Reef structures and stabilisation
Repairing damaged reef surfaces
When reefs are damaged (for example by storms, ship groundings or coral bleaching) the dead or degraded coral can become loose and unconsolidated, making it difficult for coral to regrow.
Mesh or netting is sometimes installed over the rubble to prevent further movement. Often, young corals are then transplanted onto the damaged area, or on artificial reef structures. This technique is relatively common in the US, funded by insurance claims following ship strikes; however, there is a lack of published information and research about this technique.
To date these methods have been limited to small, localised sites. New approaches would need to be developed for this to be applied at larger scales.
Novel human-made structures
Aim to enhance reef structural complexity, and provide surfaces to promote coral settlement and growth. They can range from micro-scale engineering to artificial reefs.
Novel, human-made structures for coral settlement (new shapes, sizes and surfaces) can promote coral settlement and growth. One method uses small, re-seeding units (such as the tetrapods developed by SECORE) that allow corals raised in aquaculture – or collected from wild spawn slicks - to be placed on natural reefs with minimal handling. This significantly reduces time spent re-locating and planting cultured corals. Millions of these type of units could be deployed to accelerate recovery at large scales.
At more local scales, artificial reefs have been constructed from a variety of materials to provide a suitable structure for coral settlement and reef function. They range in size from clusters of reef balls (1-3m diameter) to reef frameworks extending over hundreds of metres. Work is underway to test the effect of reef surface shape, aspect and other factors to maximise coral larval settlement and survival.
Photos by Dr Andrew Negri