Intensive Surveys: Trends in cover of benthic organisms

Hard coral cover at Fitzroy Island Reef peaked at 36% in 1997. Bleaching combined with COTS feeding activity and storms caused hard coral cover to drop from 32% in 1999 to 7% in 2000. Coral cover was reduced in all four main hard coral families but the impact was particularly severe for the dominant group, Acroporidae. Bottlebrush Acropora spp. and Montipora spp. declined by 6% and 4% respectively. Hard coral cover showed signs of recovery from 2004 and reached 29% in 2011. This increase reflected increased cover of Porites spp. from 3% in 2000 to 9% by 2007. Within the Acroporidae, foliose Montipora spp had recovered to pre-disturbance levels, whereas bottlebrush Acropora spp. had not. The other major hard coral families have remained below 2% cover since 2000. In 2013, recovery of hard coral cover had stalled and 57 Crown-of-Thorns Starfish were recorded on transects. Coral disease was also moderate in 2013. In 2015 hard coral cover was 17% and Porites was the most abundant hard coral family. The cover of soft corals has fluctuated around 20% throughout the survey period but in 2015 had increased to 29%. Fluctuations in algae cover have mirrored changes in hard coral cover throughout the survey period. In 2015 algae cover was 47% and the community was comprised primarily of turf species. Low level bleaching was observed in 2015 but there were no instances of coral disease. The density of Drupella spp. was 7/ha in 2015.