Environment

New giant clam species discovered; early example of human sea-life exploitation

by Tina Kells | August 30, 2008 at 01:03 pm

994 views | 21 Recommendations | 4 comments

A new species of giant clam, Tricanda costata, has been discovered by German scientists in the Red Sea basin. Believed to be well over 125,000 years old the new species is said to have once dominated the Red Sea ecosystem and may be one of the earliest examples of human over-exploitation of marine life.

"The new species are mid-sized clams - up to 40cm long and a couple of kilograms heavy," explained co-author Dr Claudio Richter, from the Alfred-Wegener Institute for Polar and Marine Research, Germany.

The new species has a distant relative, T. gigas, which can grow up to 1.4m long.

Live specimens of T. costata appear to be restricted to very shallow waters. Other species were also found in deeper reef zones.

The clam has an earlier and shorter breeding season that coincides with the seasonal plankton bloom. Genetic analysis confirmed the status of the new species.

Well preserved fossil records show that at one point T. costata accounted for 80% of the area's giant clam population. The population suffered a sudden dramatic decline 125,000 years ago; the same time modern humans are believed to have first appeared in the region.

Giant clams were abundant, large in size and easily accessible - making them an attractive food source for hunter-gatherers.

In "pre-human times", T. costata may have been up to 60cm long. Since then, shell size has also decreased dramatically.

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

Only a few specimens of the giant clam remain today prompting scientists to immediately declare the newly discovered species as critically endangered. The Red Sea is a well studied area and scientists were both surprised and excited by the implications of the new discovery.

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

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Barbara McPherson

flagged this story as Good Stuff

at 13:10 on August 30th, 2008

Tina Kells, I like this story. It's good stuff. Goes to show there's always something new to learn.

Daniel Neun

flagged this story as Good Stuff

at 09:33 on September 1st, 2008

Fascinating.

rpshen

flagged this story as Good Stuff

at 13:09 on September 2nd, 2008

Tina Kells, I like this story. It's good stuff. Very nicely written story.

Nick Hobgood

at 03:24 on September 8th, 2008

Tridacna gigas photo with diver was taken in East Timor where giant clams are being harvested for food at unsustainable levels. This individual was found at depths that are inacessible by local free divers who harvest the clams.