Our rapidly changing climate and its impacts on marine ecosystem health is the biggest threat to coral reefs globally. Of concern are ongoing shifts in coral species composition on reefs and changes in coral recruitment due to the increased frequency of extreme climate-driven events. Increasing sea temperatures resulting in marine heatwaves is a major cause of coral stress and death. Reefs in central and western Torres Strait were impacted by the global bleaching events in 2016, 2017 and 2020.
The full extent of these impacts is unknown as there has been little monitoring of reefs in Torres Strait since the 2016 bleaching event. However, as of 2021, monitoring of critical coral reef sites has been re-instigated. Broader regional monitoring of coral reef health, and its integration with traditional ecological knowledge and observations, remains a priority.
Prior to catastrophic losses of corals in 2016, coral reefs were assessed to be in good condition in 2015 with high coral cover and species diversity, and minimal incidence of disease. The presence of Crown-of-Thorns Starfish (COTS) was recorded on all surveyed sites, with densities of possible concern around Erub and Mer. Surveys in 2021 over the eastern reefs (where coral cover remains high) observed COTS in significant numbers.
Given indications of declines in local coral species diversity, recruitment, and poor recovery from the 2016 mass bleaching event, the 2021 condition for coral reefs is assessed to be of ‘significant concern’.