ABSTRACT
The importance of finfish aquaculture continues to increase due to overfishing of natural fish stocks in oceans, as reported in recent decades. Understanding and controlling the process of fish reproduction is one of the crucial factors enabling aquaculture development. Successful incorporation of methods establishing fast-growing and sterile fish hybrids, monosex strains or polyploid organisms, strongly depends on the availability of tests for checking out the efficiency of such techniques. The chapter highlights the application of cytogenetic techniques in modern aquaculture. Rapid development of fish cytogenetics has focused on constructing standard karyotypes of fish species, chromosomal localization of particular DNA sequences and revealing chromosome anomalies. Genetic studies of hybrids encompass, among others, methods, which directly or indirectly identify parental chromosomes and enable estimation of the efficiency of hybridization process. Crossing individuals derived from the same species but from different lines, populations or strains has to be followed by more precise studies concerning parental genome identification.
