What Is An Abalone?
Related to the limpets, the abalone is considered the genus of all single shelled mollusc. Learn all about the abalone!
Related to the limpets, the abalone is considered the genus of all single shelled mollusks. It has also been called an ormer, sea ear and ear shell in the past. Somewhat resembling a snail, the abalones body is little more than a muscular foot with a head at one end that bears a pair of eyes and sensory tentacles. Tentacles also fringe the body. There is a line of holes over the top of the abalones shell through which water is exhaled after it is drawn in under the shell and over the gills to extract oxygen. As the shell grows forward new holes are formed and the old holes become covered over. Only a few of the younger holes are open at any one time while the rest appear as a line of bumps. In some cases abalones have been discovered that rank them among the largest shellfish. On an average they will range in size from one inch long to the very rare Haliotis pourtalese, which is found off the Florida coast to the red abalone of California, which is a foot across.
Found throughout the world from the coast of the Mediterranean, Africa, Australia, New Zealand, the Pacific islands, to the western coast of North America, abalones can even be found as far north as St. Malo and the Channel Islands. The Haliotis pourtalese is known mainly from the specimens washed up on the shores since they live at depths of 350 feet to 1,200 feet in the ocean. This makes it the deepest living species of abalone known to man. Most abalones live between the extreme low water mark and at a depth of about 60 feet along rocky shores where there is no sand to clog their gills. Some live in rocky pools large enough not to be heated too quickly by the sun. The black abalone lives in the splash zone where waves break against the rocks. This allows the water to alternate between covering and exposing them.
Unlike some of their relatives, abalones have no one home. Instead they simply hide up in a crevice or under a rock to avoid light and then come out at night. If disturbed an abalone will grip the rocks face with its foot as a suction pad. They have two main muscles in their body that exert up to 400 pounds of force in a 4-inch specimen. Abalones cannot bring their shell down over the whole of their bodies as with some of their relatives. There is always the edge of the foot and a frill of tentacles left sticking out. Moving in the same way as limpets and snails, waves of muscular contractions pass along the foot pushing the abalone forward. When each part expands it is fixed to the ground by slimy mucus with the part in front expanding in turn pressing forward and then sticking itself down. Their movement is a sort of bipedal one with one side moving while the other side stays fixed. For a shellfish the abalones travel quickly at a speed of 5 to 6 yards per minute in some cases.
During the free-swimming stage the mortality rate for abalones is heavy. Adults have several enemies including fish, sea birds, otters, crabs and starfish. Their only protection is in their tenacity in clinging to rocks and the protective camouflage of their shell and foot. They are also vulnerable to boring sponge, which erodes holes in their shells to open them up to other predators. Occasionally a dark pearl called the blister pearl can be found in abalones. These are formed by the animal to cover up a source of irritation. As a rule, abalones are vegetarians that feed mostly on red seaweed. Food is scraped up and chewed into small pieces by the rasp like action of a tongue made up of large numbers of small, chalky teeth. All abalones are of one sex or the other and reach sexual maturity in six years. The female will release over 100,000 eggs and the male will shed a 3-foot radius of spawn to fertilize the eggs. These are covered with a gelatin coat and will float freely in the ocean until they hatch. After hatching millions are eaten by plankton eating fish before the three days it takes for them to sink to the bottom to start becoming adults is up. Abalones are prized for their meat and shells. The shells, although superficially rough and dull, reveal the gleam of mother or pearl when they are cleaned.