On the Identification, Distribution, and Biology of the Dolphins, Coryphaena Hippurus and C. Equiselis

Coryphaena hippurus, the common dolphin, and C. equiselis, the pompano dolphin, have been studied. The specific name equiselis is considered valid, as opposed to the emended form, equisetis. The two species differ markedly in numbers of dorsal and anal rays and lateral-line scales, in morphometric characters which reflect depth, in relative heights of dorsal and anal fins, in the shape of the tooth patch on the tongue, and in the color pattern and head spination of the young. Weights of males and females are similar below about 950 mm, after which males appear heavier. Both species are probably cosmopolitan in warm seas. C. hippurus is most often caught in waters over 70°F. Adults of C. equiselis are seldom caught and are probably more pelagic and more tropical. C. hippurus breeds in summer in the Gulf Stream, earlier in the Caribbean. Young C. hippurus are, paradoxically, less abundant than those of C. equiselis, particularly in the Gulf of Mexico and Florida Current. The sex ratio of C. hippurus is 50:50 in the Gulf Stream, but females apparently predominate in Caribbean sport catches. Stomach analyses show fishes to be the most abundant item in the diet of C. hippurus, with no evidence of selectivity. There is some indication that feeding is inhibited at night.