The Marine chapter of the 2016 State of the Environment (SoE) report incorporates multiple expert templates developed from
streams of marine data. This metadata record describes the Expert Assessment The state and trends of ecological processes
– Crown-of-Thorns Starfish (COTS) outbreaks.The full Expert Assessment, including figures and tables (where provided), is
attached to this record. Where available, the Data Stream(s) used to generate this Expert Assessment are accessible through
the "On-line Resources" section of this record.
DESCRIPTION OF ECOLOGICAL PROCESS FOR EXPERT ASSESSMENT
COTS (Acanthaster planci) are natural predators of coral and occur on all coral reefs in Australia’s marine domain. High
fecundity means that when spawning coincides with favourable conditions, resulting recruitment can lead to outbreak densities
of large starfish that can deplete local coral cover within 3-5 years. Populations then collapse through starvation and
disease but not before they spawn abundant planktonic offspring, which may form secondary outbreaks on downstream reefs.
There have been four synchronised eruptions of secondary outbreak in the highly connected, archipelagic Great Barrier Reef
(GBR) since 1960. In the subsequent 15-20 years, multi-generational waves of secondary outbreaks have progressed southward
through the central GBR. Average coral cover on GBR reefs fell by half over 27 years of monitoring to 2012; about 40% of
the total decline was attributed to COTS. Outbreaks have also been recorded in all other parts of the starfish’s Australian
range (Far northern GBR, Torres Strait, northwest WA), but their significance is uncertain since systematic monitoring was
only recently implemented or is non-existent.
DATA STREAM(S) USED IN EXPERT ASSESSMENT
The assessment is based on data and analysis published in peer reviewed literature and unpublished reports. Details of specific
data sets used to generate the assessment have not been provided.
2016 SOE ASSESSMENT SUMMARY [see attached Expert Assessment for full details]
• 2016 •
Assessment grade: Poor
Assessment trend: Unclear
Confidence grade: Adequate high quality evidence and high level of consensus
Confidence trend: Adequate high quality evidence and high level of consensus
Comparability: Grade and trends are somewhat comparable to the 2011 assessment
• 2011 •
Assessment grade: Good
Assessment trend: Stable
Confidence grade: Limited evidence or limited consensus
CHANGES SINCE 2011 SOE ASSESSMENT
Since the 2011 assessment there has been widespread outbreaks of COTS detected across its range. There is a general lack
of information with which to determine long term trends and so trends are regarded as unclear rather than stable.
De’ath, G., Fabricius, K.E., Sweatman, H.P.A., Puotinen, M. (2012) The 27–year decline of coral cover on the Great Barrier
Reef and its causes. PNAS 109: 17995-17999
Doherty P.J., Coleman, G.J., Logan, M., MacNeil, M.A. (2015) Estimates of the abundance of the spawning stock of Crown-of-Thorns
Starfish on the northern Great Barrier Reef in 2013-14 and reflections on the effectiveness of starfish control. Unpublished
report for the Department of the Environment, Australian Government. Australian Institute of Marine Science, Townsville
Fabricius, K.E., Okaji, K., De'Ath, G., 2010. Three lines of evidence to link outbreaks of the crown-of-thorns seastar Acanthaster
planci to the release of larval food limitation. Coral Reefs 29: 593-605.
Pratchett, M.S., Caballes, C., Rivera-Posada, J.A., Sweatman, H.P.A. (2014) Limits to understanding and managing outbreaks
of crown-of-thorns starfish (Acanthaster spp). Oceanogr. Mar. Biol. Ann. Rev. 52: 133–200
QUALITY OF DATA USED IN THE ASSESSMENT
CUSTODIAN AND LOCATION OF DATA
Australian Institute for Marine Science (details of specific data sets used to generate the assessment have not been provided).
METHOD USED TO DETERMINE STATE OR RECENT TREND
Expert assessment based on information in peer reviewed literature and unpublished reports.
When citing this Expert Assessment in a list of references use the following format:
citation author name/s (year metadata published), metadata title. Citation author organisation/s. File identifier and Data
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