What was the largest clam ever found? The shell of the largest clam Tridacna gigas can grow to be 4.6 feet (1.4 m) across and weigh over 500 pounds (227 kg). These giant clams are found in the warm waters of the Indo-Pacific ocean. Their heavy shells must be braced by external structures to prevent the mollusks from toppling over. Tridacna gigas anchor themselves to coral reefs using byssal threads. These are strands made of the strong, fibrous protein byssus. As filter feeders giant clams lack complex organ systems. They do not have a centralized nervous system or circulatory system. Oxygen and nutrients are absorbed directly across the mantle tissues. Tridacna gigas feed by siphoning phytoplankton from the water and filtering it from mucus on their gills. Although their shells are large Tridacna gigas cannot completely close them. Their soft mantles are partly exposed making giant clams vulnerable to predation. As a result numbers are declining due to over harvesting. Giant clams reach their immense sizes by living exceptionally long lifespans. Some have been documented as over 100 years old.
Do giant clams make giant pearls?
Why do giant clams get so big?
Why get giant clams so big? Some think big shells useful to anchor in sand. Others say reached large sizes in past. Now too few giants to breed well. So no good reason left for bigness. Just remnants of former time still around.
Why is giant clam near extinct?
The giant clam is endangered due to overharvesting and habitat loss. All species are protected but populations continue to decline. Their large size made them easy targets for humans. Stories depict them as aggressive, but they are gentle giants. They close their shells in response to movement to protect themselves.
The largest ever discovered weighed 250kg. Today shell crafts are still sold, threatening wild populations. Without conservation, they could fade into extinction. Families farm them in “clam gardens” by stilt houses in Pacific archipelagos. Their shells cache valuables and ancestral skulls. Nine species are considered threatened. International trade must be traceable and sustainable.
They remained easy food supplies for early human migration from Africa. With no ability to hide or flee, they exemplify the first ocean overexploitation, now a major issue. Unlike reef species, they remain in one spot on the ocean floor for life. They live in broken coral and sand. Populations are declining near China, Malaysia and the Philippines.