• Coral Monitoring: Start date 21st April 2015; Duration: 10 weeks
  • Dredging: Start date 29th April 2015; Duration: 9 weeks
  • Dredging Locations: Northern end of Tegako
  • Coral bleaching continues to be below trigger levels (50% bleaching C1-C5 averaged over all corals), though levels are increasing at both northern sites
  • No action is required.

Results since 19 June

The coral watch results for the past 1.5 weeks (19th-29th June) are shown in the latest 5 bars in Figure 1 below. Levels of bleaching at the impact sites, 1 North End and 2 Tegako Jetty, have started to increase. Bleaching remains highest of all sites at 3 Catalina Patch (an average of 14% of colony surfaces showing some form of bleaching) (also a current Control). This level has remained about the same since 22nd May.

Average overall levels of all kinds of bleaching at Impact Sites 1 North End and 2 Tegako Jetty on 29th June was 11.2 and 10.9% respectively. At 4 South End Control, the overall bleaching is around 3%.

Figure 2 shows the change in bleaching level by at least 3 of the coral species at 1 North End and 2 Tegako Jetty impact sites and little change over time at controls, except for Acropora florida at 3 Catalina Patch. This graph shows that the increase in bleaching is likely to be caused by the dredging. However, levels are not yet high enough to trigger management actions.

Figure 1: Average percentage of all coral surfaces in each level of bleaching (C1-5) and unbleached (C6) at each of the 4 sites. At this time Site 1 North End and  Site 2 Tegako Jetty are close to the dredging and considered impact sites. Site 3 and 4 are considered controls.


Figure 2: Levels of bleaching by species and site.