Reef Report for Friday, June 20, 2008
Crown of Thorns Populations in Decline on the Great Barrier Reef
New scientific survey is good news for hard corals, but other threats exist.
The Australian Institute of Marine Science today released a report summarizing a long series of reef surveys made in 2007 along the entire Great Barrier Reef.
The survey methodology is pretty amazing; a diver is towed behind a boat at a designated speed, and makes a count of Crown of Thorns Starfish.
These counts are tabulated by date and location, and compared with other survey years and reefs to gain an understanding of any change in the populations of these coral-eating starfish.
While in earlier issues we reported that Crown of Thorns populations were in decline, this time the data is clearer. Populations of COT Starfish are the lowest in 20 years. This is good news, as hard corals will be able to grow and reproduce more quickly without the destructive "grazing" activities of these starfish.
Little is understood about the population dynamics of COT Starfish, three times since 1960 there has been a dramatic increase of these starfish, followed by their decline. Itís hoped that ongoing research will shed a bit of light on what causes these outbreaks, and whether or not human activities are linked to them.
In the world of today, no environmental news is all good news, and in this case scientists doing the surveys noted that a suite of coral diseases collectively called "white syndrome" is more noticeable in some parts of the reef, and much research is ongoing to learn more about this problem. So far the problem is scattered and patchy in distribution, and seems to come and go in a given location over time.
News coverage of this story, from The Age.
Summary, from the Australian Institute of Marine Science.
The full annual report of the Great Barrier Reef Long Term Monitoring Program.
The weekly reef report is written by Joel Groberg of DiveTheReef.com,
who compiles them from the many conversations he has with dive staff in the area, as well as† many other local sources in the dive
Index of all reef reports.