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

Abstract

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.

Thirty Years of Research on Crown-of-Thorns Starfish (1986–2016): Scientific Advances and Emerging Opportunities

“…This lack of planning, combined with inevitable diversion of research and management focus during non-outbreak periods [249] and limited capacity to detect the early onset of outbreaks, results in inevitable delays in responding to new outbreaks [250]. The issue is even more complex and more pronounced outside of the GBR where there is no apparent pattern to the timing and location of outbreaks.…”

“…The issue is even more complex and more pronounced outside of the GBR where there is no apparent pattern to the timing and location of outbreaks. A proactive management policy with dedicated funding that can be immediately accessed when initiation of future outbreaks are imminent or actually detected is sorely needed and currently lacking [249]. Ongoing control programs across the Indo-Pacific are estimated to have cost up to US $44 million [1], and have been largely ineffective in protecting reef systems from outbreaks of Acanthaster spp.…”

“…Moreover, it is important to maintain research and management traction throughout non-outbreak periods (Figure 4), both to address significant knowledge gaps pertaining to the dynamics of non-outbreak populations and to consider additional preventative actions (e.g., sustained culling of low density populations) that may further increase management effectiveness. is sorely needed and currently lacking [249]. Ongoing control programs across the Indo-Pacific are estimated to have cost up to US $44 million [1], and have been largely ineffective in protecting reef systems from outbreaks of Acanthaster spp.…”

Age and Growth of An Outbreaking Acanthaster cf. solaris Population within the Great Barrier Reef

“…Moreover, minimizing or preventing outbreaks of Acanthaster spp. is considered one of the foremost management strategies to reverse sustained coral loss on the GBR (e.g., [6]). Effective management of CoTS outbreaks is, however, currently constrained by limited knowledge of CoTS demography [5,7], which is fundamental to understanding both the proximal and ultimate causes of outbreaks [8].…”

Environmental Tipping Points for Sperm Motility, Fertilization, and Embryonic Development in the Crown-of-Thorns Starfish

“…Reproductive success is central to explaining periodic increases in local densities [7]. Understanding the critical events in the early life history of CoTS is key to identifying population bottlenecks that could be strategically targeted to improve control programs and mitigate coral mortality [8]. Despite this, environmental drivers of variation in reproductive success for Acanthaster spp.…”