Morphological Development and Growth of Laboratory-reared Spotted Halibut Verasper variegatus

Morphological development and somatic growth were examined for laboratory-reared spotted halibut, Verasper variegatus, from newly-hatched larvae to early stage of juveniles. Nine developmental stages (A-I) were recognized based on morphological characteristics. Newly hatched larvae were measured 3.8-4.2mm in total length (TL), with unpigmented eyes, unopened mouth and anus (stage A). On 25 days after hatching (DAH), notochord flexion began at 9.4-10.5mm TL (stage E), and was completed at 10.7-14.1mm TL on 30 DHA (stage F). The migration of the left eye over the dorsal median line from a symmetrical position occurred at 13.8mm TL on 35 DAH (stage G), and was completely translocated to one side at 16.1mm TL on 50 DAH (stage I). Pigmentation of melanophores on the body and fins became prominent as larval development proceeded, being densely distributed on whole body at stage H. A few posterior and anterior preopercular spins appeared at 8.4mm TL and disappeared at 18.0mm TL. The flexion points in the relative growth of body parts were located at the stages of mouth opening, initiation of notochord flexion at early and mid phases of metamorphosis. When compared with related species barfine flounder V. moseri, distribution of melanopores exclusive of stages D and H, and TLs at stages D to G, and proportions of some body parts were different, though general developmental pattern and morphological characteristics were similar.