Venerupis philippinarum

Venerupis philippinarum (syn. Ruditapes phlippinarum) is an edible species of saltwater clam in the family Veneridae, the Venus clams. Common names for the species include Manila clam, Japanese littleneck clam, Japanese cockle and Japanese carpet shell. This clam is commercially harvested, being the second most important bivalve grown in aquaculture worldwide. The shell of Venerupis philippinarum is elongate, oval, and sculptured with radiating ribs. It is generally 40 to 57 millimeters wide, with a maximum width of 79 millimeters. The shell is quite variable in color and patterning, being cream-colored to gray with concentric lines or patches. Individuals living in anoxic conditions may be black. The inside surface of the shell is often white with purple edges. The siphons are separated at the tips. This clam is native to the coasts of the Indian, Philippines and Pacific Oceans from Pakistan and India north to China, Japan, and the Kuril Islands. It has a very wide nonnative distribution, having been introduced accidentally and purposely as a commercially harvested edible clam. It is now permanently established in coastal ecosystems in many parts of the world. It is common along the Pacific coast of North America from British Columbia to California, where its original introduction was accidental. It can be found in Hawaii. It was first seeded in the waters of Europe in the 1970s, and there have been multiple introductions throughout the region. It has spread naturally in Western Europe over the decades, its adaptability allowing it to thrive in many coastal habitat types. It has been planted in Portugal, Spain, the United Kingdom, Italy, Germany, Morocco, Israel, and French Polynesia for the purposes of aquaculture. This burrowing clam is most abundant in subtropical and cooler temperate areas. It can be found in shallow waters in substrates of coarse sand, mud, and gravel. It lives in the littoral and sublittoral zones. It burrows no more than about 10 centimeters into the substrate. It sometimes lives in eelgrass beds. This species lives in many types of habitat, being found in the intertidal zone, brackish waters, estuaries, and under ice. It survives in a range of salinities and temperatures, with narrower ranges required for breeding. This clam may become sexually mature in its first year of life, when it reaches about 15 millimeters in width, especially in warmer areas such as Hawaii. In cooler areas it begins breeding at older ages and larger sizes. In warmer regions it spawns year-round, but only in the summer in cooler areas. The fecundity of the species increases with size, a 40-millimeter female producing up to 2.4 million eggs.