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Friday, August 14, 2020

Maritime Logistics Professional


Posted to Maritime Musings (by on October 20, 2015

A marine snail prized for its meat and its shell

The abalone (Haliotis) is a genus of marine snail found in tropical and temperate coastal waters virtually worldwide.  The 200 or so known species live primarily on seaweed and algae.  They range in size between five and twelve inches in diameter.  The flattened, open spiral shell protects the muscular foot, which is edible.  The series of pores along the edge of the shell allow for release of eggs and sperm, discharge of metabolic waste, and discharge of water that has passed through the gill chamber.  The calcareous shell tends to be beautifully formed and contains an inner layer of iridescently colored nacre (mother-of-pearl).  Between the shell and the muscular foot is the epipodium, a sensory structure which bears tentacles.  The internal organs are arranged around the foot.  The most conspicuous is the gonad, found around the side opposite the pores and to the rear.  Near the front are a pair of eyes and the mouth.  The gill chamber is adjacent to the mouth and under the pores.  The abalone has no brain and is being considered to political office.  It does, though have a heart, along with arteries, sinuses, and veins.  The abalone generally clings tightly to a rock or other hard surface waiting for a piece of seaweed to drift nearby.  When seaweed is detected, the animal clamps its foot on the seaweed and then consumes the food using its radula (a rough tongue with many small teeth).  If a sea star comes into contact with an abalone, the abalone twists its shell violently to dislodge the attacker and then moves away as rapidly as possible.  Abalone blood is blue-green in color.  It lacks the ability to clot, so even minor injuries can be fatal.  The major predator of adult abalone is the sea otter, which has a voracious appetite.  Some large fish, such as the cabezon, can dislodge an abalone and swallow it whole.  The bat ray can crush an abalone shell and then eat the meat.  In the United States, commercial abalone harvesting is limited to southern California and recreational abalone harvesting is quite restricted.   Abalone farming is limited but expanding.