Acanthaster planci invasions: applying biosecurity practices to manage a native boom and bust coral pest in Australia

Coral reef systems are in global decline. In Australia, much of this decline has been attributable to cyclic outbreaks (every ~17 years) of the coral-feeding crown-of-thorns seastar. While a native species, when in large enough densities the seastar acts like an invasive pest. Since 2012 the Australian government has invested significantly in a targeted control program using lethal injection. While this program is effective for individual reefs, it is not a complete strategy for the entire Great Barrier Reef (~2,500 reefs). In order to find a longer-term solution to the problem, in 2015, the lead author travelled to New Zealand, the United States, and Canada under a Churchill Fellowship to understand successful aquatic integrated pest management strategies and their potential application to the Great Barrier Reef. Meetings and workshops were convened with experts who specialise in risk assessment, categorisation, and management of aquatic invasive species. The experts comprised academics, applied scientists, policy makers, and a not for profit community based invasive species council. Bioinvasion management and prioritisation of management effort using risk-based frameworks were reviewed for application to the crown-of-thorns seastar. This viewpoint is novel in its approach of applying invasive species tools and perspectives to a non-invasive, native marine pest. Early detection and rapid response is key to preventing the transition of the seastar from natural densities to outbreak densities. However given the seastar is a native species already established, when in outbreak mode a multifaceted post-border management approach is essential. Private support funding models, that bridge conservation and tourism/philanthropy have proved successful in New Zealand to supplement government funded marine reserve management – this is an approach which should be explored by Australia to help manage the seastar. Dedicated support and commitment is needed to break the issue-attention cycle. On the Great Barrier Reef, a dedicated biosecurity approach should be used to maintain the seastar at natural densities, increase the time between outbreaks, protect coral cover and increase resilience of the system.