Early ontogeny of chromatophores and skin color changes of spotted halibut (Verasper variegatus)

The abnormity of flatfish is very common in seeding breeding in aquaculture, and the morphological characteristics and distribution of chromatophores, as well as skin color changes during early life history(0–72 d)of Verasper variegatus were continuously observed and photographed, in order to offer reference for research and practice later. Results showed that the whole period of early development of spotted halibut lasted about 50 days in spawning water at 12–19.5 °C, and there was a rapid growing period after 20 days old.The larval melanophores occurred first and had the most contents, then xanthophores occurred, and iridophoress occurred finally. The larval cytochrome of fry body were distributed symmetrically before metamorphosis, with an increase of the melanophores density firstly and a decrease of the density followed, and the maximal density of melanophores were 1390 cells/mm²at 9 days old. When metamorphosis occurred, the cytochrome and skin color of fry became asymmetrical. On ocular side, larval melanophores of fry body disappeared and were replaced by adult ones, and skin color was saturated and black, and the density of melanophores was stable, about 150 cells/mm² . However, on blind side, larval melanophores disappeared and no adult ones appeared, and skin color was white. In our study, albinism often occurred at metamorphosis (35 days old), and adult melanophores of ocular side were blocked, and could not pass the metamorphosis period, and became albino.