Skeletal deformities in larval, juvenile and adult stages of cultured gilthead sea bream (Sparus aurata L)

Gilthead sea bream (Sparus aurata L.) is currently farmed in a number of European countries. In culture exploitations, spinal malformations are frequently seen in adult specimens. We studied skeletal deformities in larval, juvenile and adult stages of fish from a Spanish experimental culturing centre. About 27% of sea bream larvae at hatching showed different types of axial deformations that were related to notochord alterations during embryogenesis. About 22% died soon after hatching, but 5% survived and reached juvenile and adult stages. These fish were mostly lordotic. Juvenile lordotic fish displayed uninflated swimbladders but all lordotic adults possessed an inflated functional swimbladder. Lordosis is characterised by V-shaped dorsoventral curvature of the body axis including the vertebral column and the spinal cord. Spinal curvature occurred more frequently between vertebrae 10 and 16. The congenital or postnatal origin of lordosis is discussed.