August 30, 2008

Giant Clam Discovered In Red Sea

Scientists have found a new species of giant clam in the Red Sea. It is the first new living species of giant clam that has been discovered in 20 years.

The species, Tridacna costata, accounted for more that 80% of local giant clams 125,000 years ago, but researchers now believe the species may be critically endangered.

The researchers suggest in Current Biology journal that their findings may represent one of the earliest examples of marine organism over-exploitation.
The species, which is ribbed and has a zig-zag shape to its outer shell, is set apart from other giant clam species because of its "very peculiar characteristics."

Live examples of T. costata seem to appear in very shallow waters, though some were found in deeper reef areas.

T. costata has an early breeding season that coincides with the seasonal plankton bloom.

"One of the great features of the desert-enclosed Red Sea is that you can literally time-travel from the present, several hundred thousand years into the past," said Dr Richter.

Richter believes that the stock of the giant clams plummeted around 125,000 years ago when modern humans first moved out of Africa and into the Red Sea area.  The giant clams would have been an easily accessible food source for hunter-gatherers.

The team of researchers also believe the clams shell size could have been much larger 125,000 years ago.

"The overall decline in giant clam stocks - with the striking loss of large specimens - is a smoking gun indicating over-harvesting," said Dr Richter.

The discovery comes as a shock to scientists.  They did not expect to find a new species in an area as well studied as the Red Sea.

Scientists said it is just another example of how little is known about marine biodiversity in general.

"The coral reefs in particular... may still harbor very large surprises," said Dr Richter.


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