The dazzling blue and yellow of this giant clam (Tridacna gigas) may soon disappear from our oceans forever. The International Union for Conservation of Nature (IUCN) has classified the marine giant as endangered. A new population assessment has shown that populations of the mussel, which grows up to 1.40 meters tall and weighs over 300 kilograms, has declined by 84 percent over the past century. It is even locally extinct, for example in the sea around Taiwan.
In addition to overfishing of mussels, climate change is also causing their population decline. Similar to corals, they live in symbiosis with algae: the giant clams offer the algae protection and benefit from the oxygen and nutrients that the algae produce through photosynthesis. However, if the sea water becomes warmer due to climate change, the giant clams will reject the food-producing algae. This can cause the mussels to starve.
A potential extinction of the mussels would not only be a shame for the beauty of the sea giants, but also problematic due to their important role in the ecosystem: “Together with coral reefs, these mussels provide important habitats for other creatures that live in the reefs,” explains Ruiqi Li from the University of Colorado. “They are also important nutrient producers in shallow seawater where there is normally no food. If the giant clam goes extinct, it will have significant ecological impacts on the tropical oceans.”
But how could the extinction of the giant clam be prevented? The United States National Oceanic and Atmospheric Administration (NOAA) has proposed placing Tridacna gigas and nine other giant clam species under the Endangered Species Act. If the proposal is approved, giant clams would be protected by law in the United States and wild specimens would not be allowed to be harvested or traded in the future.