Shad, the name applied to several species of fish of the herring family. Shad are bony fish with deeply forked tails. They spend most of their lives in the ocean and feed mostly on plankton. In spring or early summer, shad leave the ocean and enter freshwater coastal rivers to spawn. The female sheds an average of about 30,000 pale pink or amber eggs. The eggs hatch in about 6 to 10 days. After spawning, the parent shad leave the river and go back to the ocean; the young stay until autumn, then migrate out to the ocean. Only mature shad that are four years of age or over are able to spawn.Shad enter freshwater coastal rivers to spawn.
Some shad are important food fish in North America and Europe. They are caught in nets as they enter coastal rivers to spawn. Most of the catch is sold fresh. The eggs of the shad, called roe, are considered a delicacy in North America.
The American shad is the largest and best-known shad of North America. It is native to the Atlantic coast from the Gulf of St. Lawrence to the St. Johns River in Florida. In 1871, it was introduced to the Pacific coast and is now found there from southern California to Alaska. The American shad is deep blue to blue-green on its back with silver sides. Behind the gills are a large dark spot and several smaller and lighter spots. The average American shad is about 24 inches (60 cm) long and weighs about 4 pounds (1.8 kg).
The American shad is Alosa sapidissima. Shad are of the herring family, Clupeidae.