The genetic management of fish domestication

Abstract

Since 1950, the number of fish species used in aquaculturehas increased from 42 to 186. Due to this greatdiversity, to the fact that most species have been bredfor a short time, and to the existence of wild geneticresources, domestication is a recurring question inaquaculture development. Genetic aspects of domesticationrelate to two main aspects : the initial setup ofbreeding techniques and creation of stocks, and themanagement of populations across generations, to provideboth production efficiency and animal welfare.Concerning the first aspect, the scarce existing studiesshow that it might be difficult to draw conclusionsregarding the ability of a particular population toadapt to a captive environment, based only on geneticvariability at neutral markers or on ecological observationsin the wild. A strain evaluation program may beconducted prior to the start of the breeding program. Itmust however be done under controlled conditions, asclose as possible to the future breeding conditions. Inany case, it is advisable to start the domestication processfrom a population with a large genetic basis, andto manage it in order to maintain suitable levels ofgenetic variability across generations. The domesticationprocess leads to important changes in many physical,ethological and/or physiological traits, but thegenetic mechanisms of these changes are not alwayscontrolled. It could be however possible to direct theevolution of adaptive traits, through targeted selectivebreeding programs.