Scapharca subcrenata (Lischke)

Classification status and distribution: Mollusca, Salamandae, Scapharidae, Scapharca, genus Scapharca, mainly distributed in China, Korea and Japan coastal. There are more offshore areas in China's Bohai Sea and East China Sea. They live in the mud and sand bottom of the shallow sea in the inner bay from the low tide line to a water depth of more than ten meters, with the majority being 4-8 meters tall.

Morphological characteristics: The adult shell is 4-5 cm long, the shell surface is swollen and oval, the top of the shell is protruding and rolled inward and biased to the front; the shell surface has 30-44 radiating ribs, and the ribs are visible Small square tubercle; hinge straight, with about 50 teeth; shell surface white, covered with brown hairs. Biological characteristics: The digestive organs are composed of the mouth, esophagus, stomach, intestines, and anus. The main food is diatoms and organic debris. The gonads are wrapped around the digestive glands (visceral mass). When sexually mature, the female gonads are (purple) red and the males are yellow-white. The genital pores open on the ventral surface of the posterior adductor muscle, one on each side. The eggs (egg diameter 50-60 microns) are fertilized and hatched in seawater. Hairy clams living in Liaodong Bay of the Bohai Sea mostly lay eggs from early July to early August; during the breeding period, there are 2-3 peak sperm and egg discharges, with an interval of about half a month between each time. An individual with a shell length of 4 cm can ovulate up to 2 million to 3 million eggs at a time. The water temperature for spawning is mostly between 25-27℃. The larvae float in the sea water and enter the D-shaped larvae in the wheel larvae stage. At 150 microns, the top of the shell begins to be significantly larger than the shell height and is nearly ovoid. After the shell reaches 220 microns, "eyespots" appear and they are about to enter the attached metamorphosis life. . The entire floating period takes about 16-17 days. After the larvae end their planktonic life, they attach themselves to solid objects such as sand, shells, and seaweed with their byssus. The byssus is ribbon-shaped and exists throughout life; it has the ability to regenerate and attach after falling off. When the shell is 1.2-1.5 cm long, it falls to the bottom of the sea and enters shallow burial life. It takes about 2-2.5 years to grow into a shell.

Economic significance: Edible shellfish with high vitamin B12 content.