Post on 18-Dec-2015
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Acanthaster planci
Biological ClassificationDomain :
Kingdom :
Phylum :
Class :
Order :
Family :
Genus :
Species :
Eukaryota
Animalia
Echinodermata
Asteroidea (sea stars)
Valvatida
Acanthasteridae
Acanthaster (2 species)
Acanthaster planci
Acanthaster planci
EchinodermataCharacteristics:• Bilateral symmetry as larvae• Pentaradial symmetry as adults• Spiny/bumpy endoskeleton• Water vascular system • Tube feet
Acanthaster planci
AsteroideaCharacteristics:• up to 50 arms
• tube feet protrude from the oral surface
• Multi-directional movement
• endoskeleton made up of calcium carbonate plates
• Pedicellariae
Acanthaster planci
Crown-of-ThornsFlattened sea star
Large central disk
7-23 arms
Elongated spines
Multi-colors
Acanthaster planci
AnatomyIn the aboral surface:- anus- madreporite(s)
In the arms :- ambulacral grooves- spines- podium (feet)- digestive glands
Acanthaster planci
ReproductionSexual reproduction
A female can release up to 60 million eggs in one season
No asexual reproduction
Acanthaster planci
World Heritage Criteria
• being an outstanding example representing significant ongoing geological processes, biological evolution and man's interaction with his natural environment;
• containing unique, rare and superlative natural phenomena, formations and features and areas of exceptional natural beauty; and
• Providing habitats where populations of rare and endangered species of plants and animals still survive
• being an outstanding example representing a major stage of the earth’s evolutionary history
Acanthaster planci
Effects of Outbreaks
57% of all outbreak reefs lost 30-50% of their coral
1979 – 1991 Outbreak
ON AVERAGE the last outbreak episode caused a 3.4 foldincrease in the amount of dead coral than normal
Acanthaster planci
• Natural phenomenon?• Female ability to produce 60 million eggs• Have outbreaks been ocurring for 3000-7000 years?• Are human activities responsible for the
worsening/increased frequency of outbreaks?
Increased nutrient run-off from the land increases the amount of phytoplankton in the water = greater survival
of larvae
OR
Fishing and shell collecting have led to decreased
numbers of predators of the crown of thorns
Causes of Outbreaks
Acanthaster planci
Current Policy
• No large-scale interference
• Close monitoring through three major programs
Acanthaster planci
Summary …outbreaks can cause significant disturbance to coral
reefs over a wide geographic area… despite considerable scientific research, the cause of … outbreaks and the role of human activities as a causal factor are unknown. Consequently management activities are confined to accurately assessing the current extent and intensity of the outbreak, and to providing advice on crown-of-thorns starfish control measures for particular sites.
Acanthaster planci
For more information and regular updates visit:
www.gbrmpa.gov.auand look for “State of the Reef Report” updates