INFLUENCE OF HYDRODYNAMICS ON THE PASSIVE DISPERSAL AND INITIAL RECRUITMENT OF LARVAE OF ACANTHASTER-PLANCI (ECHINODERMATA, ASTEROIDEA) ON THE GREAT-BARRIER-REEF

Numerical hydrodynamic and particle dispersion simulations showed that neutrally buoyant larvae are subject to a complex circulation pattern which induces a spatial variability in their relative numbers. The interaction of tidal, wind and gradient-driven flows with the reef were found to cause some areas within individual reefs to retain higher numbers of larvae than others. These locations were compared with diver observations of the abundance of Acanthaster planci (L.) at the beginnings of outbreaks and a clear correspondence was found in all 6 simulated cases. Results suggest that hydrodynamics have a major influence on not only the dispersal of larvae of A. planci but also perhaps the location of their initial recuitment. Surveillance of these locations may provide an 'early warning' strategy for monitoring and controlling future outbreaks of this starfish on reefs.