Corals

Corals are pretty... amazing. Most South Africans are familiar with the beautiful coral reefs in northern KwaZulu-Natal. In the warm light infused water of the Indian Ocean these sunlight powered communities support an amazing diversity of fishes and a thriving scuba diving industry that is a key aspect of South Africa’s marine tourism economy. Further offshore there are deep water corals in the twilight zone of the iSimangaliso MPA and some deeper water species in this area rely on both algae in their tissues to make sugars and also filter food from the water. Scientists are increasingly interested in coals in deeper water because of the evolutionary history of coral and algae symbiosis and because these deeper reefs may be increasingly important in this era of climate change. The globally important role of coral communities in iSimangaliso are recognized as vital to climate adaptation and mitigation. Management needs to ensure that anthropogenic stressors and disturbances on coral reefs are kept to a minimum to maintain and enhance coral reef resilience in the face of anticipated future warming events.

 The warm and cool temperate reefs of South Africa also provide homes for corals particularly soft corals and seafans – many of which are found nowhere else on earth. Deep and cold water coral communities also occur in the outer shelf, shelf edge and slope all around South Africa although our knowledge of these species is still limited. This is an area of active research in South Africa. Deep water corals include stony corals (the same groups that dominate shallow coral reefs); soft corals including seafans, cauliflower and thistle corals; lace corals. Different species within all these groups occur on the west, south and east coast which means that the fragile ecosystems that support these deep water corals need protection in each region. Coral habitats are sensitive to activities that impact the seabed including bottom trawling, petroleum activities, mining and anchoring. Sedimentation including from poor catchment management, offshore drilling and mining and even trawling can affect deep water corals.

On the west coast Childs Bank protects unique coral communities on the rocky slopes. Although trawling has damaged corals in this area, remaining patches of corals on the steep slopes can support coral recovery. Live and fossilised corals have been collected in the vicinity of Browns Bank Corals that may hold important clues about South Africa’s climate past. The SWIS1 section of the Southwest Indian Seamounts MPA includes a range of deep water coral species and the steep area provides a range of oceanographic conditions to support climate resilience. The Port Elizabeth Corals MPA is a unique feature that includes hard and soft coral taxa from the slope. Amathole Offshore MPA includes a high diversity of lace corals and stony corals. Aliwal Shoal MPA and Protea Banks MPA support different hard and soft coral species in deep water with particularly surprising coral diversity and a high abundance of large black coral trees on the outer shelf reefs and shelf edge of uThukela Banks MPA.