Stages of Embryonic Development of the Ice Goby (Shiro-uo), Leucopsarion petersii

A series of normal stages for the embryonic development of the ice goby (shiro-uo), Leucopsarion petersii, which belongs to the Perciformes, is described. Stages are based on morphological features, by utilizing the optical transparency of live embryos from the first cleavage to the hatching stage. Fertilized eggs were obtained by artificial insemination and normal embryogenesis was accomplished in a defined medium in plastic petri dishes at 19°C. Shiro-uo eggs were surrounded by a very thin and clear chorion and could be dechorionated with forceps very easily. Developmental stages were mostly comparable to those of other fish embryos described so far, but several differences were indicated, such as the third cleavage plane being horizontal, and that the length of the cleavage cycle increased gradually from the very early stages. Also, there were differences in the relative rates of organogenesis of the brain, eyes, otic vesicles, and somites when compared to the zebrafish and medaka.