SYDNEY, July 26 (Xinhua) -- A major marine heatwave that hit Australia's Great Barrier Reef affected not just its coral but also the fish and other fauna of the region, an impact that sheds new light on the importance of reef communities in one of the world's most valuable ecosystems and their role in coral recovery, according to latest Australian research.
"After reviewing surveys of corals, seaweed, fishes and mobile invertebrates such as sea urchins at 186 sites across the Great Barrier Reef and western Coral Sea before and after the 2016 heatwave we realized that coral bleaching was only part of the story," researcher Rick Stuart-Smith, who led the study under the Institute for Marine and Antarctic Studies, said in a statement on Thursday.
"Changes were also happening around the bleached corals, to the fishes and other animals that the reefs support, and which in turn assist coral recovery."
Australia's iconic reef ecosystem, the largest of its kind, was severely damaged by a mass bleaching event in 2016. Coral bleaching occurs when the reef colonies lose their vivid color in waters that are too warm for the microscopic algae living in them. The bleached corals are physiologically damaged and sustained bleaching will lead to coral death.
The latest study showed how herbivorous fishes such as parrotfish, which play an important "functional" role in preventing algae from taking over and displacing corals on disturbed reefs, appeared particularly sensitive to warmer conditions, with their loss affecting the capacity of corals to rebuild, said the researchers.
"Our observations suggest that recovery processes will depend on such functional changes in reef communities, which in turn depend on how temperatures change the makeup of fish and invertebrates that live on the reefs," said Stuart-Smith, whose findings were published in scientific journal Nature.
"Although we are lucky that herbivorous fishes are not heavily targeted by fishing in Australia, our results highlight the potential for some ecologically important groups of reef animals to be disproportionately affected by warmer temperatures, particularly near the warm edge of their distributions.
"So as well as considering how to conserve and restore corals in areas affected by bleaching, we also need to consider how to maintain or build the broader fish communities that provide reef resilience."
