Threats listed in assessment
In the Gulf, the major threats to corals include extreme and increasing temperature variability due to climate change, as well as direct destruction and increased turbidity caused by coastal construction (Riegl et al. 2012). Although bleaching thresholds in the Gulf are the highest recorded in the world (Riegl et al. 2012), bleaching events in the UAE have resulted in significant mortality (such as in 1996-1998, 2002, 2010 and 2017) and slow recovery (Burt et al. 2008). In Abu Dhabi, the most recent coral bleaching event resulted in nearly 95% of corals bleaching, and by April 2018, mortality reached 73% (Burt et al. 2019). This event resulted in mass mortality of even the more stress-tolerant corals such as poritids and merulinids (Burt et al. 2019). Coastal development, particularly large-scale offshore real estate developments and sedimentation associated with reclamation, has directly buried coral reefs in the Gulf (Burt et al. 2008, 2013; Burt 2014; Burt and Bartholomew 2019).Globally, the major threat to corals is global climate change, in particular, temperature extremes leading to bleaching and increased susceptibility to disease, increased severity of ENSO events and storms, and ocean acidification. Other threats include the crown-of-thorns starfish (Acanthaster planci), which has been observed preferentially preying upon corals of the genus Acropora (Colgan 1987). These voracious predators of reef-building corals are found throughout the Pacific and Indian Oceans, and the Red Sea. Populations of the crown-of-thorns starfish have greatly increased since the 1970s and have been known to wipe out large areas of coral reef habitat. Increased breakouts have become a major threat to some species, and have contributed to the overall decline and reef destruction in the Indo-Pacific region. The effects of such an outbreak include the reduction of abundance and surface cover of living coral, reduction of species diversity and composition, and overall reduction in habitat area. Coral disease has emerged as a serious threat to coral reefs worldwide and a major cause of reef deterioration (Weil 2006). The numbers of diseases and coral species affected, as well as the distribution of diseases have all increased dramatically within since the 1990s (Porter et al. 2001, Green and Bruckner 2000, Sutherland et al. 2004, Weil 2004). Coral disease epizootics have resulted in significant losses of coral cover and were implicated in the dramatic decline of acroporids in the Florida Keys (Aronson and Precht 2001, Porter et al. 2001, Patterson et al. 2002). In the Indo-Pacific, disease is also on the rise with disease outbreaks recently reported from the Great Barrier Reef (Willis et al. 2004), Marshall Islands (Jacobson 2006) and the northwestern Hawaiian Islands (Aeby et al. 2006). Increased coral disease levels on the Great Barrier Reef were correlated with increased ocean temperatures (Willis et al. 2004), supporting the prediction that disease levels will be increasing with higher sea surface temperatures. Escalating anthropogenic stressors combined with the threats associated with global climate change of increases in coral disease, frequency and duration of coral bleaching and ocean acidification place coral reefs in the Indo-Pacific at high risk of collapse.Localized threats to corals include fisheries, human development (industry, settlement, tourism, and transportation), changes in native species dynamics (competitors, predators, pathogens and parasites), invasive species (competitors, predators, pathogens and parasites), dynamite fishing, chemical fishing, pollution from agriculture and industry, domestic pollution, sedimentation, and human recreation and tourism activities.
Conservation measures notes:
Required conservation measures: