Climate and anthropogenic driven disturbance threaten the viability of coral ecosystems. Substantial research effort is underway to identify interventions that enhance coral resilience. The Reef Song project recently quantified the role of coral-associated fish in promoting coral growth and survival following a natural thermal-stress event at Ningaloo Reef, Western Australia. This fish-coral relationship is proposed as a novel ecosystem approach for restoration, though its relative importance and synergy with other interventions requires further assessment prior to implementation.
We designed a novel modelling framework combining natural coral demographic data with data from adjacent experimental patch reefs indicating how manipulated fish (Dascyllus spp.) abundances modified coral growth (up to 80% increase) and post-bleaching survival (up to 25% increase). We simulated coral density, size distribution and cover under intervention scenarios and a mid-restoration natural heat-stress event, covering the effects of fish on vital rates crossed with various coral outplant densities. The long-term (decadal) recovery in coral cover is projected under each scenario to identify expected population-level recovery at scales relevant to restoration interventions. The findings quantify the expected long-term outcome of incorporating fish into restoration interventions, contrasted with coral-outplanting, and demonstrate a framework for assessing interventions and informing decisions on coral restoration actions.