TED日本語 - メイ・リン・ネオ: オオジャコガイの知られざる魅惑的生態

Back home, my friends call me nicknames, such as "The Giant Clam Girl," "Clam Queen," or, "The Mother of Clams."

(Laughter)

This is because every time I see them, I talk nonstop about giant clams all day, every day. Giant clams are these massive and colorful shelled marine animals, the largest of its kind. Just look at this shell. The biggest recorded individual was four-and-a-half-feet long and weighed about 550 pounds. That is almost as heavy as three baby elephants.

South Pacific legends once described giant clams as man-eaters that would lie in wait on the seabed to trap unsuspecting divers. A story goes that a diver had lost his legs while trying to retrieve a pearl from a giant clam. I thought, "Really?" So out of curiosity, I did an experiment using myself as bait.

(Laughter)

I carefully placed my hand into the clam's mouth and waited. Hmm ... I still have my hand. It seems that these gentle giants would rather retreat and protect their fleshy bodies than feed on me. So much for those killer clam myths!

Unfortunately, the reality is, we are the giant clams' biggest threat. Considered a delicacy throughout the Western Pacific and Indian Oceans, giant clams have been traditionally fished as seafood. Fishermen are particularly interested in their adductor muscles, which are organs that hold the two shells together like a hinge. Just for their muscles, giant clams were almost hunted to extinction between the 1960s and 1980s. Clamshells are also popular in the ornamental trade as jewelry and for display. In the South China Sea, fishermen went out of their way to collect fossilized clamshells by digging through large areas of coral reefs. These were later carved and sold as so-called "ivory handicrafts" in China. Giant clams, dead or alive, are not safe from us. It's a "clamity!"

(Laughter)

(Applause)

With the spotlight on more charismatic marine animals such as the whales and coral reefs, it is easy to forget that other marine life needs our help, too. My fascination with giant clams got me started on conservation research to fill in the knowledge gaps on their ecology and behavior. One of the discoveries that we made was that giant clams could walk across the seafloor. Yes, you heard me right: they can walk.

To find out, we placed numerous baby clams on a grid. Now watch what happens over 24 hours. We think that walking is important for getting away from predators and finding mates for breeding. While it can hard to imagine any movement in these enormous animals, giant clams up to 400 pounds can still walk, they just move slower.

During my PhD, I discovered more secrets about the giant clams. But there was something missing in my work. I found myself asking, "Why should people care about conserving giant clams?" -- other than myself, of course.

(Laughter)

It turns out that giant clams have a giant impact on coral reefs. These multitasking clams are reef builders, food factories, shelters for shrimps and crabs and water filters, all rolled into one. In a nutshell, giant clams play a major contributing role as residents of their own reef home, and just having them around keeps the reef healthy. And because they can live up to 100 years old, giant clams make vital indicators of coral reef health. So when giant clams start to disappear from coral reefs, their absence can serve as an alarm bell for scientists to start paying attention, similar to the canary in a coal mine. But giant clams are endangered. The largest clam in the world is facing the threat of extinction, with more than 50 percent of the wild population severely depleted. And the ecological benefits of having giant clams on coral reefs are likely to continue only if populations are healthy, making their conservation paramount.

So I stand here today to give a voice to the giant clams, because I care a whole lot for these amazing animals, and they deserve to be cared for. It is time for the giant clams to step out of their shells, and show the world that they, too, can be the heroes of the oceans.

Thank you very much.

(Applause)