The Herrings (Clupeidae): The Clupeidae Family consists of Herrings, Menhadens, Pilchards, Piquitingas, Sardines, Shads, and Threadfin Herrings. In general, they are small silvery shallow water fishes that are found in all cold and warm waters of the seas. They normally travel in schools that consist of hundreds to thousands of individuals.

They feed primarily on zooplankton. They are characterized by their scuted keels along the entire belly, a single dorsal fin in the middle of the body, anal fins that are well back with a short base, pelvic fins on the abdomen below the dorsal fin, pectoral fins that are low on the sides and their fins have no spines.

Herrings are of major importance to fisheries comprising 50 percent of the global catch of fishes each year. Globally, 227 species of Clupeidae have been identified, of which only 11 are found in the tropical Eastern Pacific. Members of the Herring Family represented in the photo identification section of this website include: the Deepbody Thread Herring, Opisthonema liberatate; the Pacific Thread Herring, Opisthonema libertate; the Sardina or Flatiron Herring, Harengula thrissina; the Middling Thread Herring, Opisthonema medirastre; the Striped Herring, Lile stolifera; and the Yellowfin Herring, Pliosteostoma lutipinnis.