menhaden, any of several species of valuable Atlantic coastal fishes in the genus Brevoortia of the herring family (Clupeidae), utilized for oil, fish meal, and fertilizer. Menhaden have a deep body, sharp-edged belly, large head, and tooth-edged scales. Adults are about 37.5 cm (about 15 inches) in length and 0.5 kg (1 pound) or less in weight. Dense schools of menhaden range from Canada to South America. When feeding, they swim with mouths agape and gill openings widespread to strain out plankton. Menhaden spawn at one place or another throughout the year. Their buoyant eggs hatch in about two days. The young grow rapidly and mature at about three years. Large numbers of menhaden are netted annually. The fish meal, mainly used as animal feed, may someday provide inexpensive and easily obtained protein for humans.