The Hurghada Environmental Protection and Conservation Association (HEPCA) is calling for divers at Careless Reef to report sightings of the Crown-of-Thorns starfish. They want to know
- how many COTs you saw
- at what depth you saw them
- the approximate size
and have provided a form you to fill in.
The Crown-of-Thorns starfish (COTS), Acanthaster planci eats corals by extruding its stomach out through the mouth and turning it inside out: a process called aversion. The stomach secrets digestive enzymes onto the coral and then absorbs the digested tissue while withdrawing. As the feeding process takes from 4 to 6 hours, Crown of Thorns starfish can feed once or twice a day. This means that a single animal can consume a coral area one and a half times its size. The crown-of-thorns starfish is an unusually large starfish and which grows to more than 1 m in diameter. It has up to 21 arms, with the entire upper surface of its body covered in long venomous spines. The starfish can move up to 20 m in an hour.
A few of these starfish on the reef do not damage it and are part of the marine ecosystem like so many other species. However, when they occur in high densities they can devastate large areas of coral.
Outbreaks like this can occur at regular intervals with coral cover returning to pre-outbreak levels in the intervening years. The last outbreak at Careless Reef was in the spring of 2011, when divers collected more than 400 COTS from the site. The following year at about the same time, a spot outbreak occurred and HEPCA then initiated a community based monitoring/reporting program.
Over the past weeks HEPCA is once again receiving reports of multiple COT sightings and are closely monitoring the situation.
Each female starfish can produce up to 60 million eggs during a single spawning season. The starfish tend to gather together to spawn which increases the chance of fertilising the eggs. Fertilisation rates for crown-of-thorns starfish are the highest measured for any invertebrate. Therefore, a small population of crown-of-thorns starfish could potentially produce a very large number of offspring.
Further Reading:
HEPCA
CRC Reef Research Centre
