The Acanthaster Phenomenon: A Modelling Approach Rapporteurs’ Report

Stable limit cycles at the scale of individual reefs and hydrodynamic connections between reefs for larval transport are together sufficient to account qualitatively for the large scale dynamics of the phenomenon. Several different factors may generate the stable limit cycles, and these need not be mutually exclusive, but rather reinforcing. An important factor in the limit cycle dynamics in other areas is fish predator pressure on the starfish; increased pressure can suppress limit cycle behaviour. There is some evidence that the same factor may have been coercive on the GBR. Fish predator pressure may have been reduced through the intensification of fishing in the 1960s, leading to the two waves of outbreaks experienced on the GBR since then. There is a possibility that successive waves of outbreaks could degrade the system.