has been most severe on reefs south of latitude 20 degrees (near Bowen) particularly since 2006. Since that time, hard coral cover has reduced from about 35 per cent to eight per cent in the southern third of the Region. Hard coral cover in the northern area has not shown similar declines and is in better condition.
Figure 2.5 Hard coral cover, 1986–2012
The solid line represents modelled coral cover based on the analysis of data collected from 214 reefs across the Region; while the dashed lines either side represent the associated standard errors. Average hard coral cover in the Region has declined significantly since monitoring began in 1986.18 Declines have been most severe in the south. Source: De’ath et al. 201218