Sea food consumption is an important component of healthy diet. Increase in aquaculture production is required to compensate rarefaction of sea food from wild fisheries. A challenge facing aquaculture industry is to increase fish flesh production while maintaining nutritional value and quality of the product. Hyperplasia, a process by which small new fibres are added into the fish myotome is an important determinant of muscle growth rate (flesh production) in fish. Also a high number of small fibres resulting from hyperplasia is correlated with a high collagen content that positively influence texture. However, so far, almost nothing is known regarding the genetic circuits controlling the continuous muscle fibre production, a trait linked to productivity and profitability of fish enterprise. Therefore, the aim of this project is to provide the genetic basis for hyperplastic growth in fish. This includes (i) an idenfication of genes specifically expressed in hyperplastic area of the myotome using transcriptomic tools and in situ hybridization screen and a functional analysis of hyperplasia candidate genes by means of antisens morpholinonucleotides and transgenic approaches.