Genetic improvement of percids

During the past years, breeding programs for aquaculture have shown fast development. Globally, economically highly relevant species have experienced implementation of large scale breeding programs and it is impossible to imagine life today without them as they significantly improve production and profitability of enterprises. However, there are still many aquatic species cultured that rely on wild broodstock and for which there is no breeding program. The reasons for not having breeding programs are diverse: The knowledge to execute a breeding program is often not available, and more importantly, breeding programs are considered expensive. Costs for separate family rearing systems, testing environments, extensive tagging etc. are often limiting. Farming of percids is a new sector where pioneering farmers have to develop rearing systems, reproduction methodology, fish feeds, etc., all at the same time. Especially in such cases, low-cost methods are required to get their business up and running. For this reason, many farms consider the foundation of a basic breeding program as their least concern, only to reduce costs. However, we argue that there are good reasons to start with selective breeding at the very start of an aquaculture enterprise. In the next chapters, the principles of selective breeding programs will be described. This includes a basic description of the concept of estimating the heritable components of the phenotypic appearance of fish. Next the most commonly used selection methods and their implication for percids will be discussed. The potential traits for selection that should be relevant in percid culture are reviewed. Some insights into the optimisation of breeding programs and an overview of basic breeding program management will be presented. We present an outline of how to maintain genetic diversity within cultured stocks, with a special focus on limiting rates of inbreeding while selecting. Finally, some insights on how to manage costs and benefits of breeding programs are discussed.