Acanthaster planci

Acanthaster planci

Crown-of-Thorns Starfish

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

Crown-of-Thorns

Acanthaster planci

AnatomyIn the aboral surface:- anus- madreporite(s)

In the arms :- ambulacral grooves- spines- podium (feet)- digestive glands

Acanthaster planci

Distribution & Habitat

Acanthaster planci

ReproductionSexual reproduction

A female can release up to 60 million eggs in one season

No asexual reproduction

Acanthaster planci

Regeneration

Lif

e C

ycle

Acanthaster planci

Life Cycle

Lif

e C

ycle

Lif

e C

ycle

Lif

e C

ycle

Lif

e C

ycle

Acanthaster planci

Predators

Acanthaster planci

Predators

Acanthaster planci

Th

e G

reat

Barr

ier

Reef

Acanthaster planci

The Great Barrier Reef

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

Outbreaks

Acanthaster planci

Effects of Outbreaks

Acanthaster planci

OUTBREAKSRecorde

dOutbrea

ks1962 – 1976

1979 – 1981

1993 - date

Acanthaster planci

Monitoring

Acanthaster planci

Monitoring

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

Acanthaster planci

Other Sources:www.reef.crc.org.auwww.aims.gov.au