Early ontogeny of the big roughy Gephyroberyx japonicus (Beryciformes: Trachichthyidae) in captivity

摘要

Development of eggs and larvae of the big roughy Gephyroberyx japonicus are described on the basis of specimens reared in captivity. Spherical eggs (diameter 1.26-1.35 mm) with a single oil globule were pelagic. Newly hatched larvae (2.8-3.1 mm in body length, BL) had strong linear pigmentation on the head and trunk. The mouth opened at ca. 3.5 mm BL; thereafter the yolk was absorbed. Notochord flexion started at ca. 4.5 mm BL when body depth increased rapidly, and melanophores spread to all of the body. Notochord flexion was completed at ca. 5.0 mm BL. Head spination and pelvic fins began to develop during the flexion stage.