How do larval fish use their muscles to swim?
Fish start swimming directly after hatching, and immediately they need to optimally coordinate their muscles to evade predators. Although a considerable amount of research was carried out on larval swimming, we know very little about how axial muscles power different swimming modes, and how muscle activations differ between adults and larvae. During development, larval fish not only grow rapidly in size, but also undergo fast changes in muscle morphology and physiology. Muscle fibres, for example, change their orientation from nearly rostro-caudal to a complex helix during development. How this rearrangement develops in time across the body and how this relates to swimming kinematics, is currently unclear. To understand how the spatio-temporal muscle fibre activity pattern powers swimming in larval fish we will investigate both the morphological changes and the activity patterns in the axial muscles during development.