Metamorphosis of the Leptocephali of the Tenpounder, Elops hawaiensis, from Ishigaki Island, Japan

Abstract

Several leptocephali of the genus Elops, collected from Ishigaki Island, Ryukyu Islands, were reared, and the process of metamorphosis was clarified. Consequently larval development can be divided into four phases, i. e., leptocephalus phase, 1st metamorphic phase, 2nd metamorphic phase and juvenile phase, mainly by the position of the dorsal and anal fins, gas bladder shape, body shape and size, pigmentation, dentition, ossification of the endoskeleton and growth rate.
The larvae have 66-68 myomeres and 67 vertebrae, and are identified as Elops hawaiensis. The present study suggests that the Japanese species of Elops is E.hawaiensis, not E. machnata as previously recorded.