Larval morphology of striped bonito, Sarda orientalis, with comments on distinction from kawakawa, Euthynnus affinis

The morphologies of a developmental series of larval and juvenile specimens of striped bonito, Sarda orientalis are described and compared with kawakawa, Euthynnus affinis . Larval specimens of S. orientalis are characterized by presence of a supraoccipital protrusion, spines on the supraorbital ridges, forebrain pigments, isthmus pigments, pelvic fin pigments, a large pigment patch on caudal fin base, and well-developed jaws and teeth. Striped bonito and kawakawa larvae closely resemble each other morphologically but can be distinguished by combinations of various external characteristics.