Hard Coral Cover Down By Nearly Half In 18 Years Around Australia's Most Popular Dive Sites

Coral coverage around some of the most popular tourist islands on the Great Barrier Reef has dropped by almost half in the last 18 years, according to a new study. Scientists said they were “shocked” after analysing data from monitoring dives between 1999 and 2017 at 100 different locations across the Whitsunday Islands, Magnetic Island, Keppel Islands and Palm Islands.

The study looked at the coverage of hard corals – the rock-like structures that are the foundations for building reefs – and found they were being hit by multiple impacts, including heat stress causing bleaching, cyclones, flood plumes and poor water quality.

Daniela Ceccarelli, of the ARC Centre of Excellence for Coral Reef Studies at James Cook University, said: “The loss [of hard corals] was between 40 and 50% at each island group. We were pretty shocked actually.” She said that inshore reefs like the ones studied were more susceptible to impacts from sediments and nutrients running off the land, especially reefs that were less exposed to waves that could wash pollution away more quickly.

Published in the Ecological Society of America’s Ecological Applications journal, the study found “persistent shifts from coral to macroalgal dominance” on some reefs in the central and southern parts of the system. The study aimed to tease apart the relative importance of different stressors on inshore island reefs, including the impacts of heat stress, flood plumes and exposure to cyclones.E

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https://www.theguardian.com/environment/2019/oct/25/coral-cover-around-popular-great-barrier-reef-islands-has-almost-halved