Australia’s Great Barrier Reef (GBR) is a vast coral reef ecosystem consisting of 3800+ individual reefs. Ocean currents connect populations of coral and other benthic organisms by dispersing their larvae among the reefs. Connectivity is also a major driver of regional dynamics for coral-eating crown-of-thorns starfish (COTS), whose periodic population explosions have had devastating impacts on the health of the GBR. While large populations of adult starfish can devastate the coral community on a reef, dispersal of starfish larvae to other reefs leads to large-scale outbreak events and subsequent regional declines in coral cover. Efforts to control these outbreaks are exacerbated by the spatial scale of the GBR, and warrant targeted allocation of management resources at strategic locations. Here, we first used the oceanographic models to simulate the dispersal of both COTS and coral larvae among the reefs and obtain GBR-wide connectivity patterns. We then analyzed these connectivity patterns in order to highlight reefs that will be more likely to either experience larval influx or spread the larvae to other reefs in the region. To test the capability of the connectivity models to capture the demographic processes on the GBR, we validated the model outputs against COTS field surveys, and found that the predictions of COTS larval connectivity correspond to reported adult abundances on reefs. We then used these outputs to define connectivity profiles of reefs that can then be used as a basis for designing regional control and management strategies. Importantly, in addition to identifying reefs important for COTS connectivity, this approach also identified potential sources of coral larvae that can support regional recovery processes, and do so consistently over multiple spawning seasons. Protecting these regionally important source reefs may be critical to help with the recovery of reefs that have not only already been damaged by COTS outbreaks, but also affected by other disturbances such as coral bleaching. This analysis has been designed to support on-water decision making processes, and its outputs are now being integrated into the Great Barrier Reef Marine Park Authority’s expanded COTS Control Program that willguide future allocation of management resources and effort. Keywords (Please supply 5 keywords) Connectivity, crown-of-thorns starfish, dispersal, spatial planning, spatial prioritisation, pest management Author email addresses (phone number of you wish but not required) k.hock1@uq.edu.au,Mary.Bonin@gbrmpa.gov.au,k.critchell@uq.edu.au,Scott.Condie@csiro.au, David.Westcott@csiro.au,p.j.mumby@uq.edu.au
