Dog′fish, the common name for a group of small salt-water sharks and also for a fresh-water fish. The smooth dogfish without a spine and the spiny dogfish with a spine on each of the two dorsal fins are very abundant along the Atlantic coast. They are slate-color above and whitish below, and attain a length of about three feet. They are migratory, going into the southern waters in winter and returning north in the spring. Late in May and early in June they appear on the southern coast of Massachusetts, and work northward around Cape Cod and up to the coast of Maine. They are caught on hooks for the oil contained in their livers. When abundant, they are troublesome to the fishermen, eating their bait and driving away other fish. They carry from two to twelve eggs in oviducts, and the young are hatched within the body of the parent. The fresh-water dogfish (amia), often called the bowfin, belongs to the ganoids, a group of fishes with very hard, enamel-like scales.
