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CROWN-OF-THORNS STARFISH SPARK A PRICKLY DEBATEA CRC Reef report released today will help stimulate scientific debate that could ultimately unravel the puzzle of what causes outbreaks of crown-of-thorns starfish. The report found large numbers of juvenile crown-of-thorns starfish on 19 mid-shelf reefs in the Cairns and Central sections of the Great Barrier Reef between October 1999 and April 2000. The report suggests that they could be the start of a new outbreak of crown-of-thorns but scientific opinion is divided on the issue. "The discovery of large numbers of juvenile crown-of-thorns starfish might be considered as evidence that a new outbreak of starfish is looming," said Dr Williams. "But we have seen a second or third settlement of crown-of-thorns starfish onto the same reef during previous major outbreaks." New surveys will be conducted this year to follow the fate of the young crown-of-thorns starfish. "The new surveys by CRC Reef will check the fate of the young crown-of-thorns starfish and determine whether, since there is very little hard coral cover remaining on some of these reefs, they were able to survive," says Dr David Williams. The report also suggests that crown-of-thorns outbreaks could be occurring more frequently. But this is also the subject of scientific debate. The first outbreak of crown-of-thorns starfish was detected on the reefs around Green Island off Cairns in 1962. Since then, there have been three documented waves of outbreaks of crown-of-thorns starfish. "With no historical information about outbreaks of crown-of-thorns starfish on the Great Barrier Reef prior to the 1960s, it is difficult to know whether the waves of outbreaks are becoming more frequent," said Dr Williams. "The new surveys are another step toward understanding the dynamics of an outbreak of crown-of-thorns starfish," he said. "Most importantly, they will give us more information to begin to look at links between crown-of-thorns starfish outbreaks and possible causes, such as freshwater run-off from the land." For more information or a copy of the CRC Reef report Crown-of-thorns
starfish (Acanthaster planci) in the central Great Barrier Reef
region. Results of fine-scale surveys conducted in 1999-2000 by Udo Engelhardt
and 9 co-authors contact: Dr David Williams, Deputy CEO, CRC Reef Research
Centre Ltd on 07 4729 8409 or 0419 679753. |
