Myosin, the major component of striated muscle, is a complex molecule of heavy and light chains, which undergo continuous replacement to meet developmental and environmental demands. A range of myosin isoforms are expressed in early developmental stages and are of special interest as they offer information about muscle formation and function early in life. In addition, they can act as markers for the study of prenatal events with an effect on postnatal growth performance. In this study, the spatial and temporal expression of embryonic myosin light chains 1 (MLC1) and 2 (MLC2) was studied in sea bream larvae post-hatch by in situ hybridization using riboprobes