Development of the sense organs of ribbonfish Trichiurus lepturus larvae and juveniles.

Abstract

The morphology of the sense organs of the larvae and juveniles of the ribbonfish Trichiurus lepturus in Wakasa Bay was examined to obtain insights on changes in behavior and habitats with growth of the fish. Development of the sense organs proceeded in accord with the rest of the morphological development of the larvae and juveniles. Sense organs required for feeding were formed at the onset of exogenous feeding. The taste buds first appeared at the begining of the postlarval period and increased in number in association with the pharyngeal teeth and gill arches. During the late phase postlarval period, the lateral line canal on the head and the olfactory rescue were formed. The retinae became duplex and developed horizontal cells in three layers; this is inferred to be advantageous for a piscivorous feeding habit. The presence of well developed sense organs synchronized with the active migration of postlarvae from offshre to coastal waters.