Hoey AS, Harrison HB, McClure EC, Burn D, Barnett A, Cresswell B, Doll PC, Galbraith G, Pratchett MS (2021) Coral Sea Marine Park Coral Reef Health Survey 2021. Report prepared for Parks Australia.

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• Coral Sea Marine Park Coral Reef Health Survey 2021

About the report

The 2020-21 survey is a continuation of the 2018-2020 survey, one of the largest coral reef monitoring and research projects in the Coral Sea Marine Park, undertaken in partnership between Parks Australia and the ARC centre of excellence for Coral Reef Studies at James Cook University.

In early 2020 shallow reef habitats across the Coral Sea Marine Park experienced severe and widespread bleaching, with 63% of all corals surveyed across the Coral Sea Marine Park, and up to 89% of corals at individual reefs being bleached.

The 2020-21 project assessed the impacts of the 2020 bleaching event on the condition of fish, invertebrate and benthic communities, and gained some understanding of the potential resilience and recovery of corals throughout the Coral Sea Marine Park. The project surveyed 43 sites and over 13 km of reef habitat across 13 reefs.

The surveys revealed that total shallow water coral cover decreased from 28% in 2020 to 17% in 2021 across the Coral Sea Marine Park, a mean decline of 39%. Large-scale coral mortality commonly leads to declines in reef-associated taxa that rely on corals for food or shelter. There were declines in the species richness, abundance, and biomass of reef fishes within the central Coral Sea Marine Park.

Despite the reported decrease in the biomass of reef fish, the Coral Sea Marine Park still has high fish biomass as well as several standout or “bright spot” reef areas with high coral and fish densities compared to coral reefs in the Great Barrier Reef and globally.

Parks Australia is using the research results to plan longer-term research and monitoring in the Coral Sea Marine Park to understand the importance of ‘bright spot’ reefs as centres of resilience and refuges from disturbance events.