What is the biggest bivalve mollusk, cephalopod mollusk, and crustacean known to man?
The biggest bivalve mollusk is the clam Tridacna, native to the Indo-Pacific, which reaches a weight of 500 pounds. The giant squid, nearly sixty feet long, is the biggest cephalopod. The Alaskan king crab is the largest of the crustaceans, weighing up to 15 pounds, and measuring four to five feet across shell and claws. King Crab, (Crab Photo by Bjrn T. Forberg) What do oysters and clams eat? Called filter feeders, oysters and clams eat plankton. By pumping water through their bodies, the mollusks strain the microscopic organisms through their gills, which act as sieves. Clams seem to squirt water through their siphons. What purpose does the siphon serve? Three main purposes: breathing, obtaining food, and eliminating waste products. Since clams are relatively immobile and movement is usually limited to burrowing in the sand, their double-tubed siphon–which operates much like a snorkel–is their lifeline. Inflowing water is pumped through the siphon, passed over the gills, and strain
